|Nerve||axillary nerve, medial cord, posterior cord, lateral cord|
|Lymph||axillary lymph nodes|
In humans, the formation of body odor happens mostly in the axillary region. These odorant substances serve as pheromones which play a role related to mating. The underarm regions seem more important than the genital region for body odor which may be related to human bipedalism.
Anatomically, the boundaries of the axilla are:
|superiorly: by the outer border of first rib, superior border of scapula, and posterior border of clavicle|
|medially: serratus anterior and by the ribcage||anteriorly: by the pectoralis major, minor, and subclavius||laterally: by the intertubercular sulcus (coracobrachialis and the short head of the biceps brachii are in the axilla.)|
|floor/base: by the skin (visible surface of axilla)|
The anterior boundary is called the anterior axillary fold and this is rounded in shape and formed by the lower border of the pectoralis major. Some sources also include the pectoralis minor.It can elongate after weight loss.
The term "underarm" typically refers to the outer surface of the axilla. However, the terms are sometimes used interchangeably in casual contexts. Colloquially, underarm refers to the hollow beneath the junction of the arm and shoulder.
The underarm can be a ticklish area, possibly due to the number of nerves it contains. Some people find this area to be particularly unpleasant when tickled.
In some modern Western cultures, it is common for women to remove underarm hair. Some view this practice as an aesthetic matter, while others view its removal as a possible effect of health related concerns. As underarm hair grows quickly, shaving must be performed frequently, or else stubble will appear in the axilla.
Throughout the feminist movement, previously in the hippie culture, and in some areas of the punk rock scene, some women choose to keep their underarm hair for a variety of reasons, from subversion to egalitarianism to comfort. Conversely, some men choose to remove their underarm hair for similar aesthetic reasons or to reduce friction in some sports, such as swimming.
Breast cancer typically spreads via lymphatic vessels to the lymph nodes found in the axilla.
Excessive perspiration can result in axillary intertrigo. Intertrigo is an inflamed skin condition caused by heat, friction, and moisture. A warm, wet underarm may accommodate the growth of pathogenic bacteria, yeasts, and fungi. The condition is responsible for rash-like symptoms, pustules, or chronic itching or burning in the underarm. Axillary intertrigo is common among those who work in hot environments.
|Anatomy of the axilla|
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