Axillair

Axillair is an adjective used in some languages to describe structures or conditions related to the axilla, the armpit. In English and most medical literature, the corresponding terms are axillary or axilla. The axilla is a pyramidal space that sits beneath the shoulder joint and serves as a passage between the thorax and the upper limb, housing vessels, nerves and lymphatic tissue.

Boundaries of the axilla include the anterior wall formed by the pectoralis major and pectoralis minor, the posterior wall by the subscapularis, teres major and latissimus dorsi, the medial wall by the thoracic wall and serratus anterior, and the lateral boundary by the intertubercular groove of the humerus, with the apex at the cervico-axillary canal. Contents include the axillary artery (divided into three parts by the pectoralis minor), the axillary vein, branches of the brachial plexus, and axillary lymph nodes organized into groups such as lateral, central and apical. The region also contains fat and several nerves in close proximity.

Clinical relevance of the axilla includes its role in breast cancer staging, where sentinel lymph node biopsy or axillary lymph node dissection may be performed. Injury or compression of the axillary nerve can impair deltoid function and shoulder abduction. Lymph node enlargement or infection can reflect systemic or regional disease, influencing limb drainage and clinical management. Imaging tools such as ultrasound or MRI aid evaluation of the axilla in disease or trauma.