The hand and fingers are abundantly supplied with lymphatics which begin in a plexus around the matrix of the nail and the pulp of the fingers and unite to form lymphatic trunks which proceed up the wrist and forearm. There are both superficial and deep sets, which communicate at the wrist.

The deep set follows the arteries of the forearm and arm to the axilla. This set sometimes possesses a few nodes in the forearm and one at the flexure of the elbow.

The superficial set, both anteriorly and posteriorly, concentrates in the supratrochlear nodes and thence proceeds to the axilla. Some of the lymphatic vessels pass by the supratrochlear nodes and empty direct into the axillary nodes (Fig. 382).

In infections of the fingers or hand the infection follows the lymphatic trunks, which can be seen as red lines running up the forearm. Suppuration may involve the supratrochlear and, later, the axillary nodes. As some of the lymphatic trunks pass by the supratrochlear nodes to empty direct into the axillary nodes there may be infection of the latter without any implication of the former. Enlargement and inflammation of the occasionally present deep lymphatic nodes of the forearm is clinically unknown, so it may be said that practically there are no lymphatic nodes below the supratrochlear ones.

Fig. 382.   Superficial lymphatic vessels of upper limb; semidiagrammatic. (Based on figures of Sappey).

Fig. 382. - Superficial lymphatic vessels of upper limb; semidiagrammatic. (Based on figures of Sappey).