nerves

Question 1

arrangement of nerves?

Answer 1

• Nerves exit the spinal cord through through the dorsal and ventral roots
• They enter the intervertebral foramen- mixed with sensory and motor neurones
• They enter the ventral rams which carries sensory and motor neurones to the anterolateral skin, bones and muscles AND the limbs
• or they enter the dorsal ramus which carries sensory and motor neurones to the posterior trunk.

Question 2

which muscles to the dorsal and ventral rami supply?

Answer 2

Dorsal- exits the spinal cord posteriorly to supply the erector spinal muscles and the skin around
Ventral- Exists the spinal cord laterally and anteriorly and supply the intercostal muscles (anterolateral thoracic) as well as the rectus and oblique abdomenis +upper and Lowe limbs

Question 3

How are the intercostal nerves names?
How many are there?
What else do they supply?

Answer 3

• The have the same number as the rib directly above them.
• There are twelve of them
• The last 6 intercostal nerves- T7-T12 also supply the anterior abdominal wall

Question 4

Dermatomes

Answer 4

Dermatomes are an area of skin which is supplied by one single spinal nerve. Adjacent dermatomes overlap– decay to one single spinal nerve with lead to deterioration of an area but not complete paralysis. Two adjacent nerves would have to be cut for this to happen.

Question 5

Cutaneous innervation

Answer 5

Area of skin over a muscle which is supplied by the same branch of nerves from the plexus as the muscle beneath it.
Contains nerves with different fibres.

Question 6

Different membranes around a nerve

Answer 6

Endoneurium- surrounds a single nerve fibre/axon
Perineurium-surrounds a nerve fascicle
Epineurium- surrounds multiple fasciscles
myelin sheath is inside an endoneurium

Question 7

What is the last intercostal nerve known as?

Answer 7

Subcostal nerve

Question 8

What are the intercostal nerves?

Answer 8

The nerves from the ventral rami which supply the muscle in between the ribs