Spinal cord function and dysfunction

Question 1

How many pairs of Spinal nerves are there?

Answer 1

31:

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

Question 2

Where do nerves leave the vertebral column?

Answer 2

Intervertebral foramina

Question 3

Where are the enlargements in the cord for limb nerves?

Why?

Answer 3

Cervical (C3-T1) - More motor neurones that go to the muscles of the upper limb

Lumbar (L1-S3) - More motor neurones that go to the muscles of the lower limb

Question 4

Where do the Cervical nerves leave the spinal column?

Answer 4

C1-C7 above the vertebrae

C8 Below C7 vertebrae

(All others below)

Question 5

At what level of the Vertebral column does Co1 originate?

What is this an example of?

Answer 5

Coccygeal

Around L1

Discrepancy between spinal and vertebral levels

Question 6

What is the difference between the location of the Dura in the brain and spinal cord?

What does this allow?

Answer 6

There is no space between dura and cranium

There is a space between dura and spinal column

This allows the injection of anaesthetics into the epidural space

Question 7

Where does the Pia mater end in the vertebral column?

Answer 7

At the end of the spinal cord, leaving only a filament that tethers it to the sacrum.

Question 8

What tethers the spinal cord and holds it in the middle of the subarachnoid space?

Answer 8

Denticulate Ligaments

Question 9

What is a Dermatome?

Answer 9

An area of skin innovated by one pair of spinal nerves

Question 10

What is a myotome?

Answer 10

Muscles innovated by one pair of spinal nerves

Question 11

What type of fibres are contained in the anterior root?

Answer 11

Motor fibres

Question 12

What type of fibres are contained in the posterior roots?

Answer 12

Sensory fibres

Question 13

What is a ramus?

Answer 13

A branch of the spinal nerve that contains both motor and sensory fibres

Question 14

What is a root, and what is it formed from?

Answer 14

A section of the spinal nerve formed of only one type of fibre, formed from rootlets

Question 15

Label the sections of this transverse plane of the Spinal Cord

Answer 15

Question 16

Label the Major Tracts of the White Matter

Answer 16

Question 17

What proportion of motor fibres cross over and innovate limbs?

Answer 17

About 85%

Question 18

How many neurones are involved in Sensory Pathways?

Answer 18

3

Primary sensory neurone enters cord and synapses onto secondary

Secondary crosses over - either in cord or medulla

Secondary synapses with tertiary in the Thalamus

Tertiary travels to cortex

Question 19

What does the Dorsal column pathway carry?

Whats it made of?

Answer 19

Discriminative touch, Vibration and Proprioception sensory infomation

Fasciculus Gracilis and Fasciculus Cuneatus

Question 20

Where does the Dorsal Column Pathway cross over?

Answer 20

Medulla

Question 21

What information does the Spinothalamic tract carry?

Where does it cross over?

Answer 21

Pain and Temperature

In the cord

Question 22

Where in the cord can you find a third Lateral horn?

Answer 22

Thoracolumbar - Sympathetic motor neurones

Sacral - Parasympathetic motor neurones

Question 23

Where in the Cord is there less grey matter?

Answer 23

In the thoracic region as it has less muscles, so fewer motor neurones are needed

Question 24

What are the main differences in the Cord between levels C5 and L5?

Answer 24

• More white matter at C5 as it has to carry more neurones than at lower levels
• C5 is more oval and just bigger

Question 25

Where is the Cuneate fascicularis present?

Answer 25

Only from around T1 and up because it carries information from the arms, whereas the Gracile fascicularis is present at all levels

Question 26

If you have a lesion on the dorsal/posterior aspect of the cord, what is most likely to be affected?

Answer 26

Sensory signals as the Dorsal Column pathway is there, whereas the Corticospinal tracts are more anterior/ventral