A case report of rare variant: well-developed paracondylar process

The paracondylar process (PCP) is defined as the bony prominence extending from the outer side of the condyles on the outer surface of the occipital bone downwards towards the transverse process of the atlas (TPA). In this case report, the morphometry of the rarely seen PCP and its morphometric data with neighboring structures are evaluated.

Unilateral (right-sided) PCP was observed in the cranium of a Caucasian female. The base of the PCP, located on the outer side of the occipital condyle (OC) and just behind the jugular foramen (JF), was broader than its apex and had a molar shape. The base width was measured as 13.6, and the top width was measured as 8.7 mm. PCP length was measured at 15.2 mm. The base distance of the PCP, which was located very closely with the OC and JF, to these structures was measured as 0.42 and 0.59 mm, respectively. The distance to the spinous process (SP) and mastoid process (MP) of the temporal bone was relatively greater and was measured as 1.07 and 15.5 mm, respectively.

The rare PCP reported, in this case, was well-developed and molar type. It is likely large enough to articulate with the TPA regarding length. However, this could not be shown because the matched atlas could not be found. We believe that supporting the close adjacencies of PCP with OC and JF with metric data may benefit clinicians working in regional surgery.