Axilla Information & Axilla Links at HealthHaven.com

Axilla
	Deep muscles of the chest and front of the arm, with the boundaries of the axilla.
Latin	axilla
Gray's	subject #149 585
Artery	axillary artery
Vein	axillary vein
Nerve	axillary nerve, medial cord, posterior cord, lateral cord
Lymph	axillary lymph nodes
MeSH	Axilla

For the bowling style in cricket, see underarm bowling.

The axilla (or armpit, underarm, or oxter) is the area on the human body directly under the joint where the arm connects to the shoulder.

[edit] Boundaries

Anatomically, the boundaries of the axilla are:

	superiorly: by the outer border of first rib, superior border of scapula, and posterior border of clavicle^[1]
medially: serratus anterior ^[2] and by the ribcage	anteriorly: by the pectoralis major, minor,^[3] and subclavius ^[2] (see also anterior axillary fold) posteriorly: by the subscapularis above, and teres major and latissimus dorsi below^[2] (see also posterior axillary fold)	laterally: by the intertubercular sulcus ^[3] (coracobrachialis and the short head of the biceps brachii are in the axilla.)^[2]
	floor/base: by the skin^[1] (visible surface of armpit)

The contents of the axilla include the axillary vein and artery, as well as the brachial plexus, lymph nodes and fat.

[edit] Terminology

The term "underarm" typically refers to the outer surface of the axilla. However, the terms are sometimes used interchangeably in casual contexts. Colloquially, armpit refers to an object or place which is smelly, greasy or otherwise undesirable. ^[4]

The term oxter is most often used in the United Kingdom ^[5] and the Republic of Ireland. In Northern Ireland "oxter" generally replaces all other names for the armpit.

[edit] Underarm hair

Main article: Underarm hair

Underarm hair usually grows in the underarms of both females and males, beginning in adolescence.

In modern Western culture, it is common for women to remove underarm hair for aesthetic reasons. As underarm hair grows quickly, shaving must be performed frequently, or else stubble will appear.

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.

Researchers have discovered that women adjust their menstrual cycles when exposed to chemicals from the underarm.^[6]

[edit] Darkening of the underarms

Sometimes, shaving, buildup of dead skin cells which is caused by not scrubbing on a daily basis, antiperspirant usage, and hyper pigmentation contribute to giving the underarm a dark colour. Also, a medical condition known as acanthosis nigricans may also contribute to darkened underarms, although most people with dark underarms do not have this condition.^[7]

[edit] Axillary intertrigo

Excessive perspiration can result in axillary intertrigo. Intertrigo is an inflamed skin condition caused by heat, friction, and moisture.^[8] A warm, wet armpit may accommodate the growth of pathogenic bacteria, yeasts, and fungi.^[9] The condition is responsible for rash-like symptoms, pustules, or chronic itching or burning in the armpit.^[8] Axillary intertrigo is common among those who work in hot environments.^[9]

[edit] Miscellany

The axilla is one of the four sites (the other three being the mouth, rectum, and ear canal) in which a medical thermometer may be inserted in order to measure body temperature.
The underarms are among the locations in the human body which are most vulnerable to tickling.
The sexual attraction to the underarms is called axillism.