Achilles tendon insertion: an in vitro anatomic study.

Seventeen adult fresh-frozen below-knee amputation cadaver specimens were studied. Calcific Achilles tendinitis was present in three specimens. After exposing the Achilles tendon insertion on the calcaneus, the insertion was outlined with waterproof paint. The specimens were photographed on a special plexiglass apparatus to highlight important findings. For the purpose of showing the length of insertion on lateral radiographs, lead beads were placed on the most superior and most inferior aspects of the insertion. All specimens showed that the tendon terminated at the medial and lateral bone borders of the calcaneus without significant extension around the medial or lateral wall. All specimens revealed a greater distance of insertion on the medial calcaneus than on the lateral side. In the specimens that had calcific Achilles tendinitis, the posterior bone surface of the spurs was devoid of tendinous insertion, instead, the insertion occurred between the spur and the posterior wall of the calcaneus. All spurs were located laterally at the most inferior border of the tendon insertion.