Cavity | Axillary

: Formed by the axillary fascia and the skin of the armpit.

: Primarily composed of the pectoralis major and pectoralis minor muscles.

The , commonly referred to as the axilla or "armpit," is a four-sided pyramidal space located at the junction of the upper limb and the thorax. It serves as a vital gateway for neurovascular and lymphatic structures traveling between the neck/torso and the upper extremity. Anatomical Boundaries axillary cavity

The axilla is defined by several muscular and skeletal landmarks that shift shape with shoulder movement:

: Formed by the subscapularis , teres major , and latissimus dorsi muscles. : Formed by the axillary fascia and the skin of the armpit

: The narrowest part, formed by the intertubercular sulcus (bicipital groove) of the humerus. Core Contents

: 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. It serves as a vital gateway for neurovascular

: Consists of the serratus anterior muscle and the first four or five ribs.