The transcondylar approach is being increasingly used to access lesions
ventral to the brain stem and cervicomedullary junction. Understanding the anatomy
of the occipital condyles is important for this approach. The present work aimed to
clarify the morphometric data of the occipital condyle and its importance in
transcondylar approach. The study was performed on 200 occipital condyles of 100
adult human dry skulls of unknown age and sex. Metric and morphological analysis
was performed for the specimens. The parameters were, the length, width, height, the
anterior and posterior inlercondylar distances and the distances from the occipital
condyle to the midline of the foramen magnum. En addition, the different locations of
the hypoglossal canal orifices relative to the occipital condyle were assessed. The
different shapes of the occipital condyles and their rates were detected. The length,
width and height of the occipital condyle were found to be 23.5, 13.58 and 9.64 mm
in the right and 23.75, 13.62 and 9.5mm in the left respectively. The anterior and
posterior intercondylar distances were 20.64 and 41.4mm respectively. The
intracranial orifice of hypoglossal canal was found to be present against the junction
of the 2nd and quarter or against the 3rd
quarter of the occipital condyle in 65%. The
extracranial orifice of the hypoglossal canal was found to be present against the
junction of the 1st
and 2nd quarter or against the 2d quarter of the occipital condyle in
69%. The more frequent type of occipital condyle detected is kidney shaped. It could
be concluded that, the safest area to be drilled in the occipital condyle is the posterior
quarter (4.5-78mm from the posterior end) as there is no location for the hypoglossal
canal orifice was found against this area. In the other locations the extent of bony
resection of the occipital condyle can be anticipated by the available recent
radiological techniques by using the meicioiiJ5örphometric parameters.

Keywords: Occipital condyle, hypoglossal canal, foramen magnum, transcondylar
approach.