Topic 19 - Axillary, Musculocutaneous & Median Nerves

Question 1

A nerve that originates from C5/C6 nerve roots and the posterior cord of the brachial plexus.

Answer 1

Axillary Nerve

Question 2

Which 2 muscles are innervated by the axillary nerve?

Answer 2

Deltoid
Teres Minor

Question 3

What are the 2 motor functions of the axillary nerve?

Answer 3

Abduction of arm at shoulder
External rotation of arm at shoulder

Question 4

T/F - The axillary nerve is responsible for the first 15 degrees of abduction of the arm at the shoulder.

Answer 4

False - The axillary nerve is responsible for abduction of the arm at the shoulder BEYOND the first 15 degrees.

Question 5

What is the sensory distribution for the axillary nerve?

Answer 5

Skin over the superolateral shoulder over deltoid

Question 6

The axillary nerve branches off the large ______ nerve and exits the axilla through the _____________ space.

Answer 6

Radial
Quadrilateral (aka. Quadrangular)

Question 7

Match the 4 boundaries of the quadrangular space with the corresponding structure:
1) Teres minor and subscapularis
2) Surgical neck of the humerus
3) Teres major
4) Long head of triceps

A) Medial
B) Lateral
C) Superior
D) Inferior

Answer 7

1) Teres minor and subscapularis = C) Superior
2) Surgical neck of the humerus = B) Lateral
3) Teres major = D) Inferior
4) Long head of triceps A) Medial

Question 8

T/F - The axillary nerve innervates the short head of triceps brachii, but it is not the sole provider.

Answer 8

False - The axillary nerve also innervates the LONG head of triceps brachii, but it is not the sole provider.

Question 9

T/F - The axillary nerve is the sole innervation for deltoids and teres minor.

Answer 9

True