3. Long :-
Men=45cm(18inch)
Women=43cm(17inch)
Width :-
Cervical and lumbar = 1/2inch thick
Thoracic area = 1/4inch thick
Begins from occipital bone until L1&L2
the end of spinal cord = filum terminal
4.
5.
6.
7. Meninges
Epidural = External of dura(fat-fil)
Subdural space = Serous fluid
Subarachnoid = Between pia and arachnoid (CSF filled)
Dura mater (dural
sheath)=outermost
Arachnoid’s mater =
thin,movable
Pia mater=forms filum
terminal,denticulate
ligament
Connective
tissue
membranes
Subdural
space
Subarachnoid
Epidural
8.
9. Spinal segment = spinal nerve
Spinal nerve has two roots
Dorsal root ganglion = swelling like structure
Anterior root= ventral root
Posterior root=dorsal root
SPINAL NERVE
10.
11.
12. Spinal cord have 31 segment
8 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Coccygeal
The spinal segments that contribute to the nerve
of the upper are enlargement to the form cervical
and lumbar enlargements
13. vertebrae spinal segments
C1 to C4 (upper cervical) same
C4 To C7 (lower cervical) +1
T1 to T7 +2
T7 to T9 +3
T10 L1,L2
T11 L3,L4
T12 L5,S1
L1 sacral and coccygeal nerve
21. Tract is a bundle of nerve fibers (within CNS)
having the same :-
Origin
Course
Destination
Function
22.
23. The name of the tract = origin
= destination
The axons within each tract are grouped according
to the body region innervated
Long tracts at white matter
Short tracts at gray matter
There are 2 types of tract :-
Ascending tract
=Sensory
Descending tract
=Motor
24.
25. Decussation is the cross-over of the tract
from one side to the other.
Therefore,there are instances where the left
side of the body is controlled by the right
brain hemisphere.
Decussation occurs at different locations for
each tracts.
31. Contain a sequence of 3 neurons
from the receptor to the cerebral
cortex
1st order neuron:
Sensory neuron that delivers
information from the receptor to the
CNS.
2nd order:
Has cell body in the spinal cord or
medulla oblongata
Axon decussate
3rd order neuron:
Has cell body in thalamus
Axon terminates on cerebral
cortex ipsilaterally
1
2
3
32. Modality: Discriminative Touch
Sensation Conscious
Proprioception
Receptor: Most receptors except
free nerve endings
Ist Neuron: Dorsal Root Ganglion
(Spinal Ganglion)
Dorsal Column Nuclei (Nucleus
Gracilis
Thalamus (VPLc) ,Corona Radiata
Termination: Primary Somesthetic
Area (S I)
Posterior White Column-Medial
Lemniscal Pathway
33. Modality:pain and thermal
sensations.
Ist Neuron : dorsal horn
2nd Neuron: mostly in the
nucleus proprius), decussate
within one segment by passing
through the ventral white
commissure
3rd Neuron: ventral posterior
nucleus of the thalamus
Thalamic neurons project to the
somatosensory cortex
34. Modality:non- discriminative
touch and pressure
Ist Neuron : dorsal horn
2nd Neuron: nucleus
proprius,crossing to opposite
side by passing through the
ventral white commissure
3rd Neuron: in ventral
posterior nucleus of the
thalamus
Thalamic neurons project to the
somatosensory cortex
35. Ist Neuron neuron lie in base of
the dorsal horn of the lumbosacral
segments
cross to opposite side, ascend as
far as the midbrain
2nd Neuron: terminating in the
cerebellar cortex
Both spinocerebellar tracts convey
sensory information to the same
side of the cerebellum
36. Info:Present only above
level L3
Ist Neuron in Clark’s
column
2nd Neuron: terminate
ipsilaterally in the
cerebellar cortex
37.
38. 2 Sequence of neuron(from cerebral
cortex/brain stem – muscle)
Upper Motor Neuron(UMN)
o Spinal cord -> brain
o Cell body cross over before terminate on lower
motor neuron
Lower Motor Neuron(LMN)
o Spinal cord -> muscle
o Cell body pass through posterior root of spinal
nerve
41. Function:voluntary movement
: fine skill movement
Anterior corticospinal tract
o Origin:motor cortex (4,6)
:somatosensory cortex (1,2,3)
o Course:pass through midbrain(cerebral peduncle)
pyramid of medulla oblongata
o Termination: anterior white column
42. Lateral corticospinal tract
o Origin: motor cortex (4,6)
:somatosensory cortex (1,2,3)
o Course: pass through midbrain(cerebral peduncle)
(cross over)
pyramid of medulla oblongata
o Termination: lateral white column
o Corticobulbar innervate cranial nerves
motor nuclei of CNS
43.
44.
45.
46.
47. Function: coordination of voluntary and reflex
movement
: control of muscle tone
: control of respiration and diameter of
blood vessel
Origin: Reticular formation (pontine & medulla)
Course :pass through medial pontine
lateral medulla
Termination: ventral funniculus
48.
49. Function: coordination of head and neck to
the visual & audio stimuli
Origin : superior colliculus
Course : pass through periaquductal
(cross)
Dorsal tegmental
Termination: Anterior median fissure
(cervical area)
50.
51. Function : controls flexor
muscle tone
Origin : Red nucleus
Course :cross to
(lower cervical segment)
Termination: lateral
white column
52. Lateral vestibulospinal tract
Function: control extensor
muscle tone
: antigravity
maintenance
of posture
Origin : lateral vestibular
(Derter’s) nucleus
Termination :ventral
funniculus
53. • Medial vestibulospinal tract
Function: control
movement
of head
:maintain
equilibrium
Origin:medial vestibular
nucleus
Termination: ventral
funniculus
+
medial
funniculus