random facts

Question 1

dermatome

Answer 1

area of skin innervated by a specific spinal n. level (each brachial plexus root has an associated dermatome.

Question 2

myotome

Answer 2

movement associated with a specific spinal n. level (motor neurons from each BP root course to associated upper limb myotome with an associated movement).

Question 3

Which roots course above their associated vertebra?

Answer 3

C5-C8 (We have 8 cervical nerves and 7 cervical vertebra. The C8 n. courses below C7 and above T1. Then everywhere below T1, the nerve courses below the vertebra)

Question 4

Myotome C5

Answer 4

shoulder abduction

Question 5

Myotome C6

Answer 5

elbow flexion

Question 6

Myotome C7

Answer 6

elbow extension

Question 7

Myotome C8

Answer 7

finger flexion

Question 8

Myotome T1

Answer 8

finger abduction

Question 9

how do the roots and trunks relate to surrounding anatomy?

Answer 9

exit between anterior and middle scalene mm. The subclavian artery is also between these mm.

Question 10

Why are there Divisions of the brachial plexus?

Answer 10

embryology - limb bud with dorsal and ventral mm mass; anterior divisions sends axons to ventral m mass (flexors); posterior sends motor neurons to innervate extensors.

Question 11

ventral mm mass innervates which hand muscles?

Answer 11

intrinsic (dorsal m mass ends in forearm)

Question 12

The 3 Cords are named in relationship to what?

Answer 12

cords are named for their position in relation to the axillary artery.