Gibbon with epiphora

Radiographs of a White Cheeked Gibbon were taken because of epiphora on the right side.

The cause for epiphora was not seen, but an unusual radiographic feature was the presence of air [gas opacity] in the temporal bones.


The explanation for this was found after searching for an explanation in the literature. The Great Apes have naturally pneumaticised mastoid processes of the temporal bones. In this Gibbon the extent of pneumaticisation of skull bone is quite extensive, as seen on these images.

A variable degree of pneumaticisation of the temporal bone is seen in humans.  The following reference is provided for interest: Pneumatic Processes in the Temporal Bone of Chimpanzee (Pan troglodytes) and Gorilla (Gorilla gorilla), Journal of Morphology 241:127-137 (1999).

Graeme Allan. October 2010





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