Unusual case report of seven-headed quadriceps femoris muscle.

We present a case of a seven-headed quadriceps femoris (QF) muscle and a systematic review of the literature concerning this anatomical variation. During a routine dissection of the lower limbs of a 72-year old cadaver, a QF with supernumerary heads was identified. Each head of the muscle was photographed and subjected to further measurement. In addition to the four traditional heads of the QF muscle, we found a tensor of the vastus intermedius (TVI) muscle and two additional muscle bellies composed of tendons. Attachments of the TVI tendon and additional tendons were localized on the superior medial border of the patella. It is important to be aware of morphological variability of the quadriceps femoris muscle. The described case assists clinicist with avoiding misdiagnoses around the knee.