The axilla is defined by several muscular and skeletal landmarks that shift shape with shoulder movement:
: 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.
The cavity is filled with fat and connective tissue, which cushions several major structures: axillary cavity
: Formed by the subscapularis , teres major , and latissimus dorsi muscles.
: Consists of the serratus anterior muscle and the first four or five ribs. The axilla is defined by several muscular and
: Formed by the axillary fascia and the skin of the armpit.
: Primarily composed of the pectoralis major and pectoralis minor muscles. formed by the first rib
Anatomy, Shoulder and Upper Limb, Axilla - StatPearls - NCBI