Mammary Gland Anatomy and Drainage

The internal thoracic artery is a major blood vessel that supplies the mammary gland. Perforating branches from this artery penetrate the gland tissue, delivering oxygen and nutrients.

The lateral thoracic artery, branching from the axillary artery, provides blood supply to the lateral aspect (sides) of the mammary gland.

Superior thoracic and acromiothoracic arteries, both originating from the axillary artery, contribute to the blood supply of the mammary gland, primarily the upper regions.

Intercostal arteries, found between the ribs, also play a role in supplying the mammary gland.

The subareolar plexus, a network of lymphatic vessels, originates beneath the areola (the dark area around the nipple) of the mammary gland.

The deep lymphatic plexus originates from a network of vessels found on the deep fascia, the tough connective tissue covering the pectoralis major muscle.

The majority of lymphatic vessels from the mammary gland drain into the axillary nodes, located in the armpit region.

A smaller proportion, around 25%, of the lymphatic vessels from the mammary gland drain into the parasternal nodes, located beside the breastbone.

The lateral part of the mammary gland drains towards the pectoral group of axillary nodes, then further to the apical group, located at the top of the armpit.

The upper region of the breast drains directly to the apical group of axillary nodes, skipping the pectoral group.