Unit 2 - Upper Limb: Brachial Plexus (Ex. II)

Question 1

pre-terminal nerves in trunks

Answer 1

S trunk:

• suprascapular n. (C4-C6) –> supraspinatus; infraspinatus
• n. to subclavius (C5-C6) –> subclavius

Question 2

What runs through plexus that separates divisions and cords?

Answer 2

axillary artery

Question 3

Cords are named relative to what landmark?

Answer 3

axillary artery

• L cord (superior-most)
• P cord (middle)
• M cord (inferior-most)

Question 4

pre-terminal nerves in cords

Answer 4

L cord:
- lateral pectoral n. (C5-C7) –> pectoralis major
P cord:
- thoracodorsal n. (C6-C8) –> latissimus dorsi
- upper subscapular n. (C5-C6) –> upper subscapularis
- lower subscapular n. (C5-C6) –> lower subscapularis; teres major
M cord:
- medial pectoral n. (C8-T1) –> pectoralis major and minor
- medial brachial cutaneous n. (T1) –> skin of M arm
- medial antebrachial cutaneous n. (C8-T1) –> skin of M forearm

Question 5

M
A
R
M
U

Answer 5

musculocutaneous n. (C5-C7) ==> L cord
axillary n. (C5-C6) ==> P cord
radial n. (C5-T1) ==> P cord
median n. (C6-T1) ==> L and M cords
ulnar n. (C7-T1) ==> M cord

Question 6

What terminal nerve branches form the “M?”

Answer 6

musculocutaneous n. (C5-C7) ==> L cord (L to axillary a.)
median n. (C6-T1) ==> L and M cords (on top of axillary a.)
ulnar n. (C7-T1) ==> M cord (M to axillary a.)

axillary and radial nn. come from P cord so lie deep to axillary a.

Question 7

supraclavicular segment

Answer 7

contains roots and trunks

Question 8

infraclavicular segment

Answer 8

contains divisions, cords, and branches

Question 9

Remember
To
Drink
Cold 
Beer

Answer 9

roots ==> trunks ==> divisions ==> cords ==> branches

Question 10

pre-terminal nerves in roots

Answer 10

dorsal scapular n. (C4-C5) –> levator scapulae; rhomboids

long thoracic n. (C5-C7) –> serratus anterior