Introduction: the axilla is a pyramidal shape at the junction of the arm and the thorax. It is bounded anteriorly and posteriorly by the axillary folds and communicate superiorly with the posterior triangle of the neck. It provides a passage way for the large nerve and vessels to reach the upper limb.
Extent: from the root of the neck to the fourth rib.
Boundaries: the axilla has an apex, a base and 4 walls.
Apex: the apex is bounded by the clavicle, scapula, and the outer border of the first rib. It is located at the medial side of the root of the coracoid process. It is the channel of communication between the axilla and the posterior triangle of the neck.
Base: it’s formed by the fascia and skin of the axilla. The base of the axilla faces inferiorly and the skin contains hair in postpubertal persons
Anterior wall: this is formed by the clavicle, pectotalis major and minor, subclavius and the clavipectoral fascia.
Posterior wall: this is formed by subscapularis and trees major muscles, the tendon of the latissimus dorsi and the scapula.
Medial wall: this is formed by ribs and intercostal muscles covered by the serratus anterior muscle.
Lateral wall: this is formed by the floor of the intertubercular groove in the humerus.
Content of the axilla:
– the three cords and branches the bronchial plexus
– the axillary artery and branches
– the axillary vein and its tributaries
– the axillary lymph nodes.