Cilinical anatomy upper limb

Cilinical Upper Limb
KLM & Snell
Dr M Idris Siddiqui

Witch’s Milk in the Newborn
While the fetus is in the uterus, the maternal and
placental hormones cross the placental barrier and
cause proliferation of the duct epithelium and the
surrounding connective tissue.
This proliferation may cause swelling of the
mammary glands in both sexes during the first week
of life; in some cases a milky fluid, called witch’s milk,
may be expressed from the mipples.
The condition is resolved spontaneously as the
maternal hormone levels in the child fall.

Breast Examination
The breast is one of the common sites of cancer in women. It is also the site of
different types of benign tumors and may be subject to acute inflammation
and abscess formation.
With the patient undressed to the waist and sitting upright,
I. The breasts are first inspected for symmetry. Some degree of asymmetry
is common and is the result of unequal breast development.
II. Any swelling should be noted. A swelling can be caused by:
a. an underlying tumor,
b. a cyst, or
c. abscess formation.
III. The nipples should be carefully examined for evidence of retraction. A
carcinoma within the breast substance can cause retraction of the nipple
by pulling on the lactiferous ducts. The patient is then asked to lie down so
that the breasts can be palpated against the underlying thoracic wall.
IV. Finally, the patient is asked to sit up again and raise both arms above her
head. With this maneuver, a carcinoma tethered to the skin, the
suspensory ligaments, or the lactiferous ducts produces dimpling of the
skin or retraction of the nipple.

Supernumerary and Retracted Nipples
Supernumerary nipples occasionally occur along a line
extending from the axilla to the groin; they may or may
not be Associated with breast tissue.
This minor congenital anomaly may result in a mistaken
diagnosis of warts or moles.
A long-standing retracted nipple is a congenital deformity
caused by a failure in the complete development of the
nipple.
A retracted nipple of recent occurrence is usually caused
by an underlying carcinoma pulling on the lactiferous
ducts.

The Importance of Fibrous Septa
The interior of the breast is divided into 15 to 20 compartments
that radiate from the nipple by fibrous septa that extend from
The deep surface of the skin. Each compartment contains a lobe
of the gland.
Normally, the skin feels completely mobile over the breast
substance.
However, the fibrous septa become involved in a scirrhous
carcinoma or in a disease such as a breast abscess, which results
in the production of contracting fibrous tissue, the septa will be
pulled on, causing dimpling of the skin. The fibrous septa are
sometimes referred to as the Suspensory ligaments of the
mammary gland.

Breast Abscess
An acute infection of the mammary gland may occur
during lactation. Pathogenic bacteria gain entrance to
the breast tissue through a crack in the nipple.
Because of the presence of the fibrous septa, the
infection remains localized to one compartment
or lobe to begin with.
• Abscesses should be drained through a radial
incision to avoid spreading of the infection into
neighboring compartments; a radial incision also
minimizes the damage to the radially arranged
ducts

Carcinoma in the Male Breast
Carcinoma in the male breast
accounts for about 1% of all
Carcinomas of the breast.
This fact tends to be overlooked
When examining the male patient.

Breast Quadrants
For the anatomical location and
description of pathology (e.g., cysts
and tumors), the breast is divided into
four quadrants.
The axillary tail is an extension of the
mammary gland of the superolateral
quadrant.

Changes in Breasts
Changes, such as branching of the lactiferous ducts, occur
in the breast tissues during the menstrual cycle and
pregnancy. Although mammary glands are prepared for
secretion by midpregnancy, they do not produce milk
until shortly after the baby is born.
Colostrum, a creamy white to yellowish premilk fluid, may
secrete from the nipples during the last trimester of
pregnancy and during initial episodes of nursing.
Colostrum is believed to be especially rich in protein,
immune agents, and a growth factor affecting the
infant's intestines. In multiparous women (those who
have given birth two or more times), the breasts often
become large and pendulous. The breasts in elderly
women are usually small because of the decrease in fat
and the atrophy of glandular tissue.

Carcinoma of Breast
Carcinomas of the breast are malignant tumors, usually adenocarcinomas arising from the
epithelial cells of the lactiferous ducts in the mammary gland lobules. Metastatic cancer cells
that enter a lymphatic vessel usually pass through two or three groups of lymph nodes before
entering the venous system.
Breast cancer can spread via lymphatics and veins and as well as by direct invasion.
Interference with the lymphatic drainage by cancer may cause lymphedema (edema, excess
fluid in the subcutaneous tissue), which in turn may result in deviation of the nipple and a
thickened, leatherlike appearance of the skin . Prominent or “puffy” skin between dimpled
pores gives it an orange-peel appearance (peau d'orange sign). Larger dimples (fingertip size or
bigger) result from cancerous invasion of the glandular tissue and fibrosis (fibrous
degeneration), which causes shortening or places traction on the suspensory ligaments.
Subareolar breast cancer may cause inversion of the nipple by a similar mechanism involving the
lactiferous ducts.
Abundant communications among lymphatic pathways and
among axillary, cervical, and parasternal nodes may also
cause metastases from the breast to develop in the
supraclavicular lymph nodes, the opposite breast, or the
abdomen.

Carcinoma of Breast
• Because most of the lymphatic drainage of the breast is to the axillary
lymph nodes, they are the most common site of metastasis from a breast
cancer. Enlargement of these palpable nodes suggests the possibility of
breast cancer and may be key to early detection.
• However, the absence of enlarged axillary lymph nodes is no guarantee that
metastasis from a breast cancer has not occurred because the malignant
cells may have passed to other nodes, such as the infraclavicular and
supraclavicular lymph nodes.
• Nodal metastatic breast cancer can be difficult to manage because of the
complex system of lymphatic drainage. The posterior intercostal veins drain
into the azygos/hemiazygos system of veins alongside the bodies of the
vertebrae and communicate with the internal vertebral venous plexus
surrounding the spinal cord.
• Cancer cells can also spread from the breast by these venous routes to the
vertebrae and from there to the cranium and brain. Cancer also spreads by
contiguity (invasion of adjacent tissue). When breast cancer cells invade the
retromammary space, attach to or invade the pectoral fascia overlying the
pectoralis major, or metastasize to the interpectoral nodes, the breast
elevates when the muscle contracts. This movement is a clinical sign of
advanced cancer of the breast.

Mammography
Mammography is a radiographic examination of
the breast used to detect breast masses.
• This technique is extensively used for screening the
breasts for benign and malignant tumors and cysts.
• Extremely low doses of x-rays are used so that the
dangers are minimal, and the examination can be
repeated often.
• Its success is based on the fact that a lesion
measuring only a few millimeters in diameter can
be detected long before it is felt by clinical
examination.

Surgical Incisions of Breast
Incisions are placed in the inferior breast quadrants when
possible because these quadrants are less vascular than
the superior ones. The transition between the thoracic
wall and breast is most abrupt inferiorly, producing a line,
crease, or deep skin fold—the inferior cutaneous crease.
Incisions made along this crease will be least evident and
may actually be hidden by overlap of the breast.
• Incisions that must be made near the areola or on the
breast itself are usually directed radially to either side of
the nipple (Langer tension lines run transversely here or
circumferentially).

Mastectomy
Mastectomy (breast excision) is not as common as it once
was as a treatment for breast cancer.
In simple mastectomy, the breast is removed down to the
retromammary space.
Radical mastectomy, a more extensive surgical procedure,
involves removal of the breast, pectoral muscles, fat, fascia,
and as many lymph nodes as possible in the axilla and
pectoral region.
In current practice, often only the tumor and surrounding
tissues are removed—a lumpectomy or quadrantectomy
(known as breast-conserving surgery, a wide local excision)—
followed by radiation therapy

Development of the Breasts
In the young embryo, a linear thickening of ectoderm appears
called the milk ridge, which extends from the axilla obliquely to
the inguinal region.
In animals, several mammary glands are formed along this
ridge.
In the human, the ridge disappears except or a small part in the
pectoral region. This localized area thickens, becomes slightly
depressed, and sends off 15 to 20 solid cords, which grow
into the underlying mesenchyme. Meanwhile, the underlying
mesenchyme proliferates, and the depressed ectodermal
thickening becomes raised to form the nipple. At the fifth
month, the areola is recognized as a circular pigmented area
of skin around the future nipple.

Anomalies of breast
Polythelia:
Supernumerary nipples occasionally occur along a line corresponding to the position
of the milk ridge. They are liable to be mistaken for moles.
Retracted Nipple or Inverted Nipple:
Retracted nipple is a failure in the development of the nipple during its later stages. It
is portant clinically, because normal suckling of an infant cannot take place, and the
nipple is prone to infection.
Micromastia:
An excessively small breast on one side occasionally occurs, resulting from lack of
development.
Macromastia:
Diffuse hypertrophy of one or both breasts occasionally occurs at puberty in otherwise
normal girls.
Gynecomastia:
Unilateral or bilateral enlargement of the male breast occasionally occurs, usually at
puberty. The cause is unknown, but the condition is probably related to some form of
hormonal imbalance.

Dislocation of the Acromioclavicular Joint
• Although its extrinsic coracoclavicular ligament is strong, the
AC joint itself is weak and easily injured by a direct blow.
• In contact sports such as football, soccer, hockey, or the
martial arts, it is not uncommon for dislocation of the AC joint
to result from a hard fall on the shoulder or on the
outstretched upper limb.
• Dislocation of the AC joint can also occur when a hockey
player is driven into the boards or when a person receives a
severe blow to the superolateral part of the back. An AC joint
dislocation, often called a shoulder separation, is severe when
both the AC and the coracoclavicular ligaments are torn.
When the coracoclavicular ligament tears, the shoulder
separates from the clavicle and falls because of the weight of
the upper limb. Dislocation of the AC joint makes the
acromion more prominent, and the clavicle may move
superior to this process.

Variations of the Clavicle
• The clavicle varies more in shape than most other
long bones.
• Occasionally, the clavicle is pierced by a branch of
the supraclavicular nerve.
• The clavicle is thicker and more curved in manual
workers, and the sites of muscular attachments are
more marked.
• The right clavicle is usually stronger and shorter
than the left clavicle.

Fractures of the Clavicle
**It is the most commonly fractured bone in the body.
• After the fracture, the lateral fragment is Depressed by the weight of the
arm, and it is pulled medially and forward by the strong adductor muscles of
the shoulder joint, especially the pectoralis major. The medial end is tilted
upward by the sternocleidomastoid muscle.
• The close relationship of the supraclavicular nerves to the clavicle may
result in their involvement in callus formation after fracture of the bone. This
may be the cause of persistent pain over the side of the neck.
• The slender clavicles of newborn infants may be fractured during
delivery if the neonates are broad shouldered; however, the bones
usually heal quickly. A fracture of the clavicle is often incomplete in
younger children that is, it is a greenstick fracture, in which one side of
a bone is broken and the other is bent.
– This fracture was so named because the parts of the bone do not separate; the
bone resembles a tree branch (greenstick) that has been sharply bent but not
disconnected

Fracture of the Clavicle
• Clavicular fractures are especially common in children and are often caused
by an indirect force transmitted from an outstretched hand through the
bones of the forearm and arm to the shoulder during a fall.
• A fracture may also result from a fall directly on the shoulder.
• The weakest part of the clavicle is the junction of its middle and lateral
thirds.
• After fracture of the clavicle, the sternocleidomastoid muscle elevates the
medial fragment of bone. Because of the subcutaneous position of the
clavicles, the end of the superiorly directed fragment is prominent readily
palpable and/or apparent. The trapezius muscle is unable to hold the lateral
fragment up owing to the weight of the upper limb, and thus the shoulder
drops.
• The strong coracoclavicular ligament usually prevents dislocation of the AC
joint.
• People with fractured clavicles support the sagging limb with the other
limb. In addition to being depressed, the lateral fragment of the clavicle
may be pulled medially by the adductor muscles of the arm, such as the
pectoralis major.
• Overriding of the bone fragments shortens the clavicle.

Fall on to an outstretched hand
(FOOSH)

Falls on the Outstretched Hand
In falls on the outstretched hand, forces are transmitted from the
scaphoid to the distal end of the radius, from the radius across the
interosseous membrane to the ulna, and from the ulna to the humerus;
thence, through the glenoid fossa of the scapula to the coracoclavicular
ligament and the clavicle; and finally, to the sternum.
• If the forces are excessive, different parts of the upper limb give way
under the strain. The area affected seems to be related to age.
• In a young child, for example, there may be a posterior displacement
of the distal radial epiphysis; in the teenager the clavicle might fracture;
in the young adult the scaphoid is commonly fractured; and in the
elderly the distal end of the radius is fractured about 1 in. (2.5 cm)
proximal to the wrist joint (Colles’ fracture).

Ossification of the Clavicle
• The clavicle is the first long bone to ossify (via intramembranous
ossification), beginning during the 5th and 6th embryonic weeks from
medial and lateral primary centers that are close together in the shaft of the
clavicle.
• aThe ends of the clavicle later pass through a cartilaginous phase
(endochondral ossification); the cartilages form growth zones similar to
those of other long bones. A secondary ossification center appears at the
sternal end and forms a scale-like epiphysis that begins to fuse with the
shaft (diaphysis) between 18 and 25 years of age and is completely fused to
it between 25 and 31 years of age.
• This is the last of the epiphyses of long bones to fuse. An even smaller
scale-like epiphysis may be present at the acromial end of the clavicle; it
must not be mistaken for a fracture.
• Sometimes fusion of the two ossification centers of the clavicle fails to
occur; as a result, a bony defect forms between the lateral and the medial
thirds of the clavicle. Awareness of this possible congenital defect should
prevent diagnosis of a fracture in an otherwise normal clavicle. When doubt
exists, both clavicles are radiographed because this defect is usually
bilateral

Compression of the Brachial Plexus, Subclavian
Artery, and Subclavian Vein by the Clavicle
The interval between the clavicle and
the first rib in some patients may
become narrowed and thus is
responsible for compression of nerves
and blood vessels.

Variations of the Brachial Plexus
• Variations in the formation of the brachial plexus
are common. In addition to the five anterior rami
(C5-C8 and T1) that form the roots of the brachial
plexus, small contributions may be made by the
anterior rami of C4 or T2. When the superiormost
root (anterior ramus) of the plexus is C4 and the
inferiormost root is C8, it is a prefixed brachial
plexus. Alternately, when the superior root is C6
and the inferior root is T2, it is a postfixed brachial
plexus.

• Variations may also occur in the formation of
trunks, divisions, and cords; in the origin
and/or combination of branches; and in the
relationship to the axillary artery and scalene
muscles.
• For example, the lateral or medial cords may
receive fibers from anterior rami inferior or
superior to the usual levels, respectively.

• In some individuals, trunk divisions or cord formations may
be absent in one or other parts of the plexus; however, the
makeup of the terminal branches is unchanged.
• Because each peripheral nerve is a collection of nerve fibers
bound together by connective tissue, it is understandable that
the median nerve, for instance, may have two medial roots
instead of one (i.e., the nerve fibers are simply grouped
differently). This results from the fibers of the medial cord of
the brachial plexus dividing into three branches, two forming
the median nerve and the third forming the ulnar nerve.
• Sometimes it may be more confusing when the two medial
roots are completely separate; however, understand that
although the median nerve may have two medial roots, the
components of the nerve are the same (i.e., the impulses
arise from the same place and reach the same destination
whether they go through one or two roots).

Brachial Plexus Injuries
• Injuries to the brachial plexus affect movements and
cutaneous sensations in the upper limb. Disease,
stretching, and wounds in the lateral cervical region
(posterior triangle) of the neck or in the axilla may
produce brachial plexus injuries. Signs and symptoms
depend on the part of the plexus involved. Injuries to
the brachial plexus result in paralysis and anesthesia.
• In complete paralysis, no movement is detectable. In
incomplete paralysis, not all muscles are paralyzed;
therefore, the person can move, but the movements
are weak compared with those on the normal side.
• Determining the ability of the person to feel pain (e.g.,
from a pinprick of the skin) tests the degree of
anesthesia.

• Injuries to superior parts of the brachial plexus (C5 and C6)
usually result from an excessive increase in the angle
between the neck and the shoulder. These injuries can occur
in a person who is thrown from a motorcycle or a horse and
lands on the shoulder in a way that widely separates the neck
and shoulder . When thrown, the person's shoulder often hits
something (e.g., a tree or the ground) and stops, but the head
and trunk continue to move. This stretches or ruptures
superior parts of the brachial plexus or avulses (tears) the
roots of the plexus from the spinal cord.
• Injury to the superior trunk of the plexus is apparent by the
characteristic position of the limb (waiter's tip position•), in
which the limb hangs by the side in medial rotation . Upper
brachial plexus injuries can also occur in a newborn when
excessive stretching of the neck occurs during delivery .

• As a result of injuries to the superior parts of the brachial
plexus (Erb-Duchenne palsy), paralysis of the muscles of the
shoulder and arm supplied by the C5 and C6 spinal nerves
occurs: deltoid, biceps, brachialis, and brachioradialis.
• The usual clinical appearance is an upper limb with an
adducted shoulder, medially rotated arm, and extended
elbow. The lateral aspect of the upper limb also experiences
loss of sensation. Chronic microtrauma to the superior trunk
of the brachial plexus from carrying a heavy backpack can
produce motor and sensory deficits in the distribution of the
musculocutaneous and radial nerves. A superior brachial
plexus injury may produce muscle spasms and a severe
disability in hikers (backpacker's palsy) who carry heavy
backpacks for long periods.

• Acute brachial plexus neuritis (brachial plexus
neuropathy) is a neurologic disorder of unknown cause
that is characterized by the sudden onset of severe
pain, usually around the shoulder. Typically, the pain
begins at night and is followed by muscle weakness and
sometimes muscular atrophy (neurologic amyotrophy).
• Inflammation of the brachial plexus (brachial neuritis) is
often preceded by some event (e.g., upper respiratory
infection, vaccination, or non-specific trauma). The
nerve fibers involved are usually derived from the
superior trunk of the brachial plexus.

• Compression of cords of the brachial plexus may result from prolonged
hyperabduction of the arm during performance of manual tasks over the head,
such as painting a ceiling. The cords are impinged or compressed between the
coracoid process of the scapula and the pectoralis minor tendon. Common
neurologic symptoms are pain radiating down the arm, numbness, paresthesia
(tingling), erythema (redness of the skin caused by capillary dilation), and weakness
of the hands. Compression of the axillary artery and vein causes ischemia of the
upper limb and distension of the superficial veins. These signs and symptoms of
hyperabduction syndrome result from compression of the axillary vessels and
nerves.
• Injuries to inferior parts of the brachial plexus (Klumpke paralysis) are much less
common. Inferior brachial plexus injuries may occur when the upper limb is
suddenly pulled superiorlyfor example, when a person grasps something to break a
fall or a baby's upper limb is pulled excessively during delivery . These events
injure the inferior trunk of the brachial plexus (C8 and T1) and may avulse the roots
of the spinal nerves from the spinal cord. The short muscles of the hand are
affected, and a claw hand results

Brachial Plexus Block
• Injection of an anesthetic solution into or immediately
surrounding the axillary sheath interrupts nerve
impulses and produces anesthesia of the structures
supplied by the branches of the cords of the plexus
Sensation is blocked in all deep structures of the upper
limb and the skin distal to the middle of the arm.
Combined with an occlusive tourniquet technique to
retain the anesthetic agent, this procedure enables
surgeons to operate on the upper limb without using a
general anesthetic.
• The brachial plexus can be anesthetized using a number
of approaches, including an interscalene,
supraclavicular, and axillary approach or block

Fractures of the Scapula
• Fractures of the scapula are usually the result
of severe trauma, such as occurs in run-over
accident victims or in occupants of automobiles
involved in crashes.
• Injuries are usually associated with fractured
ribs.
• Most fractures of the scapula require little
treatment because the muscles on the anterior
and posterior surfaces adequately splint the
fragments.

Dropped Shoulder and Winged
Scapula
The position of the scapula on the posterior wall
of the Thorax is maintained by the tone and
balance of the Muscles attached to it. If one of
these muscles is paralyzed, the balance is upset,
as in dropped shoulder, which occurs with
paralysis of the trapezius, or winged scapula,
caused by paralysis of the serratus anterior.
Such imbalance can be detected by careful
physical examination.

Fractures of the Proximal End of the Humerus
Humeral Head Fractures: Fractures of the humeral head can occur during the process of
anterior and posterior dislocations of the shoulder joint. The fibrocartilaginous glenoid labrum
of the scapula produces the fracture, and the labrum can become jammed in the defect, making
reduction of the shoulder joint difficult.
Greater Tuberosity Fractures: The greater tuberosity of the humerus can be fractured by direct
trauma, displaced by the glenoid labrum during dislocation of the shoulder joint, or avulsed by
violent contractions of the supraspinatus muscle. The bone fragment will have the attachments
of the supraspinatus, teres minor, and infraspinatus muscles, whose tendons form part of the
rotator cuff. When associated with a shoulder dislocation, severe tearing of the cuff with the
fracture can result in the greater tuberosity remaining displaced posteriorly after the shoulder
joint has been reduced. In this situation, open reduction of the fracture is necessary to attach
the rotator cuff back into place.
Lesser Tuberosity Fractures : Occasionally, a lesser tuberosity fracture accompanies posterior
dislocation of the shoulder joint. The bone fragment receives the insertion of the subscapularis
tendon , a part of the rotator cuff.
Surgical Neck Fractures: The surgical neck of the humerus, which lies immediately distal to the
lesser tuberosity, can be fractured by a direct blow on the lateral aspect of the shoulder or in an
indirect manner by falling on the outstretched hand.

Fractures of the Humerus
• Most injuries of the proximal end of the humerus are fractures of
the surgical neck.
– These injuries are especially common in elderly people with
osteoporosis, whose demineralized bones are brittle.
• Humeral fractures are often result in one fragment being driven into the spongy
bone of the other fragment (impacted fracture).
– The injuries usually result from a minor fall on the hand, with the force
being transmitted up the forearm bones of the extended limb. Because
of impaction of the fragments, the fracture site is sometimes stable and
the person is able to move the arm passively with little pain.
• An avulsion fracture of the greater tubercle of the humerus
(pulling the tubercle away from the humeral head) is seen most
commonly in middle-aged and elderly people. The fracture usually
results from a fall on the acromion, the point of the shoulder.
• In younger people, an avulsion fracture of the greater tubercle
usually results from a fall on the hand when the arm is abducted.
Muscles (especially the subscapularis) that remain attached to the
humerus pull the limb into medial rotation.

Bicipital Myotatic Reflex
• The biceps reflex is one of several deep-tendon reflexes that
are routinely tested during physical examination. The relaxed
limb is passively pronated and partially extended at the
elbow. The examiner's thumb is firmly placed on the biceps
tendon, and the reflex hammer is briskly tapped at the base
of the nail bed of the examiner's thumb. A normal (positive)
response is an involuntary contraction of the biceps, felt as a
momentarily tensed tendon, usually with a brief jerk-like
flexion of the elbow.
• A positive response confirms the integrity of the
musculocutaneous nerve and the C5 and C6 spinal cord
segments. Excessive, diminished, or prolonged (hung)
responses may indicate central or peripheral nervous system
disease or metabolic disorders (e.g., thyroid disease).

Biceps Tendinitis
• The tendon of the long head of the biceps is
enclosed by a synovial sheath and moves back and
forth in the inter-tubercular groove of the humerus.
Wear and tear of this mechanism can cause
shoulder pain. Inflammation of the tendon (biceps
tendinitis), usually the result of repetitive
microtrauma, is common in sports involving
throwing (e.g., baseball and cricket) and use of a
racquet (e.g., tennis). A tight, narrow, and/or rough
intertubercular groove may irritate and inflame the
tendon, producing tenderness and crepitus (a
crackling sound).

Dislocation of the Tendon of the Long
Head of the Biceps
• The tendon of the long head of the biceps can be
partially or completely dislocated from the
intertubercular groove in the humerus.
• This painful condition may occur in young persons
during traumatic separation of the proximal
epiphysis of the humerus.
• The injury also occurs in older persons with a
history of biceps tendinitis. Usually a sensation of
popping or catching is felt during arm rotation.

Rupture of the Tendon of the Long
Head of the Biceps
• Rupture of the tendon usually results from wear and tear of
an inflamed tendon as it moves back and forth in the
intertubercular groove of the humerus. This injury usually
occurs in individuals > 35 years of age. Typically, the tendon is
torn from its attachment to the supraglenoid tubercle of the
scapula. The rupture is commonly dramatic and is associated
with a snap or pop. The detached muscle belly forms a ball
near the center of the distal part of the anterior aspect of the
arm (Popeye deformity). Rupture of the biceps tendon may
result from forceful flexion of the arm against excessive
resistance, as occurs in weight lifters. However, the tendon
ruptures more often as the result of prolonged tendinitis that
weakens it. The rupture results from repetitive overhead
motions, such as occurs in swimmers and baseball pitchers,
which tear the weakened tendon where it passes through the
intertubercular groove.

Fracture of the shaft of the humerus
• A transverse fracture of the shaft of the humerus frequently results from a
direct blow to the arm. The pull of the deltoid muscle carries the proximal
fragment laterally . Indirect injury resulting from a fall on the outstretched
hand may produce a spiral fracture of the humeral shaft. Overriding of the
oblique ends of the fractured bone may result in foreshortening. Because
the humerus is surrounded by muscles and has a well-developed
periosteum, the bone fragments usually unite well. An intercondylar
fracture of the humerus results from a severe fall on the flexed elbow. The
olecranon of the ulna is driven like a wedge between the medial and lateral
parts of the condyle, separating one or both parts from the humeral shaft.
• The following parts of the humerus are in direct contact with the indicated
nerves:
1. Surgical neck: axillary nerve.
2. Radial groove: radial nerve.
3. Distal end of humerus: median nerve.
4. Medial epicondyle: ulnar nerve.

Fracture Dislocation of the Proximal
Humeral Epiphysis
• A direct blow or indirect injury of the shoulder of a
child or adolescent may produce a fracture
dislocation of the proximal humeral epiphysis
because the joint capsule of the glenohumeral
joint, reinforced by the rotator cuff (tendons of the
SITS muscles), is stronger than the epiphysial plate.
In severe fractures, the shaft of the humerus is
markedly displaced, but the humeral head retains
its normal relationship with the glenoid cavity of
the scapula

Fractures of the Shaft of the Humerus
Fractures of the humeral shaft are common; displacement of
the fragments depends on the relation of the site of fracture to
the insertion of the deltoid muscle. When the fracture
line is proximal to the deltoid insertion, the proximal fragment
is adducted by the pectoralis major, latissimus dorsi, and teres
major muscles; the distal fragment is pulled proximally by the
deltoid, biceps, and triceps. When the fracture is distal to the
deltoid insertion, the proximal fragment is abducted by the
deltoid, and the distal fragment is pulled proximally by the
Biceps and triceps. The radial nerve can be damaged where it
lies in the spiral groove on the posterior surface of the humerus
Under cover of the triceps muscle.

Fracture of the Humeral Shaft
• A midhumeral fracture may injure the radial nerve in
the radial groove in the humeral shaft. When this nerve
is damaged, the fracture is not likely to paralyze the
triceps because of the high origin of the nerves to two
of its three heads. A fracture of the distal part of the
humerus, near the supraepicondylar ridges, is called a
supraepicondylar fracture. The distal bone fragment
may be displaced anteriorly or posteriorly. The actions
of the brachialis and triceps tend to pull the distal
fragment over the proximal fragment, shortening the
limb. Any of the nerves or branches of the brachial
vessels related to the humerus may be injured by a
displaced bone fragment.

Fractures of the Distal End of the Humerus
Supracondylar fractures are common in children and occur when the
child falls on the outstretched hand with the elbow partially flexed.
Injuries to the median, radial, and ulnar nerves are not uncommon,
although function usually Quickly returns after reduction of the fracture.
Damage to or pressure on the brachial artery can occur at the time of
the fracture or from swelling of the surrounding tissues; the circulation
to the forearm may be interfered with, leading to Volkmann’s ischemic
contracture .
The medial epicondyle can be avulsed by the medial collateral ligament
of the elbow joint if the forearm is forcibly abducted. The ulnar nerve
can be injured at the time of the fracture, can become involved later in
the repair process of the fracture (in the callus), or can undergo
irritation on the irregular bony surface after the bone fragments are
areunited.

Absent Pectoralis Major
Occasionally, parts of the pectoralis
major muscle may be absent. The
sternocostal origin is the most
commonly missing part, and this
causes weakness in adduction and
medial rotation of the shoulder joint.

Absence of the Pectoral Muscles
• Absence of part of the pectoralis major, usually its
sternocostal part, is uncommon, but when it occurs,
no disability usually results. However, the anterior
axillary fold, formed by the skin and fascia overlying
the inferior border of the pectoralis major, is absent
on the affected side, and the nipple is more inferior
than usual. In Poland syndrome, both the pectoralis
major and minor are absent; breast hypoplasia and
absence of two to four rib segments are also seen.

Paralysis of the Serratus Anterior
• When the serratus anterior is paralyzed owing to injury to the long
thoracic nerve, the medial border of the scapula moves laterally
and posteriorly away from the thoracic wall, giving the scapula the
appearance of a wing, especially when the person leans on a hand
or presses the upper limb against a wall. When the arm is raised,
the medial border and inferior angle of the scapula pull markedly
away from the posterior thoracic wall, a deformation known as a
winged scapula.
• In addition, the upper limb cannot be abducted above the
horizontal position because the serratus anterior is unable to
rotate the glenoid cavity superiorly to allow complete abduction of
the limb. Although protected when the limbs are at one's sides,
the long thoracic nerve is exceptional in that it courses on the
superficial aspect of the serratus anterior, which it supplies. Thus
when the limbs are elevated, as in a knife fight, the nerve is
especially vulnerable. Weapons, including bullets directed toward
the thorax, are a common source ofinjury.

Triangle of Auscultation
• Near the inferior angle of the scapula is a small
triangular gap in the musculature. The superior
horizontal border of the latissimus dorsi, the medial
border of the scapula, and the inferolateral border
of the trapezius form a triangle of auscultation.
• This gap in the thick back musculature is a good
place to examine posterior segments of the lungs
with a stethoscope. When the scapulae are drawn
anteriorly by folding the arms across the chest and
the trunk is flexed, the auscultatory triangle
enlarges and parts of the 6th and 7th ribs and 6th
intercostal space are subcutaneous.

Compression of the Axillary Artery
• The axillary artery can be palpated in the inferior
part of the lateral wall of the axilla. Compression of
the third part of this artery against the humerus
may be necessary when profuse bleeding occurs
(e.g., resulting from a stab or bullet wound in the
axilla). If compression is required at a more
proximal site, the axillary artery can be compressed
at its origin (as the subclavian artery crosses the 1st
rib) by exerting downward pressure in the angle
between the clavicle and the inferior attachment of
the sternocleidomastoid.

Arterial Anastomoses around the
Scapula
• Many arterial anastomoses (communications between arteries) occur around the
scapula. Several vessels join to form networks on the anterior and posterior
surfaces of the scapula: the dorsal scapular, suprascapular, and (via the circumflex
scapular) subscapular arteries. The importance of the collateral circulation made
possible by these anastomoses becomes apparent when ligation of a lacerated
subclavian or axillary artery is necessary. For example, the axillary artery may have
to be ligated between the 1st rib and subscapular artery; in other cases, vascular
stenosis (narrowing) of the axillary artery may result from an atherosclerotic lesion
that causes reduced blood flow. In either case, the direction of blood flow in the
subscapular artery is reversed, enabling blood to reach the third part of the axillary
artery. Note that the subscapular artery receives blood through several
anastomoses with the suprascapular artery, transverse cervical artery, and
intercostal arteries.
• Slow occlusion of the axillary artery (e.g., resulting from disease or trauma) often
enables sufficient collateral circulation to develop, preventing ischemia. Sudden
occlusion usually does not allow sufficient time for adequate collateral circulation
to develop; as a result, there is an inadequate supply of blood to the arm, forearm,
and hand. While potential collateral pathways (periarticular anastomoses) exist
around the shoulder joint proximally and the elbow joint distally, surgical ligation of
the axillary artery between the origins of the subscapular artery and the deep
artery of the arm will cut off the blood supply to the arm because the collateral
circulation is inadequate.

Aneurysm of the Axillary Artery
• The first part of the axillary artery may enlarge
(aneurysm of the axillary artery) and
compress the trunks of the brachial plexus,
causing pain and anesthesia (loss of
sensation) in the areas of the skin supplied by
the affected nerves. Aneurysm of the axillary
artery may occur in baseball pitchers because
of their rapid and forceful arm movements

Spontaneous Thrombosis of the
Axillary Vein
Spontaneous thrombosis of the
axillary vein occasionally occurs
after excessive and unaccustomed
movements of the arm at the
shoalder joint.

Interruption of Blood Flow in the
Brachial Artery
• Stopping bleeding through manual or surgical control of blood flow is
hemostasis. The best place to compress the brachial artery to control
hemorrhage is medial to the humerus near the middle of the arm . Because
the arterial anastomoses around the elbow provide a functionally and
surgically important collateral circulation, the brachial artery may be
clamped distal to the origin of the deep artery of the arm without
producing tissue damage. The anatomical basis for this procedure is that
the ulnar and radial arteries will still receive sufficient blood through the
anastomoses around the elbow. Although collateral pathways confer some
protection against gradual temporary and partial occlusion, sudden
complete occlusion or laceration of the brachial artery creates a surgical
emergency because paralysis of muscles results from ischemia of the elbow
and forearm within a few hours. Muscles and nerves can tolerate up to 6
hours of ischemia; after this, fibrous scar tissue replaces necrotic tissue and
causes the involved muscles to shorten permanently, producing a flexion
deformity, the ischemic compartment syndrome (Volkmann or ischemic
contracture). Contraction of the fingers and sometimes the wrist results in
loss of hand power as a result of irreversible necrosis of the forearm flexor
muscles.

Injuries to the Axillary Vein
• Wounds in the axilla often involve the axillary vein
because of its large size and exposed position.
When the arm is fully abducted, the axillary vein
overlaps the axillary artery anteriorly.
• A wound in the proximal part of the axillary vein is
particularly dangerous, not only because of profuse
bleeding but also because of the risk of air entering
it and producing air emboli (air bubbles) in the
blood.

The Role of the Axillary Vein in
Subclavian Vein Puncture
• Subclavian vein puncture, in which a catheter is placed
into the subclavian vein, has become a common clinical
procedure . The axillary vein becomes the subclavian
vein as the first rib is crossed. Because the needle is
advanced medially to enter the vein as it crosses the
rib, the vein actually punctured (the point of entry) in
subclavian vein puncture is the terminal part of the
axillary vein. However, the needle tip proceeds into the
lumen of the subclavian vein almost immediately. Thus
it is clinically significant that the axillary vein lies
anterior and inferior (i.e., superficial) to the axillary
artery and the parts of the brachial plexus that begin to
surround the artery at this point.

The Axillary Sheath and a Brachial
Plexus Nerve Block
Because the axillary sheath encloses the axillary vessels and
the brachial plexus, a brachial plexus nerve block can easily
be obtained. The distal part of the sheath is closed with
finger pressure, and a syringe needle is inserted into the
proximal part of the sheath. The anesthetic solution is then
injected into the sheath, and the solution is massaged along
the sheath to produce the nerve block. The position of the
sheath can be verified by feeling the pulsations of the third
part of the axillary artery.

Examination of the Axillary Lymph Nodes
With the patient standing or sitting, he or she is asked to place the hand of the side to
be examined on the hip and push hard medially. This action of adduction of the
shoulder joint causes the pectoralis major muscle to contract maximally so that it
becomes hard like a board. The examiner then palpates the axillary nodes as follows:
■■ The anterior (pectoral) nodes may be palpated by pressing forward against the
posterior surface of the pectoralis major muscle on the anterior wall of the axilla.
■■ The posterior (subscapular) nodes may be palpated by pressing backward against
the anterior surface of the subscapularis muscle on the posterior wall of the axilla.
■■ The lateral nodes may be palpated against the medial side of the axillary vein. The
xaminer’s fingers are pressed laterally against the subclavian vein and the pulsating
axillary artery.
■■ The central nodes may be palpated in the center of the axilla between the
pectoralis major (anterior wall) and the subscapularis (posterior wall).
■■ For the apical nodes, the patient is asked to relax the shoulder muscles and let
the upper limb hang down at the side. The examiner then gently places the tips of the
fingers of the examining hand high up in the axilla to the outer border of the first rib.
If the nodes are enlarged, they can be felt. The examination of the axillary lymph
nodes always forms part of the clinical examination of the breast.

Rotator Cuff Tendinitis
The rotator cuff, consisting of the tendons of the subscapularis, supraspinatus, infraspinatus, and teres minor
muscles, which are fused to the underlying capsule of the shoulder joint, plays an important role in
stabilizing the shoulder joint.
The rotator cuff presses the humeral head into the glenoid cavity. Lesions of the cuff are a common cause of
pain in the shoulder region. Failure of the cuff is due to either wear or tear. Wear is age related. Excessive
overhead activity of the upper limb may be the cause of tendinitis, although many cases appear
spontaneously. During abduction of the shoulder joint, the supraspinatus tendon is exposed to friction
against the acromion .
Under normal conditions, the amount of friction is reduced to a minimum by the large subacromial bursa,
which extends laterally beneath the deltoid. Degenerative changes in the bursa are followed by degenerative
changes in the underlying supraspinatus tendon, and these may extend into the other tendons of the rotator
cuff. Clinically, the condition is known as subacromial bursitis, supraspinatus tendinitis, or pericapsulitis. It
is characterized by the presence of a spasm of pain in the middle range of abduction, when the diseased
area impinges on the acromion. Extensive acute traumatic tears are best repaired surgically as soon as
possible. Small chronic cuff injuries are best managed without surgery using nonsteroidal anti-inflammatory
drugs and muscle exercises.

Rupture of the Supraspinatus Tendon
In advanced cases of rotator cuff tendinitis, the necrotic
supraspinatus tendon can become calcified or rupture. Rupture
of the tendon seriously interferes with the normal abduction
movement of the shoulder joint. It will be remembered that
the main function of the supraspinatus muscle is to hold the
head of the humerus in the glenoid fossa at the
commencement
of abduction. The patient with a ruptured supraspinatus
tendon is unable to initiate abduction of the arm. However, if
the arm is passively assisted for the first 15° of abduction, the
deltoid can then take over and complete the movement to a
right angle.

Axillary Nerve Injury
The axillary nerve can be
injured in dislocations of
the shoulder joint.

Axillary Nerve Injury
• The axillary nerve may be injured when the
glenohumeral joint dislocates because of its close
relation to the inferior part of the joint capsule of
this joint. The subglenoid displacement of the head
of the humerus into the quadrangular space
damages the axillary nerve. Axillary nerve injury is
indicated by paralysis of the deltoid (manifest as an
inability to abduct the arm to or above the
horizontal level) and loss of sensation in a small
area of skin covering the central part of the deltoid.

Injury to the Axillary Nerve
• The deltoid atrophies when the axillary nerve (C5 and C6) is
severely damaged. Because it passes inferior to the humeral head
and winds around the surgical neck of the humerus, the axillary
nerve is usually injured during fracture of this part of the humerus.
It may also be damaged during dislocation of the glenohumeral
joint and by compression from the incorrect use of crutches. As
the deltoid atrophies, the rounded contour of the shoulder
disappears. This gives the shoulder a flattened appearance and
produces a slight hollow inferior to the acromion. In addition to
atrophy of the deltoid, a loss of sensation may occur over the
lateral side of the proximal part of the arm, the area supplied by
the superior lateral cutaneous nerve of the arm.
• The deltoid is a common site for the intramuscular injection of
drugs. The axillary nerve runs transversely under cover of the
deltoid at the level of the surgical neck of the humerus. Awareness
of its location avoids injury to it during surgical approaches to the
shoulder.

Rotator Cuff Injuries
• The musculotendinous rotator cuff is commonly injured during repetitive use of the upper
limb above the horizontal (e.g., during throwing and racquet sports, swimming, and
weightlifting). Recurrent inflammation of the rotator cuff, especially the relatively avascular
area of the supraspinatus tendon, is a common cause of shoulder pain and results in tears of
the musculotendinous rotator cuff. Repetitive use of the rotator cuff muscles (e.g., by
baseball pitchers) may allow the humeral head and rotator cuff to impinge on the
coracoacromial arch, producing irritation of the arch and inflammation of the rotator cuff. As
a result, degenerative tendonitis of the rotator cuff develops. Attrition of the supraspinatus
tendon also occurs.
• To test for degenerative tendonitis of the rotator cuff, the person is asked to lower the fully
abducted limb slowly and smoothly. From approximately 90Â° abduction, the limb will
suddenly drop to the side in an uncontrolled manner if the rotator cuff (especially the
supraspinatus part) is diseased and/or torn.
• Rotator cuff injuries can also occur during a sudden strain of the muscles, for example, when
an older person strains to lift something, such as a window sash that is stuck, a previously
degenerated musculotendinous rotator cuff may rupture. A fall on the shoulder may also
tear a previously degenerated rotator cuff. Often the intracapsular part of the tendon of the
long head of the biceps brachii becomes frayed (even worn away) leaving it adherent to the
intertubercular groove. As a result, shoulder stiffness occurs. Because they fuse, the integrity
of the fibrous layer of the joint capsule of the glenohumeral joint is usually compromised
when the rotator cuff is injured. As a result, the articular cavity communicates with the
subacromial bursa. Because the supraspinatus muscle is no longer functional with a
complete tear of the rotator cuff, the person cannot initiate abduction of the upper limb. If
the arm is passively abducted 15Â° or more, the person can usually maintain or continue the
abduction using the deltoid.

Rotator Cuff Injuries and the
Supraspinatus
• Injury or disease may damage the
musculotendinous rotator cuff, producing instability
of the glenohumeral joint. Trauma may tear or
rupture one or more of the tendons of the SITS
muscles; that of the supraspinatus is most
commonly involved.
• Degenerative tendonitis of the rotator cuff is
common, especially in older people. These
syndromes are discussed in detail (later in this
chapter) in relationship to the glenohumeral joint.

Dislocation of the Glenohumeral Joint
• Because of its freedom of movement and instability, the glenohumeral joint is commonly
dislocated by direct or indirect injury. Because the presence of the coracoacromial arch and
the support of the rotator cuff are effective in preventing upward dislocation, most
dislocations of the humeral head occur in the downward (inferior) direction. However, they
are described clinically as anterior or (more rarely) posterior dislocations, indicating whether
the humeral head has descended anterior or posterior to the infraglenoid tubercle and the
long head of the triceps. The head ends up lying anterior or posterior to the glenoid cavity.
• Anterior dislocation of the glenohumeral joint occurs most often in young adults, particularly
athletes. It is usually caused by excessive extension and lateral rotation of the humerus .
• The head of the humerus is driven inferoanteriorly, and the fibrous layer of the joint capsule
and glenoid labrum may be stripped from the anterior aspect of the glenoid cavity in the
process. A hard blow to the humerus when the glenohumeral joint is fully abducted tilts the
head of the humerus inferiorly onto the inferior weak part of the joint capsule. This may tear
the capsule and dislocate the shoulder so that the humeral head comes to lie inferior to the
glenoid cavity and anterior to the infraglenoid tubercle. The strong flexor and adductor
muscles of the glenohumeral joint usually subsequently pull the humeral head
anterosuperiorly into a subcoracoid position. Unable to use the arm, the person commonly
supports it with the other hand. Inferior dislocation of the glenohumeral joint often occurs
after an avulsion fracture of the greater tubercle, owing to the absence of the upward and
medial pull produced by the muscles attaching to the tubercle.

Glenoid Labrum Tears
• Tearing of the fibrocartilaginous glenoid labrum
commonly occurs in athletes who throw a baseball or
football and in those who have shoulder instability and
subluxation (partial dislocation) of the glenohumeral
joint. The tear often results from sudden contraction of
the biceps or forceful subluxation of the humeral head
over the glenoid labrum. Usually a tear occurs in the
anterosuperior part of the labrum. The typical
symptom is pain while throwing, especially during the
acceleration phase, but a sense of popping or snapping
may be felt in the glenohumeral joint during abduction
and lateral rotation of the arm.

Adhesive Capsulitis of the
Glenohumeral Joint
• Adhesive fibrosis and scarring between the inflamed joint
capsule of the glenohumeral joint, rotator cuff, subacromial
bursa, and deltoid usually cause adhesive capsulitis , a
condition seen in individuals 60 years of age. A person with
this condition has difficulty abducting the arm and can
obtain an apparent abduction of up to 45Â° by elevating
and rotating the scapula. Because of the lack of movement
of the glenohumeral joint, strain is placed on the AC joint,
which may be painful during other movements (e.g.,
elevation, or shrugging, of the shoulder). Injuries that may
initiate acute capsulitis are glenohumeral dislocations,
calcific supraspinatus tendinitis, partial tearing of the
rotator cuff, and bicipital tendinitis

Accessory Nerve Injury
The accessory nerve can be injured as the result
of stab wounds to the neck.

Injury of the Accessory Nerve (CN XI)
• The primary clinical manifestation
of accessory nerve palsy is a
marked ipsilateral weakness
when the shoulders are elevated
(shrugged) against resistance.

Injury of the Thoracodorsal Nerve
• Surgery in the inferior part of the axilla puts the thoracodorsal
nerve supplying the latissimus dorsi at risk of injury. This nerve
passes inferiorly along the posterior wall of the axilla and enters
the medial surface of the latissimus dorsi close to where it
becomes tendinous . The nerve is also vulnerable to injury during
surgery on scapular lymph nodes because its terminal part lies
anterior to them and the subscapular artery. The latissimus dorsi
and the inferior part of the pectoralis major form an
aanteroposterior muscular sling between the trunk and the arm;
however, the latissimus dorsi forms the more powerful part of the
sling. With paralysis of the latissimus dorsi, the person is unable to
raise the trunk with the upper limbs, as occurs during climbing.
Furthermore, the person cannot use an axillary crutch because the
shoulder is pushed superiorly by it. These are the primary
activities for which active depression of the scapula is required;
the passive depression provided by gravity is adequate for most
activities.

Injury to the Dorsal Scapular Nerve
• Injury to the dorsal scapular nerve, the nerve
to the rhomboids, affects the actions of these
muscles. If the rhomboids on one side are
paralyzed, the scapula on the affected side is
located farther from the midline than that on
the normal side.

Arterial Anastomosis and Ligation of
the Axillary Artery
The existence of the anastomosis
around the shoulder joint is vital to
preserving the upper limb should it
be necessary to ligate the axillary
artery.

Sternoclavicular Joint Injuries
The strong costoclavicular ligament firmly holds the medial end of the
clavicle to the 1st costal cartilage. Violent forces directed along the long
axis of the clavicle usually result in fracture of that bone, but dislocation
of the sternoclavicular joint takes place occasionally.
Anterior dislocation results in the medial end of the clavicle projecting
forward beneath the skin; it may also be pulled upward by the
sternocleidomastoid muscle.
Posterior dislocation usually follows direct trauma applied to the front
of the joint that drives the clavicle backward. This type is the more
serious one because the displaced clavicle may
press on the trachea, the esophagus, and major blood vessels in the
root of the neck.
If the costoclavicular ligament ruptures completely, it is difficult to
maintain the normal position of the clavicle once reduction has been
accomplished.

Acromioclavicular Joint Injuries
The plane of the articular surfaces of the acromioclavicular
joint passes downward and medially so that there is a
tendency for the lateral end of the clavicle to ride up over the
upper surface of the acromion.
The strength of the joint depends on the strong racoclavicular
ligament, which binds the coracoid process to the ndersurface
of the lateral part of the clavicle. The greater part of the
weight of the upper limb is transmitted to the clavicle through
this ligament, and rotary movements of the scapula occur at
this important ligament.

Acromioclavicular Dislocation
A severe blow on the point of the shoulder, as is
incurred during blocking or tackling in football or any
severe fall, can result in the acromion being thrust
beneath the lateral end of the clavicle, tearing the
coracoclavicular ligament. This condition is known as
shoulder separation. The displaced outer end of
the clavicle is easily palpable. As in the case of the
sternoclavicular joint, the dislocation is easily
reduced, but withdrawal of support results in
immediate redislocation.

Stability of the Shoulder Joint
The shallowness of the glenoid fossa of the scapula and the lack
of support provided by weak ligaments make this joint an
unstable structure. Its strength almost entirely depends on the
tone of the short muscles that bind the upper end of the
humerus to the scapula—namely, the subscapularis in front, the
supraspinatus above, and the infraspinatus and teres minor
behind. The tendons of these muscles are fused to the underlying
capsule of the shoulder joint. Together, these tendons form the
rotator cuff.
The least supported part of the joint lies in the inferior location,
where it is unprotected by muscles.

Dislocations of the Shoulder Joint
The shoulder joint is the most commonly dislocated large joint.
Anterior Inferior Dislocation
Sudden violence applied to the humerus with the joint fully abducted tilts the humeral
head downward onto the inferior weak part of the capsule, which tears, and the
humeral head comes to lie inferior to the glenoid fossa. During this movement, the
acromion has acted as a fulcrum. The strong flexors and adductors of the shoulder
joint now usually pull the humeral head forward and upward into the subcoracoid
position.
Posterior Dislocations
Posterior dislocations are rare and are usually caused by direct violence to the front of
the joint. On inspection of the patient with shoulder dislocation, the rounded
appearance of the shoulder is seen to be lost because the greater tuberosity of the
humerus is no longer bulging laterally beneath the deltoid muscle. A subglenoid
displacement of the head of the humerus into the quadrangular space can cause
damage to the axillary nerve, as indicated by paralysis of the deltoid muscle and loss of
skin sensation over the lower half of the deltoid. Downward displacement of the
humerus can also stretch and damage the radial nerve.

Shoulder Pain
The synovial membrane, capsule, and ligaments of the shoulder joint
are innervated by the axillary nerve and the suprascapular nerve. The
joint is sensitive to pain, pressure, excessive traction, and distention.
The muscles surrounding the joint undergo reflex spasm in response
to pain originating in the joint, which in turn serves to immobilize the
joint and thus reduce the pain.
Injury to the shoulder joint is followed by pain, limitation of
movement, and muscle atrophy owing to disuse. It is important to
appreciate that pain in the shoulder region can be caused by disease
elsewhere and that the shoulder joint may be normal; for example,
diseases of the spinal cord and vertebral column and the pressure of
a cervical rib (see page XXX) can cause shoulder
pain. Irritation of the diaphragmatic pleura or peritoneum can
produce referred pain via the phrenic and supraclavicular nerves.

Dermatomes and Cutaneous Nerves
It may be necessary for a physician to test the integrity of the spinal cord
segments of C3 through T1. The diagrams in Figures 1.23 and 1.24 show the
arrangement of the dermatomes of the upper limb. It is seen that the
dermatomes for the upper cervical segments C3 to 6 are located along the
lateral margin of the upper limb; the C7 dermatome is situated on the middle
finger; and the dermatomes for C8, T1, and T2 are along the medial margin of
the limb. The nerve fibers from a particular segment of the spinal cord,
although they exit from the cord in a spinal nerve of the same segment, pass
to the skin in two or more different cutaneous nerves.
The skin over the point of the shoulder and halfway down the lateral surface of
the deltoid muscle is supplied by the supraclavicular nerves (C3 and 4). Pain
may be referred to this region as a result of inflammatory lesions involving the
diaphragmatic pleura or peritoneum. The afferent stimuli reach the spinal cord
via the phrenic nerves (C3, 4, and 5). Pleurisy, peritonitis, subphrenic abscess,
or gallbladder disease may therefore be responsible for shoulder pain.

High Division of the Brachial Artery
• Sometimes the brachial artery divides at
a more proximal level than usual. In this
case, the ulnar and radial arteries begin
in the superior or middle part of the arm,
and the median nerve passes between
them

Superficial Ulnar Artery
• In approximately 3% of people, the ulnar artery
descends superficial to the flexor muscles.
Pulsations of a superficial ulnar artery can be felt
and may be visible. This variation must be kept in
mind when performing venesections for
withdrawing blood or making intravenous
injections. If an aberrant ulnar artery is mistaken for
a vein, it may be damaged and produce bleeding. If
certain drugs are injected into the aberrant artery,
the result could be fatal

Venipuncture and Blood Transfusion
The superficial veins are clinically important and are used for venipuncture,
transfusion, and cardiac catheterization. Every clinical professional, in an
emergency, should know where to obtain blood from the arm. When a patient
is in a state of shock, the superficial veins are not always visible. The cephalic
vein lies fairly constantly in the superficial fascia, immediately posterior to the
styloid process of the radius. In the cubital fossa, the median cubital vein is
separated from the underlying brachial artery by the bicipital aponeurosis. This
is important because it protects the artery from the mistaken introduction into
its lumen of irritating drugs that should have been injected into the vein.
The cephalic vein, in the deltopectoral triangle, frequently communicates
with the external jugular vein by a small vein that crosses in front of the
clavicle. Fracture of the clavicle can result in rupture of this communicating
vein, with the formation of a large hematoma.

Intravenous Transfusion and
Hypovolemic Shock
In extreme hypovolemic shock,
excessive venous tone may inhibit
venous blood flow and thus delay the
introduction of intravenous blood into
the vascular system.

Anatomy of Basilic and Cephalic Vein
Catheterization
The median basilic or basilic veins are the veins of choice for central
venous catheterization, because from the cubital fossa until the
basilic vein reaches the axillary vein, the basilic vein increases in
diameter and is in direct line with the axillary vein. The valves in the
axillary vein may be troublesome, but abduction of the shoulder joint
may permit the catheter to move past the obstruction.
The cephalic vein does not increase in size as it ascends the arm,
and it frequently divides into small branches as it lies within the
deltopectoral triangle. One or more of these branches may ascend
over the clavicle and join the external jugular vein. In its usual
method of termination, the cephalic vein joins the axillary vein at a
right angle. It may be difficult to maneuver the catheter around this
angle.

Measuring the Pulse Rate
• The common place for measuring the pulse rate is
where the radial artery lies on the anterior surface of
the distal end of the radius, lateral to the tendon of the
FCR. Here the artery is covered by only fascia and skin.
The artery can be compressed against the distal end of
the radius, where it lies between the tendons of the
FCR and APL. When measuring the radial pulse rate, the
pulp of the thumb should not be used because it has its
own pulse, which could obscure the patient's pulse. If a
pulse cannot be felt, try the other wrist because an
aberrant radial artery on one side may make the pulse
difficult to palpate. A radial pulse may also be felt by
pressing lightly in the anatomical snuff box.

Variations in the Origin of the Radial
Artery
• The origin of the radial artery may be more
proximal than usual; it may be a branch of the
axillary artery or the brachial artery.
• Sometimes the radial artery is superficial to the
deep fascia instead of deep to it. When a superficial
vessel is pulsating near the wrist, it is probably a
superficial radial artery. The aberrant vessel is
vulnerable to laceration

Venipuncture in the Cubital Fossa
• The cubital fossa is the common site for sampling and transfusion
of blood and intravenous injections because of the prominence
and accessibility of veins. Usually, the median cubital vein or
basilic vein is selected. The median cubital vein lies directly on
the deep fascia, crossing the bicipital aponeurosis, which
separates it from the underlying brachial artery and median
nerve and provides some protection to the latter. Historically,
during the days of bloodletting, the bicipital aponeurosis was
known as the grace Deux (Fr. grace of God) tendon, by the grace
of which arterial hemorrhage was usually avoided. A tourniquet
is placed around the midarm to distend the veins in the cubital
fossa. Once the vein is punctured, the tourniquet is removed so
that when the needle is removed the vein will not bleed
extensively. The cubital veins are also a site for the introduction
of cardiac catheters to secure blood samples from the great
vessels and chambers of the heart. These veins may also used for
cardioangiography

Variation of Veins in the Cubital Fossa
• The pattern of veins in the cubital fossa varies greatly. In
approximately 20% of people, the median antebrachial vein
(median vein of the forearm) divides into a median basilic vein,
which joins the basilic vein. and a median cephalic vein, which
joins the cephalic vein. In these cases, a clear M formation is
produced by the cubital veins. It is important to observe and
remember that either the median cubital vein or the median
basilic vein, whichever pattern is present, crosses superficial to
the brachial artery, from which it is separated by the bicipital
aponeurosis. These veins are good sites for drawing blood but
are not ideal for injecting an irritating drug because of the
danger of injecting it into the brachial artery. In obese people,
a considerable amount of fatty tissue may overlie the vein.

Dermatomes and Cutaneous Nerves
It may be necessary for a physician to test the integrity of the spinal cord segments of
C3 through T1. It is seen that the dermatomes for the upper cervical segments C3 to 6
are located along the lateral margin of the upper limb; the C7 dermatome is situated
on the middle finger; and the dermatomes for C8, T1, and T2 are along the medial
margin of the limb. The nerve fibers from a particular segment of the spinal cord,
although they exit from the cord in a spinal nerve of the same segment, pass to the
skin in two or more different cutaneous nerves.
The skin over the point of the shoulder and halfway down the lateral surface of the
deltoid muscle is supplied by the supraclavicular nerves (C3 and 4). Pain may be
referred to this region as a result of inflammatory lesions involving the diaphragmatic
pleura or peritoneum. The afferent stimuli reach the spinal cord via the phrenic nerves
(C3, 4, and 5). Pleurisy, peritonitis, subphrenic abscess, or gallbladder disease may
therefore be responsible for shoulder pain.

Lymphangitis
Infection of the lymph vessels (lymphangitis) of the arm is
common. Red streaks along the course of the lymph vessels
are characteristic of the condition. The lymph vessels from
the thumb and index finger and the lateral part of the hand
follow the cephalic vein to the infraclavicular group of axillary
nodes; those from the middle, ring, and little fingers and
from the medial part of the hand follow the basilic vein to the
supratrochlear node, which lies in the superficial fascia just
above the medial epicondyle of the humerus, and thence to
the lateral group of axillary nodes.

Lymphadenitis
Once the infection reaches the lymph nodes, they
become enlarged and tender, a condition known as
lymphadenitis.
Most of the lymph vessels from the fingers and palm
pass to the dorsum of the hand before passing up into
the forearm. This explains the frequency of
inflammatory edema, or even abscess formation,
which may occur on the dorsum of the hand after
infection of the fingers or palm.

Enlargement of the Axillary Lymph
Nodes
• An infection in the upper limb can cause the axillary
nodes to enlarge and become tender and inflamed, a
condition called lymphangitis (inflammation of
lymphatic vessels). The humeral group of nodes is
usually the first to be involved. Lymphangitis is
characterized by the development of warm, red, tender
streaks in the skin of the limb. Infections in the pectoral
region and breast, including the superior part of the
abdomen, can also produce enlargement of axillary
nodes. In metastatic cancer of the apical group, the
nodes often adhere to the axillary vein, which may
necessitate excision of part of this vessel. Enlargement
of the apical nodes may obstruct the cephalic vein
superior to the pectoralis minor.

Dissection of the Axillary Lymph Nodes
• Excision and pathologic analysis of axillary lymph nodes are often necessary
for staging and determining the appropriate treatment of a cancer such as
breast cancer (see Chapter 1). Because the axillary lymph nodes are
arranged and receive lymph (and therefore metastatic breast cancer cells) in
a specific order, removing and examining the lymph nodes in that order is
important in determining the degree to which the cancer has developed
and is likely to have metastasized. Lymphatic drainage of the upper limb
may be impeded after the removal of the axillary nodes, resulting in
lymphedema, swelling as a result of accumulated lymph, especially in the
subcutaneous tissue.
• During axillary node dissection, two nerves are at risk of injury. During
surgery, the long thoracic nerve to the serratus anterior is identified and
maintained against the thoracic wall. As discussed earlier in this chapter,
cutting the long thoracic nerve results in a winged scapula. If the
thoracodorsal nerve to the latissimus dorsi is cut, medial rotation and
adduction of the arm are weakened, but deformity does not result. If the
nodes around this nerve are obviously malignant, sometimes the nerve has
to be sacrificed as the nodes are resected to increase the likelihood of
complete removal of all malignant cells.

Biceps Brachii and Osteoarthritis of
the Shoulder Joint
The tendon of the long head of biceps is
attached to the supraglenoid tubercle
within the shoulder joint. Advanced
osteoarthritic changes in the joint can lead
to erosion and fraying of the tendon by
osteophytic outgrowths, and rupture of the
tendon can occur.

Fractures of the Radius and Ulna
Fractures of the head of the radius can occur from falls on the outstretched hand. As the force is
transmitted along the radius, the head of the radius is driven sharply against the capitulum, splitting or
splintering the head . Fractures of the neck of the radius occur in young children from falls on the
outstretched hand .
Fractures of the shafts of the radius and ulna may or may not occur together. Displacement of the
fragments is usually considerable and depends on the pull of the attached muscles. The proximal fragment
of the radius is supinated by the supinator and the biceps brachii muscles. The distal fragment of the radius
is pronated and pulled medially by the pronator quadratus muscle. The strength of the brachioradialis and
extensor carpi radialis longus and brevis shortens and angulates the forearm. In fractures of the ulna, the
ulna angulates posteriorly. To restore the normal movements of pronation and supination, the normal
anatomic relationship of the radius, ulna, and interosseous membrane must be regained. A fracture of one
forearm bone may be associated with a dislocation of the other bone. In Monteggia’s fracture, for example,
the shaft of the ulna is fractured by a force applied from behind. There is a bowing forward of the ulnar shaft
and an anterior dislocation of the radial head with rupture of the anular ligament. In Galeazzi’s fracture, the
proximal third of the radius is fractured and the distal end of the ulna is dislocated at the distal radioulnar
joint.
Fractures of the olecranon process can result from a fall on the flexed elbow or from a direct blow.
Depending on the location of the fracture line, the bony fragment may be displaced by the pull of the triceps
muscle, which is inserted on the olecranon process . Avulsion fractures of part of the olecranon process can
be produced by the pull of the triceps muscle. Good functional return after any of these fractures depends
on the accurate anatomic reduction of the fragment.

Elbow Tendinitis or Lateral Epicondylitis
• Elbow tendinitis (tennis elbow) is a painful
musculoskeletal condition that may follow
repetitive use of the superficial extensor muscles of
the forearm. Pain is felt over the lateral epicondyle
and radiates down the posterior surface of the
forearm. People with elbow tendinitis often feel
pain when they open a door or lift a glass. Repeated
forceful flexion and extension of the wrist strain the
attachment of the common extensor tendon,
producing inflammation of the periosteum of the
lateral epicondyle (lateral epicondylitis).

Fracture of the Olecranon
• Fracture of the olecranon, called a â€œfractured
elbowâ€•by laypersons, is common because the
olecranon is subcutaneous and protrusive. The typical
mechanism of injury is a fall on the elbow combined
with sudden powerful contraction of the triceps. The
fractured olecranon is pulled away by the active and
tonic contraction of the triceps, and the injury is often
considered to be an avulsion fracture. This is a serious
fracture requiring the services of an orthopedic
surgeon. Because of the traction produced by the tonus
of the triceps on the olecranon fragment, pinning is
usually required. Healing occurs slowly, and often a cast
must be worn for nearly a year.

Fractures of the Radius and Ulna
• Fractures of both the radius and the ulna are usually the result of severe injury. A direct injury usually produces
transverse fractures at the same level, usually in the middle third of the bones. Isolated fractures of the radius or
ulna also occur. Because the shafts of these bones are firmly bound together by the interosseous membrane, a
fracture of one bone is likely to be associated with dislocation of the nearest joint.
• Fracture of the distal end of the radius is a common fracture in adults > 50 years of age and occurs more
frequently in women because their bones are more commonly weakened by osteoporosis. A complete transverse
fracture of the distal 2 cm of the radius, called a Colles fracture, is the most common fracture of the forearm (Fig.
B6.3). The distal fragment is displaced dorsally and is often comminuted (broken into pieces). The fracture results
from forced dorsiflexion of the hand, usually as the result of trying to ease a fall by outstretching the upper limb.
Often the ulnar styloid process is avulsed (broken off). Normally the radial styloid process projects farther distally
than the ulnar styloid; consequently, when a Colles fracture occurs, this relationship is reversed because of
shortening of the radius . This clinical condition is often referred to as a dinner fork (silver fork) deformity because a
posterior angulation occurs in the forearm just proximal to the wrist and the normal anterior curvature of the
relaxed hand. The posterior bending is produced by the posterior displacement and tilt of the distal fragment of the
radius.
• The typical history of a person with a Colles fracture includes slipping or tripping and, in an attempt to break
the fall, landing on the outstretched limb with the forearm and hand pronated. Because of the rich blood supply to
the distal end of the radius, bony union is usually good.
• When the distal end of the radius fractures in children, the fracture line may extend through the distal
epiphysial plate. Epiphysial plate injuries are common in older children because of their frequent falls in which the
forces are transmitted from the hand to the radius and ulna. The healing process may result in malalignment of the
epiphysial plate and disturbance of radial growth.

Bursitis of the Elbow
• The subcutaneous olecranon bursa is exposed to injury during falls on the
elbow and to infection from abrasions of the skin covering the olecranon.
Repeated excessive pressure and friction, as occurs in wrestling, for
example, may cause this bursa to become inflamed, producing a friction
subcutaneous olecranon bursitis (e.g.student's elbow). This type of bursitis
is also known as dart thrower's elbow and miner's elbow.•Occasionally, the
bursa becomes infected and the area over the bursa becomes inflamed.
• Subtendinous olecranon bursitis is much less common. It results from
excessive friction between the triceps tendon and olecranon, for example,
resulting from repeated flexion extension of the forearm as occurs during
certain assembly-line jobs. The pain is most severe during flexion of the
forearm because of pressure exerted on the inflamed subtendinous
olecranon bursa by the triceps tendon.
• Bicipitoradial bursitis (biceps bursitis) results in pain when the forearm is
pronated because this action compresses the bicipitoradial bursa against
the anterior half of the tuberosity of the radius.

Avulsion of the Medial Epicondyle
• Avulsion of the medial epicondyle in children can result
from a fall that causes severe abduction of the
extended elbow, an abnormal movement of this
articulation. The resulting traction on the ulnar
collateral ligament pulls the medial epicondyle distally .
The anatomical basis of avulsion of the epicondyle is
that the epiphysis for the medial epicondyle may not
fuse with the distal end of the humerus until up to age
20. Usually fusion is complete radiographically at age
14 in females and age 16 in males. Traction injury of the
ulnar nerve is a frequent complication of the abduction
type of avulsion of the medial epicondyle. The
anatomical basis for this stretching of the ulnar nerve is
that it passes posterior to the medial epicondyle before
entering the forearm.

Dislocation of the Elbow Joint
• Posterior dislocation of the elbow joint may occur
when children fall on their hands with their elbows
flexed. Dislocations of the elbow may result from
hyperextension or a blow that drives the ulna
posterior or posterolateral. The distal end of the
humerus is driven through the weak anterior part of
the fibrous layer of the joint capsule as the radius and
ulna dislocate posteriorly. The ulnar collateral ligament
is often torn, and an associated fracture of the head of
the radius, coronoid process, or olecranon process of
the ulna may occur. Injury to the ulnar nerve may
occur, resulting in numbness of the little finger and
weakness of flexion and adduction of the wrist.

Wrist Fractures
• Fracture of the distal end of the radius (Colles fracture), the most
common fracture in people >50 years of age, is discussed in the
clinical correlation Fractures of the Radius and Ulna, earlier in this
chapter. Fracture of the scaphoid, relatively common in young
adults, is discussed in the clinical correlation
• Anterior dislocation of the lunate is an uncommon but serious
injury that usually results from a fall on the dorsiflexed wrist. The
lunate is pushed out of its place in the floor of the carpal tunnel
toward the palmar surface of the wrist. The displaced lunate may
compress the median nerve and lead to carpal tunnel syndrome
(discussed earlier in this chapter). Because of its poor blood
supply, avascular necrosis of the lunate may occur. In some cases,
excision of the lunate may be required. In degenerative joint
disease of the wrist, surgical fusion of carpals (arthrodesis) may be
necessary to relieve the severe pain.

Subluxation and Dislocation of Radial Head
• Preschool children, particularly girls, are vulnerable to transient
subluxation (incomplete temporary dislocation) of the head of the
radius (also called nursemaid's elbow and â€œpulled elbow). The
history of these cases is typical. The child is suddenly lifted (jerked)
by the upper limb while the forearm is pronated (e.g., lifting a
child into a bus) . The child may cry out, refuse to use the limb,
protects the limb by holding it with the elbow flexed and the
forearm pronated. The sudden pulling of the upper limb tears the
distal attachment of the anular ligament, where it is loosely
attached to the neck of the radius. The radial head then moves
distally, partially out of the anular ligament. The proximal part of
the torn ligament may become trapped between the head of the
radius and the capitulum of the humerus. The source of pain is the
pinched anular ligament. Treatment of the subluxation consists of
supination of the child's forearm while the elbow is flexed. The
tear in the anular ligament soon heals when the limb is placed in a
sling for 2 weeks.

Colles’ fracture
Colles’ fracture is a fracture of the distal end of the radius
resulting from a fall on the outstretched hand. It commonly
occurs in patients older than 50 years. The force drives the distal
fragment posteriorly and superiorly, and the distal articular
surface is inclined posteriorly . This posterior displacement
produces a posterior bump, sometimes referred to as the
“dinner-fork deformity” because the forearm and wrist
resemble the shape of that eating utensil. Failure to restore the
distal articular surface to its normal position will severely limit
the range of flexion of the wrist joint.

Smith’s fracture
Smith’s fracture is a fracture of the
distal end of the radius and occurs from
a fall on the back of the hand. It is a
reversed Colles’ fracture because the
distal fragment is displaced anteriorly.

Olecranon Bursitis
A small subcutaneous bursa is present over the
olecranon process of the ulna, and repeated
trauma often produces chronic bursitis.

Bull Rider's Thumb
• Bull rider's thumb refers to a sprain
of the radial collateral ligament and
an avulsion fracture of the lateral
part of the proximal phalanx of the
thumb. This injury is common in
individuals who ride mechanical
bulls.

Skier's Thumb
• Skier's thumb (historically, game-keeper's
thumb) refers to the rupture or chronic laxity
of the collateral ligament of the 1st MP joint.
The injury results from hyperabduction of the
MP joint of the thumb, which occurs when the
thumb is held by the ski pole while the rest of
the hand hits the ground or enters the snow.
In severe injuries, the head of the metacarpal
has an avulsion fracture

Synovial Cyst of the Wrist
• Sometimes a non-tender cystic swelling appears on the hand, most
commonly on the dorsum of the wrist. Usually the cyst is the size of a
small grape, but it varies and may be as large as a plum. The thin-walled
cyst contains clear mucinous fluid. The cause of the cyst is unknown, but
it may result from mucoid degeneration. Flexion of the wrist makes the
cyst enlarge, and it may be painful. Clinically, this type of swelling is
called a ganglion(G. swelling or knot). Anatomically, a ganglion refers to
a collection of nerve cells (e.g., a spinal ganglion). These synovial cysts
are close to and often communicate with the synovial sheaths on the
dorsum of the wrist. The distal attachment of the ECRB tendon to the
base of the 3rd metacarpal is another common site for such a cyst. A
cystic swelling of the common flexor synovial sheath on the anterior
aspect of the wrist can enlarge enough to produce compression of the
median nerve by narrowing the carpal tunnel (carpal tunnel syndrome).
This syndrome produces pain and paresthesia in the sensory distribution
of the median nerve and clumsiness of finger movements

Fracture of the Scaphoid
• The scaphoid is the most frequently fractured carpal bone. It
often results from a fall on the palm when the hand is
abducted, the fracture occurring across the narrow part
(waist•) of the scaphoid. Pain occurs primarily on the lateral
side of the wrist, especially during dorsiflexion and abduction
of the hand. Initial radiographs of the wrist may not reveal a
fracture; often this injury is (mis-)diagnosed as a severely
sprained wrist. Radiographs taken 10-14 days later reveal a
fracture because bone resorption has occurred there. Owing
to the poor blood supply to the proximal part of the scaphoid,
union of the fractured parts may take at least 3 months.
Avascular necrosis of the proximal fragment of the scaphoid
(pathological death of bone resulting from inadequate blood
supply) may occur and produce degenerative joint disease of
the wrist. In some cases, it is necessary to fuse the carpals
surgically (arthrodesis).

Mallet or Baseball Finger
• Sudden severe tension on a long extensor tendon
may avulse part of its attachment to the phalanx.
The most common result of the injury is a mallet or
baseball finger. This deformity results from the
distal interphalangeal joint suddenly being forced
into extreme flexion (hyperflexion when, for
example, a baseball is miscaught or a finger is
jammed into the base pad. These actions avulse the
attachment of the tendon to the base of the distal
phalanx. As a result, the person cannot extend the
distal interphalangeal joint. The resultant deformity
bears some resemblance to a mallet.

Fracture of the scaphoid bone
Fracture of the scaphoid bone is common in young adults; unless
treated effectively, the fragments will not unite, and permanent
weakness and pain of the wrist will result, with the subsequent
development of osteoarthritis. The fracture line usually goes
through the narrowest part of the bone, which, because of its
location, is bathed in synovial fluid. The blood vessels to the scaphoid
enter its proximal and distal ends, although the blood supply is
occasionally confined to its distal end. If the latter occurs, a fracture
deprives the proximal fragment of its arterial supply, and this
fragment undergoes avascular necrosis.
Deep tenderness in the anatomic snuffbox after a fall on the
outstretched hand in a young adult makes one suspicious of a
fractured scaphoid.

Fracture of the Hamate
• Fracture of the hamate may result in non-
union of the fractured bony parts because of
the traction produced by the attached
muscles. Because the ulnar nerve is close to
the hook of the hamate, the nerve may be
injured by this fracture, causing decreased
grip strength of the hand. The ulnar artery
may also be damaged when the hamate is
fractured.

Dislocation of the lunate bone
Dislocation of the lunate bone
occasionally occurs in young adults
who fall on the outstretched hand in a
way that causes hyperextension of the
wrist joint. Involvement of the median
nerve is common.

Fractures of the metacarpal bones
Fractures of the metacarpal bones can occur as a
result of direct violence, such as the clenched fist
striking a hard object.
The fracture always angulates dorsally. The “boxer’s
fracture” commonly produces an oblique fracture of
the neck of the fifth and sometimes the fourth
metacarpal bones. The distal fragment is commonly
displaced proximally, thus shortening the finger
posteriorly.

Fracture of the Metacarpals
• The metacarpals (except the 1st) are closely bound
together; hence isolated fractures tend to be stable.
Furthermore, these bones have a good blood
supply, and fractures usually heal rapidly. Severe
crushing injuries of the hand may produce multiple
metacarpal fractures, resulting in instability of the
hand. Fracture of the 5th metacarpal, often referred
to as a boxer's fracture, occurs when an unskilled
person punches someone with a closed fist. The
head of the bone rotates over the distal end of the
shaft, producing a flexion deformity.

Bennett’s fracture
Bennett’s fracture is a fracture of the base of
the metacarpal of the thumb causd when
violence is applied along the long axis of the
thumb or the thumb is forcefully abducted. The
fracture is oblique and enters the
carpometacarpal joint of the thumb, causing
joint instability. Fractures of the phalanges are
common and usually follow direct injury.

Fracture of the Phalanges
• Crushing injuries of the distal phalanges are common
(e.g., when a finger is caught in a car door). Because of
the highly developed sensation in the fingers, these
injuries are extremely painful. A fracture of a distal
phalanx is usually comminuted, and a painful
hematoma (local collection of blood) soon develops.
Fractures of the proximal and middle phalanges are
usually the result of crushing or hyperextension
injuries. Because of the close relationship of phalangeal
fractures to the flexor tendons, the bone fragments
must be carefully realigned to restore normal function
of the fingers.

Compartment Syndrome of the
Forearm
The forearm is enclosed in a sheath of deep fascia, which is attached to the periosteum of the posterior subcutaneous
border of the ulna . This fascial sheath, together with the interosseous membrane and fibrous intermuscular septa, divides
the forearm into several compartments, each having its own muscles, nerves, and blood supply. There is very little room
within each compartment, and any edema can cause secondary vascular compression of the blood vessels; the veins are
first affected, and later the arteries. Soft tissue injury is a common cause, and early diagnosis is critical. Early signs include
altered skin sensation (caused by ischemia of the sensory nerves passing through the compartment),
pain disproportionate to any injury (caused by pressure on nerves within the compartment), pain on passive stretching of
muscles that pass through the compartment (caused by muscle ischemia), tenderness of the skin over the compartment (a
late sign caused by edema), and absence of capillary refill in the nail beds (caused by pressure on the arteries within the
compartment). Once the diagnosis is made, the deep fascia must be incised surgically Interosseous Membrane The
interosseous membrane is a strong membrane that unites the shafts of the radius and the ulna; it is attached to their
interosseous borders . Its fibers run obliquely downward and medially so that a force applied to the lower end of the radius
(e.g., falling on the outstretched hand) is transmitted from the radius to the ulna and from there to the humerus and
scapula.
Its fibers are taut when the forearm is in the midprone position—that is, the position of function. The interosseous
membrane provides attachment for neighboring muscles.
Flexor and Extensor Retinacula The flexor and extensor retinacula are strong bands of deep fascia that hold the long flexor
and extensor tendons in position at the wrist. Flexor Retinaculum The flexor retinaculum is a thickening of deep fascia that
holds the long flexor tendons in position at the wrist. It stretches across the front of the wrist and converts the concave
anterior surface of the hand into an osteofascial tunnel, the carpal tunnel, for the passage of the median nerve and the
flexor tendons of the thumb and fingers . to decompress the affected compartment. A delay of as little as 4 hours can cause
irreversible damage to the muscles.

Patterns of cutaneous innervation
occur in the upper limb
• (1) Segmental innervation (dermatomes) by spinal nerves
• (2) Innervation by multisegmental peripheral (named) nerves.
• The former pattern is easiest to visualize if the limb is placed
in its initial embryonic position (abducted with the thumb
directed superiorly). The segments then progress in
descending order around the limb (starting with C4
dermatome at the root of the neck, proceeding laterally or
distally along the superior surface and then medially or
proximally along the inferior surface, as the T2 dermatome
continues onto the thoracic wall). Like the brachial plexus,
which forms posterior, lateral, and medial (but no anterior)
cords, the arm and forearm have posterior, lateral, and medial
(but no anterior) cutaneous nerves.

Volkmann’s Ischemic Contracture
Volkmann’s ischemic contracture is a contracture of the muscles of the forearm that commonly
follows fractures of the distal end of the humerus or fractures of the radius and ulna. In this
syndrome, a localized segment of the brachial artery goes into spasm, reducing the arterial flow
to the flexor and the extensor
muscles so that they undergo ischemic necrosis. The flexor muscles are larger than the extensor
muscles, and they are therefore the ones mainly affected. The muscles are replaced by fibrous
tissue, which contracts, producing the deformity. The arterial spasm is usually caused by an
overtight cast, but in some
cases the fracture itself may be responsible. The deformity can be explained only by
understanding the anatomy of the region.
Three types of deformity exist:
■■ The long flexor muscles of the carpus and fingers are more contracted than the extensor
muscles, and the wrist joint is flexed; the fingers are extended. If the wrist joint is extended
passively, the fingers become flexed.
■■ The long extensor muscles to the fingers, which are inserted into the extensor expansion
that is attached to the proximal phalanx, are greatly contracted; the metacarpophalangeal joints
and the wrist joint are extended, and the interphalangeal joints of the fingers are flexed.
■■ Both the flexor and extensor muscles of the forearm are contracted. The wrist joint is flexed,
the metacarpophalangeal joints are extended, and the interphalangeal joints are flexed.

Absent Palmaris Longus
The palmaris longus muscle may be absent
on one or both sides of the forearm in
about 10% of persons. Others show
variation in form, such as centrally or
distally placed muscle belly in the place of
a proximal one. Because the muscle is
relatively weak, its absence produces no
disability.

Stenosing Synovitis of the Abductor Pollicis
Longus and Extensor Pollicis Brevis Tendons
As a result of repeated friction between these
tendons and the styloid process of the radius,
they sometimes become edematous and swell.
Later, fibrosis of the synovial sheath produces
a condition known as stenosing tenosynovitis in
which movement of the tendons becomes
restricted. Advanced cases require surgical
incision along the constricting sheath.

Rupture of the Extensor Pollicis Longus
Tendon
Rupture of this tendon can occur after
fracture of the distal third of the radius.
Roughening of the dorsal tubercle of the
radius by the fracture line can cause
excessive friction on the tendon, which can
then rupture. Rheumatoid arthritis can also
cause rupture of this tendon.

Anatomic Snuffbox”
The anatomic snuffbox is a term commonly used to
describe a triangular skin depression on the lateral
side of the wrist that is bounded medially by the
tendon of the extensor pollicis longus and laterally by
the tendons of the abductor pollicis longus and
extensor pollicis brevis. Its clinical importance lies in
the fact that the scaphoid bone is most easily alpated
here and that the pulsations of the radial artery can
be felt here.

Tennis Elbow
Tennis elbow is caused by a partial tearing or
degeneration of the origin of the superficial extensor
muscles from the lateral epicondyle of the humerus.
It is characterized by pain and tenderness
over the lateral epicondyle of the humerus, with
pain radiating down the lateral side of the forearm;
it is common in tennis players, violinists, and
housewives.

Dupuytren’s Contracture
Dupuytren’s contracture is a localized thickening and contracture of the
palmar aponeurosis, which limits hand function and may eventually
disable the hand. It commonly starts near the root of the ring finger and
draws that finger into the
palm, flexing it at the metacarpophalangeal joint. Later, the condition
involves the little finger in the same manner. In long-standing cases, the
pull on the fibrous sheaths of thesefingers results in flexion of the
proximal interphalangeal
joints. The distal interphalangeal joints are not involved and are actually
extended by the pressure of the fingers against the palm.
Surgical division of the fibrous bands followed by physiotherapy to the
hand is the usual form of treatment. The alternative treatment of
injection of the enzyme collagenase into the contracted bands of fibrous
tissue has been shown to significantly reduce the contractures and
improve mobility.

Dupuytren Contracture of Palmar Fascia
• Dupuytren contracture is a disease of the palmar fascia resulting in
progressive shortening, thickening, and fibrosis of the palmar
fascia and aponeurosis. The fibrous degeneration of the
longitudinal bands of the palmar aponeurosis on the medial side
of the hand pulls the 4th and 5th fingers into partial flexion at the
metacarpophalangeal and proximal interphalangeal joints. The
contracture is frequently bilateral and is seen in some men >50
years of age. Its cause is unknown, but evidence points to a
hereditary predisposition. The disease first manifests as painless
nodular thickenings of the palmar aponeurosis that adhere to the
skin. Gradually, progressive contracture of the longitudinal bands
produces raised ridges in the palmar skin that extend from the
proximal part of the hand to the base of the 4th and 5th fingers.
Treatment of Dupuytren contracture usually involves surgical
excision of all fibrotic parts of the palmar fascia to free the fingers

Cilinical anatomy upper limb

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Cilinical anatomy upper limb