1999 年 75 巻 6 号 p. 315-317
During the dissection of the posterior compartment of the left leg, an unusual flexor hallucis longus muscle of a fifty two years-old male cadaver was observed. On the medial side of the flexor hallucis longus, on its lower distal half, a prominent aponeurotic structure was observed. A small unusual muscle mass was attached to this aponeurotic structure. The muscular fibres of the unusual mass were arranged in form of bipennate muscle. It originated via a broad tendon from the muscular fibres of the tibialis posterior and the deep transverse fascia covering the same muscle. It inserted on the aponeurosis of the lower medial half of the flexor hallucis longus muscle. Having in mind the very different pathology in the region of the ankle and the foot, the significance of such a musde mass could be of practical importance.