axillaren

Axillaren, in anatomical terms, refers to the axilla or armpit region. It is a pyramidal space that serves as a passageway between the thorax and the upper limb, containing vessels, nerves, lymphatics, and adipose tissue. The axilla acts as a transitional zone through which the upper limb receives its blood supply and nerve innervation while maintaining lymphatic drainage from the arm and portions of the chest and breast.

The borders of the axillaren define its boundaries: the anterior wall is formed primarily by pectoralis major and pectoralis minor, the posterior wall by subscapularis, teres major, and latissimus dorsi, the medial wall by the rib cage and upper thoracic wall, the lateral wall by the intertubercular groove of the humerus, and the apex, or cervicoaxillary tunnel, near the thoracic inlet. The base is the skin and fascia of the armpit. Within this space run the axillary artery and vein and their branches, the cords of the brachial plexus, axillary lymph nodes, adipose tissue, and portions of breast tissue and surrounding muscles. Sensory nerves such as the intercostobrachial nerve and several small motor nerves travel through or near the region.

Functions of the axillaren include supplying the upper limb with arterial blood, draining venous blood back toward the heart, and housing lymph nodes that filter lymphatic fluid and participate in immune responses. The axillary lymph nodes are clinically important, particularly in breast cancer staging and metastasis assessment, where sentinel lymph node biopsy can be used.

Etymology derives from the Latin axilla, meaning armpit. The region is routinely imaged via ultrasound or MRI when pathology or trauma is suspected.