2. Objectives
• External structure of the spinal cord.
• Internal structure of the spinal cord.
• Blood supply
• Spinal cord lesions and symptoms
3. Spinal cord
• Spinal cord is cylindrical structure that is
continuous with caudal brain stem and
extends through vertebral column until its
termination( Conus medullaris) at L1-L2.
4. Gross Appearance
• Foramen magnum L1/L2 (adult)
• L3 (newborn)
• Occupies upper ⅔ of vertebral canal
• Surrounded by 3 layers of meninges:
– Dura mater
– Arachnoid mater
– Pia mater
• CSF in subarachnoid space
5. Dura mater
• Dense, strong fibrous membrane
• Encloses the spinal cord & cauda equina
• Ends at the level of S2
• Separated from wall of vertebral canal by
the extradural space
• Contains loose areolar tissue & internal
vertebral venous space
6. Arachnoid mater
• Delicate impermeable membrane
• Lies between pia and dura mater
• Separated from pia mater by
subarachnoid space
• Ends on filum terminale at level of S2
7. Pia mater
• Vascular membrane
• Closely covers spinal cord
• Thickened on either side between nerve
roots to form the ligamentum denticulatum
• Ends as filum terminale
16. Gray matter
• H-shaped pillar with anterior & posterior gray
horns
• United by gray commissure containing the
central canal
• Amount of gray matter ~ the amount of
muscle innervated
• Consists of nerve cells, neuroglia, blood
vessels
18. • Nerve cells in the posterior gray columns
• 4 nerve cell groups
• Substantia gelatinosa
– Situated at the apex
– Throughout the length of spinal cord
– Receives afferent fibres concerning with pain,
temperature & touch from posterior root.
19. • Nucleus proprius
– anterior to substantia gelatinosa
– present throughout the whole length of spinal
cord
– main bulk of cells in posterior gray column
– receives fibers from posterior white column
that are assoc with proprioception, 2-point
discrimination & vibration
20. • Nucleus dorsalis (Clark’s column)
– base of posterior column
– C8 – L3 / L4
– associated with proprioceptive endings
(neuromuscular spindles & tendon spindles)
• Visceral afferent nucleus
– lateral to nucleus dorsalis
– T1 – L3
– receives visceral afferent info
21.
22.
23.
24. White Matter
• Divided into
– Anterior white column
– Lateral white column
– Posterior white column
• Consists of nerve fibres, neuroglia, blood
vessels
• White due to myelinated fibres
31. CST
• Cerebral motor cortex (area 4; precentral gyrus) ->very
long axons->Decussate in lower medulla.
• Enter the LATERAL FUNICULUS where they travel
medial to the DSCT.
• 2 neurons. The first one is an upper motor neuron and
lies in the cerebral cortex. The second one lies in the
contralateral ventral horn and is a
lower motor neuron.
42. Dorsal spinocerebellar tract
• Clarke column- C8-T3
• Muscle joint sense pathways to cerebellum
• Unconscious proprioception
• Muscle joint info from muscle spindles, GTO,
joint receptors of the trunk & lower limbs
• Info is used by the cerebellum in the
coordination of movements & maintenance of
posture
• Lesion- Incoordination & Ataxia
43. Blood supply
Arteries of the spinal cord
• Anterior spinal artery
• Posterior spinal artery
• Segmental spinal arteries
44.
45.
46. Anterior spinal artery
• Formed by the union of 2 arteries
• From vertebral artery
• Supply anterior ⅔ of spinal cord
Posterior spinal arteries
• Arise from vertebral artery or posterior
inferior cerebellar arteries (PICA)
• Descend close to the posterior roots
• Supply posterior ⅓ of spinal cord
47.
48.
49.
50.
51. Segmental spinal arteries
• Branches of arteries outside the vertebral
column
• Gives off the anterior & posterior radicular
arteries
• Great anterior medullary artery of
Adamkiewicz
• Arise from lateral intercostal artery or
lumbar artery at any level from T8 – L3
