Lateral intermuscular septum of the thigh and short head of the biceps femoris muscle: an anatomic investigation with new clinical applications.

An anatomic study was performed to reappraise the vasculature of the lateral intermuscular septum of the thigh and muscles associated with it using 12 preserved cadaver legs. Several possible new clinical applications of the lateral intermuscular septum and the short head of the biceps femoris were identified as follows: (1) short head of biceps femoris muscle or musculoseptal flap based on the second and/or third profunda perforating vessels, or based on the superior lateral genicular vessels, with or without the iliotibial tract and the deep fascia, and with or without the motor nerve of the short head; (2) transverse extension of the fascial portion of the tensor fasciae latae muscle or musculocutaneous flap to include the lateral intermuscular septum; (3) combination use of items 1 and 2, above; and (4) free septofascial graft using the lateral intermuscular septum and iliotibial tract. It is anticipated that the distally based short head of the biceps femoris muscle flap will be an additional option for repairing defects around the knee, and that a free short head of the biceps femoris muscle flap based on the profunda femoris perforating vessels will be useful in functional reconstruction such as reanimation of the paralyzed face. The lateral intermuscular septum can be incorporated into the short head of biceps femoris muscle flap or into the tensor fasciae latae flap, and it also can be used as a free fascial graft. Functional deficit resulting from harvesting the short head of the biceps femoris and the lateral intermuscular septum is minimal, and donor wound at the lateral lower thigh seems to be acceptable.