intertarsal-type crurotarsal jointGo to external page http://purl.obolibrary.org/obo/UBERON_0016882
An ankle joint that passes between the astragalus and calcaneum. [ http://palaeos.com/vertebrates/glossary/glossaryCr.html#Crurotarsal%20joint ]
An ankle joint that passes between the astragalus and calcaneum.
The ankle joint of pseudosuchians (including crocodilians) and phytosaurs, passing between the astragalus and calcaneum, is also called crurotarsal joint in the literature. In the skeletons of the phytosaurs and most of the pseudosuchians this joint bends around a peg on the astragalus which fits into a socket in the calcaneum (the 'crocodile normal' tarsus); only in the skeletons of the ornithosuchid pseudosuchians a peg on the calcaneum fits into a socket in the astragalus (the 'crocodile reversed' tarsus). Strictly speaking this ankle isn't a crurotarsal joint in the previously discussed sense, as it's situated between the two proximal tarsal bones. However, while calcaneum isn't fixed to the fibula, the astragalus is fixed to the tibia by a suture and thus in practice it functions as an extension of the crus.