Lymphatics arise in the form of a network of lymph capillaries which lie in the minute intercellular spaces of the body, and in addition form large lymph cavities, such as the peritoneal, pleural, &c. The lymph is then conveyed by larger and larger vessels, to the venous system, on entering which it mixes with the blood. The lymph of the left side of the trunk, of both legs, of the left arm, and the whole of the chyle is conveyed into the blood by the thoracic duct; while the lymph of the right side of the head, neck, and trunk, and of the right arm, enters the circulation at the junction of the axillary and internal jugular veins on the right side by a short trunk, guarded at its opening by valves. On its way the lymph passes through small glands of the size of a pea or bean called lymphatic glands. Thus, those of the arm pass through the lymphatic glands of the axilla, those of the leg through the glands of the groin, and those of the head and face through the glands of the neck.
The lymph arises primarily from the fluid part of the blood which exudes from the capillaries, bathes the cells and tissues of the body, and then, after supplying them with food and receiving their excretions, passes on once more to enter the circulation, being carried there by the lymphatic vessels. The corpuscular elements are chiefly the products of the lymphatic glands. See CHYLE, CIRCULATION.