Imaging and morphology of the paracondylar process in a dry adult human skull: a case report.

An unusually long paracondylar process (PCP) was found articulating with the transverse atlantal process in a dry adult male skull. It was 13 mm long and 19 mm in circumference at its middle and projected to a lower plane than the styloid process of the same side. A radiograph revealed the structure of spongiosa of the PCP to be like mastoid cells. PCP can lead to clinical symptoms due to alterations in posture and functional limitations in neck movements. Thus awareness of this process, its topographical relations and its attendant problems is of importance to clinicians, radiologists, surgeons and chiropractors. In symptomatic cases surgical resection of this process can be attempted to relieve the symptoms. The craniovertebral junction constitutes a unique part of the somite-derived axial skeleton; the lowest part of the basioccipital component including this process develops from occipital sclerotomes. Developmental variations in this region can resemble deformities.