NEET PG Medical – 2014 – Question – 12
Posterior wall of axilla is formed by
a) Pectoralis major
b) Pectoralis major
c) Subscapularis
d) Intercostal muscles
Correct Answer – C
Axilla (armpit)
- The axilla is apyramidal space situated between the upper part 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).
1. Anterior (pectoral) wall :- Formed by (i) Pectoralis major, (ii) Pectoralis minor, and (iii) Subclavius. The latter two muscles
enclosed by clavipectoral fascia.
2. Posterior (subscapular) wall :- Formed by (i) Subcapularis, (ii) Teres major, and (iii) Latissimus dorsi.
3. Medial (thoracic) wall :- Formed by (i) Upper four ribs (with their intercostal muscles), and (ii) Upper part of serratus anterior.
4. Lateral (humeral) wall :- Formed by (i) Upper part of humerus with bicipital groove lodging the tendon of long head of biceps, and (ii) Corachobrachialis and short head of biceps ?
5. 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 part of scapula and medially by outer border of first rib. The axillary artery and brachial plaxus enter the axilla through this canal.
