Axilla - summary and muscles (dave's notes)

Question 1

Define the axilla

Answer 1

The space between the upper arm and side of the thorax, bounded in front and behind by the axillary folds.

Question 2

What does the axilla communicate with above?

Answer 2

The posterior triangle of the neck

Question 3

What does the axilla contain?

Answer 3

Neurovascular structures and lymph nodes for the upper limb and side wall of the thorax

Question 4

What is the floor of the axilla?

Answer 4

The axillary fascia - this extends from serratus anterior fascia to the fascia of the forearm

Question 5

What suspends the floor of the axilla? What are its anterior and posterior attachments?

Answer 5

The axillary fascia is suspended by the suspensory ligament, and is attached in front and behind by axillary folds.

Question 6

What forms the anterior wall of the axilla?

Answer 6

Pectorals, subclavius and the clavipectoral fascia

Question 7

What forms the posterior wall of the axilla? How does it differ to the anterior wall?

Answer 7

The posterior wall extends lower, formed by subscapularis and teres major

Question 8

What forms the medial wall of the axilla?

Answer 8

Serratus anterior

Question 9

What forms the apex of the axilla?

Answer 9

The apex is bound by the clavicle, scapula and the outer border of the first rib

Question 10

What are the muscles of the axilla?

Answer 10

Subscapularis and teres major

Question 11

What is the origin and insertion of subscapularis?

Answer 11

Originates from the medial two thirds of the sub scapular fossa, inserts into the lesser tuberosity of the humerus, upper medial lip of the bicipital groove, and the capsule of the shoulder joint

Question 12

What is the action and innervation of subscapularis?

Answer 12

Medially rotates the arm and stabilises the shoulder joint. Nerve is the upper and lower sub scapular nerve from C5,6, from the posterior cord

Question 13

What is the origin and insertion of trees major?

Answer 13

The oval area (lower third) of the lateral side of the inferior angle of the scapula below teres minor.
Inserts into the medial side of the bicipital groove of the humerus

Question 14

What is the action and innervation of teres major

Answer 14

Medially rotates and adducts the arm, stabilises the shoulder joint. The nerve is the lower scapular nerve (C5,6,7) from the posterior cord. Note - functionally part of subscapularis