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The major nerves and vessels supplying and draining the upper limb
to axillary artery obstruction. The principal arteries involved are the
pass through the axilla.
The axilla is a three-sided pyramid. Its apex is the small region
suprascapular, from the third part of the subclavian artery, and the sub-
scapular, from the third part of the axillary artery with contributions
between the 1st rib, the clavicle and the scapula through which the anastomosis. It compensates for compromised flow that may occur due
major nerves and vessels pass. from other arteries.
The walls of the axilla are composed as follows: • The axillary vein: is formed by the confluence of the venae comit-
• The anterior wall is made up from the pectoralis major and minor antes of the axillary artery and the basilic vein (p. 69). It becomes the
muscles and the clavipectoral fascia. subclavian vein at the lateral border of the 1st rib. The named tributar-
• The posterior wall is made up of the subscapularis, teres major and ies of the axillary vein correspond to those of the axillary artery.
latissimus dorsi. • The cords and branches of the brachial plexus: see p. 71.
• The medial wall consists of the upper part of serratus anterior, the • The axillary lymph nodes: see p. 69.
upper ribs and intercostals. • Fat.
• The lateral wall is almost non-existent but can be seen as the latis-
simus dorsi as it inserts into the floor of the intertubercular (bicipital) Axillary clearance
sulcus. Running downwards from above are the corachobrachialis and In breast cancer surgery the axillary lymph nodes are cleared rou-
short head of biceps as well as the long head of biceps in the intertuber- tinely. During the dissection for this procedure one must clearly iden-
cular sulcus. tify the axillary vein, and the thoracodorsal (C6,7,8) and long thoracic
(C5,6,7) nerves. Injury to the thoracodorsal nerve results in paralysis
The contents of the axilla (Figs 33.1 and 33.2) of latissimus dorsi. Injury to the long thoracic nerve causes paralysis of
• The axillary artery: an important anastomosis exists between the serratus anterior resulting in weakened arm abduction. On clinical
subclavian artery and third part of the axillary arteryathe scapular examination the latter injury results in winging of the scapula.

The axilla 77