The axilla extends from the first rib to the lower margin of the posterior axillary fold (= the lower border of the teres major muscle)
Posterior wall is the subscapularis, teres major and latissimus dorsi muscles
Anterior wall is the major and minor pectoral muscles
The lateral wall is the humerus and the tendons of the short head of the biceps muscle and the coracobrachialis muscle
Posterior wall (white asterix): subscapularis, teres major and latissimus dorsi muscles. Anterior wall: major & minor pectoral muscles (yellow and cyan asterixs). Lateral wall: humerus and the tendons of the short head of the biceps and coracobrachialis muscles (blue arrow). Medial wall: serratus anterior (green arrows).
