Of these the calcaneum is the fibulare, and the astragalus is generally regarded as the tibiale and intermedium fused.
The calcaneum does not articulate with the fibula, except in Macrauchenia.
Moreover the fibula when present does not as a rule articulate with the calcaneum.
The calcaneum has a large facet for articulation with the fibula, as in Artiodactyla.
It then winds round the latter in placing itself on its inner side, then on its posterior surface, and reaches the calcaneum.
The fibula articulates with the calcaneum, and the astragalus is very flat.
The calcaneum resembles that of Artiodactyles in having a small facet for articulation with the fibula.
It arises from the calcaneum, and passes to the four outer toes.
In the tarsus the cuboid articulates with both the calcaneum and the astragalus, which is remarkably flat.
However, they pass from this region but to be soon continued by a tendon—the tendo-Achillis, which is inserted into the calcaneum.