The quadriceps gastrocnemius muscle.

The gastrocnemius muscle forms the belly of calf muscles in the posterior compartment of the leg. This paper reports a four-headed gastrocnemius (named quadriceps gastrocnemius) muscle as a new variant and when present can alter the anatomy and/or the boundaries of the popliteal fossa. The four heads are named as medial, intermedio-medial, intermedio-lateral and medial. The newly identified heads, intermedio-medial and intermedio-lateral heads form the inferior boundaries of the popliteal fossa. Clinical conditions like popliteal entrapment syndrome may arise because of distal fossa congestion created by the intermedio-medial and intermedio-lateral heads. This supernumerary heads may also be useful for grafting and they also provide bulkier mass for gastrocnemius proximal attachment. The knowledge of anatomical variants presented is useful to surgeons, prosectors and radiologists.