The neurovascular territories of the skin and muscles: anatomic study and clinical implications.

In 1987, the results of a series of total-body investigations of the arterial system of the skin and underlying deep tissues were published. This resulted in the angiosome concept. In 1990, a similar series of studies of the venous network was published. In both investigations, it was noted that "vessels hitchhike with nerves." This anatomic study analyzes these neurovascular relationships in the skin and in the underlying muscles. Seven fresh human cadavers and nine animals were studied over a 2-year period. The entire integument of each and a total of 538 human and 72 animal muscles were removed and analyzed. Either the arterial or the venous system was injected with a radiopaque lead oxide mixture, and the dissected nerves were labeled with fine wires, being segregated later by a subtraction radiography technique. The results of these investigations are presented, with special emphasis placed on the design of long axial skin flaps placed along neurovascular systems and their relationship with the current design of skin flaps. The muscles are classified according to their extrinsic and intrinsic neurovascular supplies, and suggestions are made as to how they may or may not be subdivided into functional units for local and distant transfer. The cutaneous nerves, as well as the motor nerves of the muscles, were invariably accompanied by a longitudinal system of arteries and veins that often was the dominant supply to the region. Whether the nerves appeared together with the vessels, whether the nerves crossed them at an angle, or whether they approached the vessels from opposite directions, in each case the main trunk of the vessel or some of its branches soon "peeled off" to course parallel to the nerve. This information provides the basis for the design of long skin flaps placed along neurovascular systems. Indeed, it reveals that many of the current "axial" or "fasciocutaneous" skin flaps used in clinical practice are in fact neurovascular flaps. The muscles are classified into four types according to their extrinsic and intrinsic neurovascular supplies. Type I muscles are supplied by a single unbranched nerve. In type II muscles, the nerve branches before entering the muscle. Type III muscles receive multiple motor nerves from the same nerve trunk, and type IV muscles are supplied from multiple nerve trunks. Suggestions are made as to how muscles of each type may or may not be subdivided into functional neurovascular units for local and distant transfer.(ABSTRACT TRUNCATED AT 400 WORDS)