Brachial Plexus I & II

Question 1

Components

Answer 1

Real Teachers Drink Cold Beer

Roots
Trunks (upper, middle, lower)
Divisions (anterior, posterior)
Cords (lateral, posterior, medial) 
Branches (MARMU

Question 2

Roots

Answer 2

C5 provides small contribution to the phrenic nerve
Dorsal scapular nerve: from the posterior aspect of C5 root; innervates the lower portion of the levator scapulae and the rhomboideus minor and major
Long thoracic nerve: from C5-7

Question 3

Trunks

Answer 3

Formed near the lateral border of the scalene muscles in the posterior triangle of the neck

Upper trunk: formed by union of C5 and C6. only trunk to have branches, suprascapular nerve: innervates supraspinatus and infraspinatus, nerve to subclavius
Middle trunk: continuation of C7
Lower trunk: formed by union of C8 and T1

Question 4

Divisions

Answer 4

Trunks are short and split into anterior and posterior divisions

Question 5

Cords

Answer 5

named for relation to axillary artery

Lateral cord: formed by union of the anterior divisions of the upper and middle trunks
Medial cord: formed by the anterior division of the lower trunk
Posterior cord: union of all 3 posterior divisions (behind the axillary artery)

Question 6

Branches

Answer 6

Lateral cord (3 branches)

Medial cord (6 branches)

Posterior cord (5 branches)

Question 7

Lateral cord

Answer 7

Lateral pectoral nerve (C5-7); Musculocutaneous nerve (C5-7); Lateral contribution to the median nerve (C6-7)

Question 8

Medial cord

Answer 8

Medial pectoral (C8, T1); medial brachial cutaneous (C8, T1); medial antebrachial cutaneous (C8, T1); Ulnar (C8, T1); Medial contribution to the median nerve (C8)

Question 9

Posterior cord

Answer 9

Upper subscapular (C5); thoracodorsal (C6-8); lower subscapular (C6); Axillary C5-6); Radial (C5-8, T1)

Question 10

Erb’s Palsy

Answer 10

Upper root damage

Waiters tip

Question 11

Klumpke’s Palsy

Answer 11

lower root damage (claw hand)

causes damage to radial, median, and ulnar nerves. This screws up all lumbricals and interossei, casuing inability to fully extend the digits.