short notes on spinal cord

1. Department of Rachana Sharir
Dr Samadhan M Patil
M.D. Rachana Sharir

2. Today’s Topic
 Spinal cord

3. Introduction
 It is the long cylindrical lower part of CNS
 It is the main pathway for information connecting the brain and PNS
 It is enclosed in the three meninges and occupies upper 2/3 of vertebral
canal
 It gives rise to 31 pairs of spinal nerves
 Thus spinal cord is a major connection between body and brain

4. Features
 Length:
18 inch or 45 cm in an adult male
42 cm in adult female
 Weight: 30 gm
 Extends: From upper border of atlas vertebra to lower border of L1
 Superiorly: continuous with the medulla oblongata
 Inferiorly: terminates as conus medullaris, below the level of conus
medullaris only pia mater is continued as a thin fibrous cord, the filum
terminale

5. Cauda equina
 Dorsal and ventral nerve roots of right and left sides of L2-L5, S1-S5 and
Co1 nerves lie almost vertically around filum terminale. These are called
cauda equina.
 These resemble a horse’s tail
 There are 40 nerve roots at the beginning of cauda equina

6. Enlargement
Spinal cord is not unique in its width. It shows some enlargements as:
1. Cervical enlargement:
 For supply of upper limb muscles
 Extends from C4 to T1 spinal segments
 Maximum diameter: 38 mm (at the level of C6 segment)
2. Lumber enlargement:
 For supply of lower limb muscles
 Extends from L2 to S3 spinal segments
 Maximum diameter: 35 mm ( at the level of S1 segment)

7. External features
 Two fissure
1. Anterior median fissure
2. Posterior median fissure
 Two halves
1. Right half
2. Left half
 Two sulci
1. Anterolateral sulci
2. Postero-lateral sulci
 Three regions on each half
1. Anterior region
2. Lateral region
3. Posterior region

8. Internal features
Cross section of spinal cord shows:
 Three columns of white matter (Outside)
 H shaped gray matter (Inner side)
 Central canal:
 Exactly in middle there is a hollow cavity called as central canal.
 It contains CSF
 Opens above in 4th ventricle

9.  White matter: Subdivided in 3 region
1. Anterior funiculus/ white column:
 It is present between antero-median fissure and the anterior horn
 It chiefly contains motor nerve fibres
2. Lateral funiculus/ white column:
 It is present between anterior and posterior horn of grey matter
3. Posterior funiculus/ white column:
 It is present between postero-median fissure and postero-lateral sulcus
 It contains sensory nerve tracts

10.  Gray matter: Look like H shaped, It shows 2 horns:
1. Anterior horn
 Directed to anterolateral side
 Smaller in length but broader in width
2. Posterior horn
 Directed to postero-lateral side
 Longer and narrower
3. Additional Lateral horn for the supply of viscera at the level of T1-L2 and S2-S4
segments (part of ANS)

11. Clinical anatomy
 Conus medullaris syndrome: Injury to S2, S3, S4 segments of spinal cord
 Cauda equina syndrome: Damage to cauda equina
 Poliomyelitis: It is a viral disease which involves anterior horn cells
 Tabes dorsalis: Degenerative lesions of dorsal nerve roots and of
posterior white columns

12. Reference
 B D Chaurasia’s Human Anatomy (Volume 4) 7th edition

13. Thank you…