The female pelvis is ideal for childbearing. Complete knowledge on it helps a obstetrician or midwife to conduct normal labour as well as detect any abnormalities related to abnormal pelvis.

1. PREPARED BY:
SRUJANI SWETASINA DASH
NURSING TUTOR
G.N.M.INSTITUTE
A.N.M.M.C.H, GAYA

2.  NEED FOR STUDY ABOUT PELVIS IN OBSTETRIC
 FUNCTIONS OF PELVIS
 TYPES OF PELVIS
 STRUCTURE OF FEMALE PELVIS
 JOINTS
 ANATOMICAL DIVISION
 BONY LANDMARKS
 DIAMETERS OF TRUE PELVIS
 SUMMARY
 BIBLIOGRAPHY

3.  INTRODUCTION:
Obstetric is branch of medical science which deals with
the pregnancy, childbirth and postpartum period. The
female pelvis act as birth canal during childbirth and it
also provides space for growth and development of fetus.
Therefore it is necessary to know the structure of normal
female pelvis for conducting deliveries.

4.  Allow movement of the body especially walking and
running.
 Permits person to sit and kneel.
 Female pelvis is adapted for childbearing.
 Transmits the weight of trunk to the legs.
 Takes weight (ischial tuberosity)of the body while in
sitting.
 Protects the pelvic organs.

5. According to the shape of brim of pelvis, it is divided into
four types-
1. Gynaecoid Pelvis (Female pelvis)
2. Android Pelvis (Male Pelvis)
3. Anthropoid Pelvis
4. Platypelloid Pelvis (Abnormal Pelvis)

6. Formed by four bones-
1. Innominate bone (Hip Bone) -2
2. Sacrum -1
3. Coccyx -1

7.  Also known as hip bone or coxal bone.
 It has 3 parts- Ilium, Ischium and Pubis.
 There is a cup shaped depression on the lateral side of
innominate bone called as “acetabulum”. The ilium, ischium and
pubis fused to form the acetabulum. The head of the femur
articulates in this part.
 There is a foramen at the inferior portion known as “obturator
foramen”
ILIUM
 Ilium is the upper flat portion of innominate bone.
 It has a superior border called as “iliac crest”
 The flat surface of ilium is called as “iliac fossa”
 It has four spines-
1.Anterior superior iliac spine- anterior end of iliac crest
2.Anterior inferior iliac spine - below anterior superior spine
3.Posterior superior iliac spine- posterior end of iliac crest
4.Posterior inferior iliac spine- below posterior superior spine

8. ISCHIUM
 It is the posteroinferior part of innominate bone.
 The thick part of ischium is called as “ischial tuberosity”.
 The posterior border of ischium has a spine called as
“ischial spine”.
 There are two curvature above and below the ischial
spine- a. Greater sciatic notch (above)
b. Lesser sciatic notch (below)
PUBIS
 It is the anteroinferior part of innominate bone.
 It has a body, superior ramus and inferior ramus.
 The superior border of the body is known as the pubic
crest.
 The inferior ramus unites to form pubic arch.

10. SACRUM
 Wedge shaped bone with concave anterior surface.
 Composed of five fused rudimentary vertebrae.
 The upper border of the first sacral vertebra protrudes inward
and forms “sacral promontory”.
 The lateral part of sacrum is called as wing or ala.
 Upper part of sacrum is called as base which articulates with L5
and the lower end is apex which articulates with coccyx
 There are five sacral foramen are present in each side.
COCCYX
 Triangular in shape.
 Composed of four fused rudimentary vertebrae.

13. There are four joints-
 Sacroiliac joint (2) - Joint between innominate
bone and sacrum
 Sacrococcygeal joint (1) - Joint between sacrum and
coccyx
 Symphysis Pubis (1) - Cartilaginous joint between
both the pubis
Sacrococcygeal joint

14. Pelvis is anatomically divided into two parts from the level of the
brim -
1. False Pelvis
2. True Pelvis
False Pelvis
 It is the part above the brim of pelvis.
 Formed by iliac portions of innominate bone and is limited above by
the iliac crests.
 It’s function is to support the enlarged uterus during pregnancy. It
has no role as birth canal.
True Pelvis
 It is the part below the brim of pelvis.
 Anteriorly it is shallow, formed by the symphysis pubis and measures
4 cm.
 Posteriorly it is deep, formed by sacrum and coccyx and measures
11.5cm.
 It is divided into Inlet (Brim), Cavity and Outlet for descriptive
purpose.
 It forms the birth canal through which fetus pass during childbirth.

15.  There are certain landmarks on
the brim of pelvis.
 Sequence from anterior to
posterior-
1. Upper border of symphysis pubis
2. Pubic crest
3. Pubic tubercle
4. Pectineal line
5. Ilio pubic eminence
6. Ilio pectineal line
7. Sacroiliac joint
8. Anterior border of ala of sacrum
9. Sacral promontory

16.  True pelvis has inlet (brim), cavity and outlet.
 There are three diameters in each of the part-
a. Anteroposterior
b. Oblique
c. Transverse

17. INLET/BRIM CAVITY OUTLET
ANTERO-
POSTERIOR
Distance between
the midpoint of
sacral promontory
to the upper boder
of symphysis pubis.
Circular in shape
and is not possible
to measure.
Distance between
the lower border
of symphysis pubis
to sacrococcygeal
joint.
11cm 12cm 13cm
OBLIQUE Distance between
sacroiliac joint of
one side to the ilio
pubic eminence of
opposite side.
Circular in shape
and is not possible
to measure.
Distance between
the obturator
foramen to the
sacro spinous
ligaments although
there is no fixed
point.
12cm 12cm 12cm
TRANSVERSE Distance between two
farthest points over
iliopectineal line.
Circular in shape
and is not possible
to measure.
Distance between
two ischial spines.
13cm 12cm 11cm

18.  Female pelvis is significant in obstetrical standpoint
because it provides passage for the fetus to come out
during delivery and is ideal for childbirth.
 A midwife must be competent to recognise a normal pelvis
in order to conduct normal labour and able to detect
deviations from normal.

19.  Dutta D.C, “Textbook Of Obstetrics”, Jaypee
Brothers , The Health Science Publishers, 8th
edition, Pg.98-105
 Jacob Annamma, “A Comprehensive Textbook
of Midwifery”, Jaypee Brothers Medical
Publishers(P)LTD, 2nd edition, Pg.43-51
 Elizabeth Marie, “Midwifery for Nurses”, CBS
Publishers and Distributors Pvt Ltd, 2nd
edition, Pg.90-96