Anatomy of Lower Limb

Abstract

In order to understand the pathophysiology of vascular edema, one should comprehend the anatomy of the veins and lymphatics that drain the lower limb. In this chapter, the organization of venous and lymphatic systems is described, together with embryological development of the lower extremity veins, which is of particular importance if anatomical variants are associated with limb swelling. Veins of the lower extremity can be categorized into three hierarchically ordered groups: the superficial, interfascial, and deep ones. Superficial veins are defined as veins located above the superficial fascia. Deep veins are located below the muscular fascia. Interfascial veins are enclosed by these two fibrous layers. Deep and interfascial veins, and sometimes deep and superficial ones, are interconnected by perforating veins, which are defined as veins penetrating the muscular fascia. There are also several important connections between the pelvic and lower extremity veins, which comprise the inguinal, obturator, perineal, and gluteal points. There are two main lymphatic outflow routes from the lower extremity: one runs superficially at the middle aspect of extremity toward the superficial inguinal lymph nodes; the other originates in the calcaneal region and runs toward the popliteal lymph nodes, and then to the deep or superficial inguinal lymph nodes. Deep inguinal lymph nodes primarily receive lymph coming from the popliteal nodes. Superficial inguinal lymph nodes comprise the horizontal and vertical groups. The horizontal group drains the lower part of the anterior wall of the abdomen, external genitals, and gluteal region. The vertical group drains the majority of the lower extremity.