Ketiak

Ketiak, commonly spelled ketiak in Malay and Indonesian, refers to the armpit—the region beneath the shoulder joint where the upper arm meets the chest wall. It is a small but structurally complex area that contains skin, subcutaneous tissue, hair follicles, and a dense network of sweat glands and lymph nodes. The armpit is bounded by the anterior and posterior axillary folds and lies near the axillary vessels and nerves.

Two main types of sweat glands are found in the ketiak: eccrine glands, which help regulate body temperature, and apocrine glands, which become active after puberty and are associated with hair follicles. Apocrine secretions, in combination with skin bacteria, can produce odor. The armpit also contains axillary lymph nodes that drain lymph from the upper limb and chest wall, contributing to immune defense. Blood supply mainly comes from branches of the axillary artery, and sensory innervation includes the intercostobrachial nerves.

Common considerations include hygiene and grooming, deodorants and antiperspirants, and the potential for skin irritation, infections, folliculitis, or hidradenitis suppurativa. Shaving, waxing, or friction can influence skin irritation and hair growth patterns in the ketiak. The term ketiak is used in Malay and Indonesian, with “armpit” or “axilla” as the equivalents in English.