The caroticoclinoid foramen in fetal and infantile orbitosphenoid, presphenoid, and sphenoid bones: developmental and neurosurgical considerations.

OBJECTIVEThe presence of a caroticoclinoid foramen may increase the likelihood of adverse neurosurgical events. Despite the clinical importance of the caroticoclinoid foramen, its study has been mostly limited to adult populations. Therefore, the object of this study was to describe the prevalence, morphology, and development of the caroticoclinoid foramen among varied sexes and races in early life.METHODSThe study analyzed caroticoclinoid foramina in dry orbitosphenoid, presphenoid, and sphenoid bones from a population of 101 fetal and infantile crania of varied sex and race.RESULTSA caroticoclinoid foramen, whether complete, near complete, or partial, was found in 36 of 199 sides (18.1%). Of the 98 crania with bilaterally intact sides, 21 (21.4%) had the presence of at least one caroticoclinoid foramen. Caroticoclinoid foramina were found unilaterally and bilaterally, in both female and male crania (9/41, 22.0%; 12/57, 21.1%, respectively) and, likewise, in crania of both black and white races (9/54, 16.7%; 12/44, 27.3%, respectively). Caroticoclinoid foramina were formed from cornuate bony projections from the anterior clinoid process, middle clinoid process, or both anterior and middle clinoid processes. Caroticoclinoid foramina were also found in isolated orbitosphenoid bones from individuals as young as 4 months' fetal age.CONCLUSIONSThe caroticoclinoid foramen occurs in approximately one of every 5 sides and in one in every 5 individuals of perinatal age and should, therefore, be considered a common finding in both fetuses and infants. It is common in both females and males as well as in both black and white races, alike. Furthermore, the caroticoclinoid foramen can be found in individuals as young as 4 months of fetal age. Failure to anticipate the presence of a caroticoclinoid foramen will place important neurovascular structures, including the internal carotid artery, at risk of injury. Neurosurgeons should, therefore, anticipate the caroticoclinoid foramen even in their youngest patients.