Incomplete Bilateral Caroticoclinoid Foramina in a Dry Human Skull: A Rare Case Reported With Clinicoanatomical Relevance.

Caroticoclinoid foramen (CCF) is an inconsistent structure formed due to the ossification of either the caroticoclinoid ligament or a dural fold extending between the anterior and middle clinoid processes of the sphenoid bone during development. For the surgical procedure of anterior clinoidectomy in case of a paraclinoid aneurysm of the internal carotid artery (ICA), the presence of a bony CCF may lead to heavy haemorrhage and other complications like CSF rhinorrhea, injury of adjacent structures like the optic nerve and oculomotor nerve. We present a case of incomplete bilateral caroticoclinoid foramina in a dry female human skull of unknown age, with no structural deformity. The diameter of the incomplete CCF on the right side measured 3.9 mm, while that of the left side was 4 mm. The interspicular distance between the opposing bony spurs was estimated to be 1.1 mm on the right side and 0.8 mm on the left side. The ICA, while traversing through the cavernous sinus, passes medial to the anterior clinoid process. Therefore, neurosurgeries approaching the anterior clinoid process are likely to damage the ICA and surrounding intracranial structures if CCF is present. This case is interesting due to the unusual pattern with regard to its bilaterality, not reported earlier, and its significance to the knowledge of the skull-base anatomy and implications for neurosurgical anatomy.