Breast

The term breast, also known by the Latin mamma in anatomy, refers to the upper ventral region of an animal's torso, particularly that of mammals, including human beings. Furthermore, the breasts are parts of a female mammal's body which contain the organs that secrete milk used to feed infants.

Anatomy

A woman's breasts sit over the pectoralis major muscle and usually extend from the level of the 2nd rib to the level of the 6th rib anteriorly. The superior lateral quadrant of the breast extends diagonally upwards in an 'axillary tail'. A thin layer of mammary tissue extends from the clavicle above to the seventh or eighth ribs below and from the midline to the edge of the latissimus dorsi posteriorly.

Related Topics:
Pectoralis major - Mammary tissue - Clavicle - Latissimus dorsi

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Important parts of the breasts include mammary glands, the axillary tail (tumours can occur here), the lobules, Cooper's ligaments, the areola and the nipple. The nipple is supplied by the T4 dermatome.

Related Topics:
Mammary gland - Axillary tail - Tumours - Cooper's ligaments - Areola - Nipple - Dermatome

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The development of a womans breasts, during puberty, is caused by sex hormones, chiefly estrogen. This hormone has been demonstrated to cause the development of woman-like, enlarged breasts in men, a condition called gynecomastia, and is sometimes used deliberately for this effect in male-to-female sex reassignment surgery.

Related Topics:
Puberty - Sex hormone - Estrogen - Gynecomastia - Male-to-female - Sex reassignment surgery

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The arterial blood supply to the breasts is derived from the internal thoracic artery (previously referred to as the internal mammary artery, lateral thoracic artery, thoracoacromial artery, and posterior intercostal arteries. The venous drainage of the breast is mainly to the axillary vein, but there is some drainage to the internal thoracic vein.

Related Topics:
Internal thoracic artery - Lateral thoracic artery - Thoracoacromial artery - Posterior intercostal arteries - Axillary vein - Internal thoracic vein

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The breast is innervated by the anterior and lateral cutaneous branches of the 4th through 6th intercostal nerves.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Lymphatic drainage

As breast cancer is a common cancer, the lymphatic drainage of the breast (sites where cancer may metastasize) is important.

Related Topics:
Breast cancer - Cancer - Lymphatic drainage - Metastasize

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

About 75% of lymph from the breast travels to the ipsilateral (same side) axillary lymph nodes. The rest travels to parasternal nodes, to the other breast, or abdominal lymph nodes.

Related Topics:
Lymph - Lymph node

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The axillary nodes include the pectoral, subscapular, and humeral groups of lymph nodes. These drain to the central axillary lymph nodes, then to the apical axillary lymph nodes.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~