: The top of the pyramid, formed by the first rib , the scapula , and the clavicle . It connects the axilla to the posterior triangle of the neck.
: Formed by the subscapularis , teres major , and latissimus dorsi muscles. axillary cavity
: Formed by the axillary fascia and the skin of the armpit. : The top of the pyramid, formed by
: Consists of the serratus anterior muscle and the first four or five ribs. : The top of the pyramid