Return to the axilla and identify the remaining branches of the axillary artery and the brachial plexus. Observe that most of the branches are oriented along an axis passing from the apex of the axilla (proximal) towards the anterior-medial aspect of the arm (distal). (G 2.27A;N 415;Gl 28.34)

1. Reflect the pectoralis minor muscle in the superior direction. Identify the subscapular artery (G 2.27A;N 420;Gl 28.34B) branching from the axillary artery. Trace its two major branches, the circumflex scapular artrey (dives deep to reach the posterior aspect of the scapula) and the thoracodorsal artery (descends to reach the latissimus dorsi muscle; trace the latissimus dorsi to its distal attachment on the medial lip of the bicepital groove).
2. Identify the anterior and posterior circumflex humeral arteries. (G 2.27A;N 420;Gl 28.1B) The anterior circumflex humeral artery is typically the smaller of the two arteries. The posterior circumflex humeral artery occasionally arises from the subscapular artery. Remember, we name the arteries for the structures they supply (where they go) even if they do not follow the typical branching pattern illustrated in the atlas. (G 2.24;N 420;Gl 28.1B)
3. Stop tracing the axillary artery at the level of the humeral attachment of the latissimus dorsi muscle.