Spinal cord function and dysfunction

Question 1

Recall the segments of the spinal cord

Answer 1

31 total
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 2

How do nerves exit the spinal cord?

Answer 2

Through intervertebral foramina

Question 3

Recall the relationship between each spinal nerve and its point of exit from the spinal cord

Answer 3

C1-C7 emerge above their corresponding vertebrae
C8 comes out below C7
T1 onwards emerge below their corresponding vertebra

Question 4

What is the white matter of the spinal cord made up of?

Answer 4

Ascending and descending tracts

Question 5

Within the nervous system, what words replace the anatomical descriptions of “superior” and “inferior”?

Answer 5

Superior = rostral
Inferior = caudal

Question 6

What is the grey matter of the spinal cord involved in?

Answer 6

Discriminative touch and proprioception

Question 7

What are the main sensory and motor tracts of the spinal cord?

Answer 7

Sensory - spinothalamic

Motor - corticospinal

Question 8

Explain the structure and positioning of each sensory “system” in the spinal cord

Answer 8

3 neurons (primary, secondary, tertiary)
Where 1st order synapses with 2nd order = crossing to other side of spinal cord

Question 9

Which tract carries information about pain and temperature?

Answer 9

Somatosensory

Question 10

What is the consequence of a disruption in brain influence over reflex action?

Answer 10

Spasticity due to lack of higher control

Question 11

What feature is unique to the thoracic segments of the spinal cord?

Answer 11

Intermediate lateral horn

Question 12

Describe the distribution of sensory and motor fibres in the spinal cord?

Answer 12

Motor = ventral
Sensory = dorsal
Both = lateral

Question 13

Name the dorsal and ventral fissures in each spinal segment and recall which is wider

Answer 13

Dorsal = posterior median sulcus
Ventral = anterior median fissure (wider)

Question 14

At which vertebral level does the spinal cord end?

Answer 14

L2

Question 15

Recall the regions of enlarged spinal cord

Answer 15

For upper limbs: C3–> T1

For lower limbs: L1–> S3

Question 16

Describe the relative pathways of sensory and motor neurons through the intervertebral foramina

Answer 16

Sensory = enter anteriorly
Motor = exit posteriorly

Question 17

Where are the motor neuronal cell bodies located?

Answer 17

Grey matter

Question 18

Where are herniated discs most likely to occur, and why?

Answer 18

L5/S1

Discs are present posteriorly but not anteriorly

Question 19

Which 2 layers of the meninges extend past the end of the spinal cord?

Answer 19

Dura and arachoid

Question 20

What part of the spinal cord is most amenable to CSF removal and why?

Answer 20

Between L2 and S2 as there is a large volume of CSF and some floating neurons but no spinal cord

Question 21

Recall the 3 factors affecting the severity of a spinal cord lesion

Answer 21

1. Amount of tissue lost
2. Vertical level
3. Transverse plane

Question 22

Recall the expected pathology following a spinal cord injury

Answer 22

1. Spinal shock - flaccid paralysis and absence of reflexes

2. Return of reflexes leading to hyperreflexia and spasticity

Question 23

Damage to what element of the CNS would stop someone being able to sense pain?

Answer 23

Dorsal columns