Key to Diagram:

First division - one branch:
    (1)  Supreme Thoracic Artery

Second division - two branches:
    (2)  Thoracoacromial (with four smaller branches)
        A.  Pectoral Branch
        B.  Deltoid Branch
        C.  Acromial Branch
        D.  Clavicular Branch
    (3)  Lateral Thoracic Artery

Third division - three branches:
    (4)  Subscapular Artery (branches to the Circumflex Scapular Artery and
            the Thoracodorsal Artery)
    (5)  Anterior Humeral Circumflex Artery
    (6)  Posterior Humeral Circumflex Artery (which passes through the
            quadrangular space)

Reference Netter Plates 398 and 405.