Spinal nerves, general principles of nerve supply (dave's notes)

Question 1

How many pairs of spinal nerves are there? What are they?

Answer 1

31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Question 2

Spinal nerves form as roots and end as divisions/peripheral branches. Give the sequence of formation

Answer 2

Roots - anterior (motor + pain)
           - posterior (sensory)
Ganglia - posterior root only; no synapses here just cell bodies)
Rami - anterior and posterior
divisions  - flexion/extension

Question 3

Each spinal nerve is formed by union of an …… root and a ……. root emerging from the side of the ……… ……

Answer 3

Anterior , posterior, spinal cord

Question 4

Where does union of the anterior and posterior roots take pale?

Answer 4

In the intervertebral foramen immediately distal to the swelling of the posterior root

Question 5

What does the anterior root of every spinal nerve contain?

Answer 5

Motor fibres for skeletal muscle

Question 6

What does the posterior root of every spinal nerve contain?

Answer 6

Sensory fibres whose cell bodies are in the posterior root ganglion (no synapses here though)

Question 7

What happens immediately after formation of the spinal nerve?

Answer 7

It divides into an anterior and posterior ramus.

Question 8

What do anterior rami form?

Answer 8

The great plexuses

Question 9

What are peripheral nerve trunks in the limbs supplied by?

Answer 9

Local arteries

Question 10

What is notable about the arterial supply of the sciatic and median nerve? How are other nerves supplied?

Answer 10

They each have their own blood supply. Elsewhere, the regional artery supplies nerves by a series of segmental branches