26 External features of the spinal cord

Question 1

31 pairs of spinal nerve?

Answer 1

Cervical: 8
Thoracic: 12
Lumbar: 5
Sacral: 5
Coccygeal:1

Question 2

What is white communicating ramus? (from where to where)

Answer 2

Myelination of preganglionic sympathetic fibers, carrying them from the spinal cord to sympathetic ganglia

Question 3

What is gray communicating ramus? (from where to where)

Answer 3

Lese myelinated, carry post-ganglionic sympathetic fibers from sympathetic ganglia to spinal nerves

Question 4

Describe the organisation of the matching between spinal nerves and their corresponding vertebral level.

Answer 4

1. From C1-C7: spinal nerves exit above their corresponding vertebral
2. C8: nerve exits below C7 vertebrae (between C7 and T1 vertebrae)
3. from T1 onwards: exit below their corresponding vertebrae

Question 5

Which of the following is true?
A. Vertebral canal and spinal cord grow at the same rate until 3 months old fetal age

B. After 3 months, the vertebrae grows slower than the spinal cord

C. Caudal tip of the conus medullaris is at the level between L1-L2 vertebrae

D. From cervical to sacral levels, the dorsal and central roots are stretched progressively longer, with longer distances to travel and reach exits

Answer 5

All except B

Should be vertebrae grows faster than the spinal cord

Question 6

What is lumbar cistern?

Answer 6

Enlarged subarachnoid space from end of spinal cord (L1-L2) to the end of the dural sheath (S2 vertebrae)

Question 7

What is caudal equina?

Answer 7

Collection of dorsal and ventral roots in the lumbar cistern that reside in subarachnoid space

Question 8

Which level for lumbar puncture?

Answer 8

L4, Iliac crest as landmark

Question 9

Lateral protrusion of disc level L4-5 affects which spinal nerve?

Answer 9

L5 spinal nerve (because L4 spinal nerve exits above already);

Protrusion at disc level L5-S1 affects S1 spinal nerve, not L5!

Question 10

Posteromedial protrusion of level L4-5?

Answer 10

Affects L4 spinal nerve but may also affect L5 and sometimes S1-4 spinal nerves.

Question 11

White matter increases from where to where?

Answer 11

Up the spinal cord

Question 12

Gray matter variations in spinal cord?

Answer 12

Cervical and lumbar enlargements due to suppliy to the limbs

Question 13

Lateral horn contains?

Answer 13

Preganglionic sympathetic nervous system

Question 14

Rexed laminae:

Lamina 3 &4 =?

Answer 14

Proper sensory nucleus for sensory processing, contributes to the spinothalamic tract

Question 15

Laminae 1,4,5?

Answer 15

Contralateral spinothalamic tract

Question 16

Lamina 7?

Answer 16

1. intermediolateral cell column (T1-L2/3) - preganglionic sympathetic neurons;
2. Clarke’s nucleus (C8-L2): origin of the DSCT;
3. Sacral parasympathetic nucleus

(= lateral horns + Clarke’s)

Question 17

Lamina 9?

Answer 17

Motor neurons