Neuroanatomy: Spinal Cord Anatomy and Ascending + Descending Pathways

Question 1

Which are the two areas of enlargement in the spinal cord?

Answer 1

Cervical (upper limb) and lumbar (lower limb).

Question 2

What are the named segments of the nerve fibres as they leave the spinal cord?

Answer 2

Dorsal/ventral rootlets
Posterior/anterior roots
Mixed spinal nerve
Posterior/anterior rami

Question 3

Which rami carries motor information?

Answer 3

Anterior (move forward)

Question 4

Which rami carries sensory information?

Answer 4

Posterior (kiss my arse)

Question 5

Why is the posterior root larger than the anterior root?

Answer 5

Enlarged by dorsal root ganglion.

Question 6

What is the name and level of the termination of the spinal cord?

Answer 6

Conus Medullaris (L1)

Question 7

What structure continues down the cord, anchoring to the dorsum of the coccyx?

Answer 7

Filum terminale

Question 8

What name is given to the spinal levels below the termination at L1?

Answer 8

Cauda Equina

Question 9

Which structure suspends the spinal cord in the canal?

Answer 9

Denticulate ligament

Question 10

What layers of meninges form the tentacular ligament?

Answer 10

Pial and Arachnoid tissue (attaching it to the dura)

Question 11

In the grey matter of the spinal cord, which horns are the biggest?

Answer 11

Posterior - extend right to edge.

Question 12

Which horn can also be found between spinal segments T1 to L2?

Answer 12

Lateral horn (pre-ganglionic sympathetic neurones)

Question 13

What is the blood supply to the spinal cord?

Answer 13

Longitudinal arteries: 1 anterior, 2 posterior. originating at vertebral arteries.

Segmental arteries: derived from vertebral, intercostal and lumbar arteries.

Radicular arteries: travel along the dorsal and ventral routes.

Question 14

In the spine, unlike in the cranial cavity, there is space between dura and bone - what is this space called?

Answer 14

Epidural Space

Question 15

What is found in the epidural space?

Answer 15

Adipose tissue, anterior and posterior venous plexi.

Question 16

Where is the somatosensory cortex located?

Answer 16

Post-central gyrus.

Question 17

Somatosensory information from which area DOES NOT travel within the spinal cord?

Answer 17

Face and scalp

Question 18

In which tract does fine touch and proprioception travel?

Answer 18

Posterior (Dorsal) Column Medial Lemniscal Pathway

Question 19

What are the 2 components of the dorsal column?

Answer 19

Fasciculus Gracilis & Fasciculus Cuneatus

Question 20

What does the fasciculus gracilis (medial) carry?

Answer 20

Sensation from the legs

Question 21

What dies the fasciculus cuneatus (lateral) carry?

Answer 21

Sensation from the arms

Question 22

What is the course of the PCML pathway?

Answer 22

Cervical and lumbar cords decussate in medulla
2nd order neurones to the thalamus
3rd order neurones to somatosensory cortex

Question 23

What information is carried in the Spinothalamic tract?

Answer 23

Pain, temperature & deep pressure

Question 24

What is the course of the spinothalamic tract?

Answer 24

Tracts decussate at whatever level they enter
2nd order neurones towards thalamus.
3rd order neurones from thalamus to somatosensory cortex.

Question 25

Where is the motor cortex located?

Answer 25

The pre-central gyrus

Question 26

What motor tract carries information about fine, precise movement?

Answer 26

Corticospinal Tract

Question 27

What is the course of the corticospinal tract?

Answer 27

Begins in the cortex and descends to midbrain.
85% fibres cross at the medulla forming the lateral corticospinal tract.
15% continue down forming the ventral corticospinal tract.
The 15% decussate at the appropriate level in the spinal cord.

Question 28

What may the corticospinal tract also be referred to as?

Answer 28

Pyramidal tract

Question 29

Which tract is responsible for orientating head and eye movement to audio and visual stimuli?

Answer 29

Tectospinal tract

Question 30

Which tract forms a diffuse network of nuclei and interconnections, responsible for many motor functions e.g. voluntary movement, respiration?

Answer 30

Reticulospinal tract

Question 31

Which tract is responsible for excitatory input to antigravity (extensor) muscles?

Answer 31

Vestibulospinal tract

Question 32

What is unusual about the vestibulospinal tract?

Answer 32

It is ipsilateral and does not cross the tract.