The role of the lateral upper arm bundle and the lymphatic watersheds in the formation of collateral pathways in lymphedema.

The study of possible drainage pathways for the upper extremity after axillary lymphadenectomy by means of Indian ink injection shows: 1) that the single drainage is through the lateral upper arm bundle, but only if the latter joins the supraclavicular nodes or if its infraclavicular ending remains unremoved; 2) that the lateral bundle occur as either a long or a short type; 3) that with regard to the lymphatic drainage of the skin, areolae, zones and territories can be distinguished; 4) that a long bundle is the more suitable collateral way as collectors of the forearm territory join it; 5) that the most frequent cause of lymphedema is the fact that lymph of the forearm as well as of the dorsomedial upper arm territory can reach the lateral bundle only via the cutaneous plexus, over the lymphatic watersheds.