Posterior wall of axilla is formed by
Axilla (armpit)The axilla is apyramidal space situated between the upper pa of the arm and the chest wall. It resembles afour sided pyramid, and has following : (i) an apex (ii) a base (iii) four walls (anterior, posterior, medial and lateral).Anterior (pectoral) wall :- Formed by (i) Pectoralis major, (ii) Pectoralis minor, and (iii) Subclavius. The latter two muscles enclosed by clavipectoral fascia.Posterior (subscapular) wall :- Formed by (i) Subcapularis, (ii) Teres major, and (iii) Latissimus dorsi.Medial (thoracic) wall :- Formed by (i) Upper four ribs (with their intercostal muscles), and (ii) Upper pa of serratus anterior.Lateral (humeral) wall :- Formed by (i) Upper pa of humerus with bicipital groove lodging the tendon of long head of biceps, and (ii) Corachobrachialis and sho head of biceps ?Base :- Formed by Skin, superficial fascia and deep (axillary) fascia. It is directed downwards.Apex :- It is directed upwards and medially towards the root of neck. It communicates with supraclavicular triangle of neck, hence referred to as Cervicoaxillary canal. It is triangular in shape and is bounded anteriorly by clavicle, posteriorly by upper pa of scapula and medially by outer border of first rib. The axillary aery and brachial plaxus enter the axilla through this canal.
Pectoralis major
Pectoralis major
Subscapularis
Intercostal muscles