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

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The 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.


The 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.


A 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.


The 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.

ABBREVIATIONS CCF = caroticoclinoid foramen; ICA = internal carotid artery.

Article Information

Correspondence Matthew J. Zdilla: West Liberty University, West Liberty, WV.

INCLUDE WHEN CITING Published online December 14, 2018; DOI: 10.3171/2018.9.PEDS18481.

Disclosures The author reports no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.



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    Superior view of a sphenoid bone from an 8-month-old black female fetus. A complete CCF is found on the left, and a partial CCF, formed by a cornuate bony projection from the anterior clinoid process, is found on the right. Figure is available in color online only.

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    Superior view of the left- and right-sided orbitosphenoid bones from a 6-month-old white male fetus. Near-complete CCFs are seen bilaterally. The posterior and posterolateral boundaries of the near-complete foramina are formed by bony extensions from the anterior clinoid processes found bilaterally. Figure is available in color online only.

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    Superior view of the sphenoid bone from a newborn white male infant. Partial CCFs are seen bilaterally. In this case, extensions from the anterior clinoid processes are forming the posterolateral boundaries of the incomplete foramina, and bony projections arising from the presphenoid region of the sphenoid (i.e., the middle clinoid processes) are extending posterolaterally to form the posteromedial boundaries of the incomplete foramina. The bony processes arising from the middle clinoid processes are asymmetrical—the left-sided projection is marked, while the right-sided projection is relatively small. Figure is available in color online only.

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    Heat map relating the relative frequency (expressed as a percentage) of CCF types to age in fetal and infant populations.



Azeredo RALiberti EAWatanabe IS: [Anatomical variations of the clinoid process of the human sphenoid bone.] Arq Cent Estud Curso Odontol 25-26:9111988 (Portuguese)


Bonneville JFDietemann JL: Embryology of the sellar region in Bonneville JFDietemann JL (eds): Radiology of The Sella Turcica. Berlin: Springer1981


Das SSuri RKapur V: Ossification of caroticoclinoid ligament and its clinical importance in skull-based surgery. Sao Paulo Med J 125:3513532007


Ertürk MKayalioğlu GGovsa F: Anatomy of the clinoidal region with special emphasis on the caroticoclinoid foramen and interclinoid osseous bridge in a recent Turkish population. Neurosurg Rev 27:22262004


Gupta NRay BGhosh S: A study on anterior clinoid process and optic strut with emphasis on variations of caroticoclinoid foramen. Nepal Med Coll J 7:1411442005


Hochstetter F: Über die taeniainterclinoidea, di commissuraalicochlearis und die cartilago supracochlearis des menschlichen primordialkraniums. Gegenbaurs Morphol Jahrb 84:2202431940


Inoue TRhoton AL JrTheele DBarry ME: Surgical approaches to the cavernous sinus: a microsurgical study. Neurosurgery 26:9039321990


Jha SSingh SBansal RChauhan PShah MPShah A: Nonmetric analysis of caroticoclinoid foramen in foothills of Himalayas: its clinicoanatomic perspective. Morphologie 101:47512017


Kapur EMehić A: Anatomical variations and morphometric study of the optic strut and the anterior clinoid process. Bosn J Basic Med Sci 12:88932012


Kawakubo YDodo YKuraoka A: Two hyperostotic non-metric traits, caroticoclinoid foramen and pterygospinous foramen, which appear at an early developmental stage in the human cranium. Anthropol Sci 121:1231302013


Keyes JEL: Observation on four thousand optic foramina in human skulls of known origin. Arch Ophthalmol 13:5385681935


Kier EL: Embryology of the normal optic canal and its anomalies. An anatomic and roentgenographic study. Invest Radiol 1:3463621966


Kier EL: Fetal skull in Newton THPotts DG (eds): Radiology of the Skull and Brain. St Louis: Mosby1971


Kodama G: Developmental studies on the presphenoid in the human sphenoid bone. Okajimas Folia Anat Jpn 41:1591771965


Lang J: Structure and postnatal organization of heretofore uninvestigated and infrequent ossifications of the sella turcica region. Acta Anat (Basel) 99:1211391977


Lee HYChung IHChoi BYLee KS: Anterior clinoid process and optic strut in Koreans. Yonsei Med J 38:1511541997


McMurrich JP: The Development of the Human Body: A Manual of Human Embryologyed 3. Philadelphia: P Blakiston’s Son & Co1907 p 183


Monro A: The Anatomy of the Humane Bones. Edinburgh: Thomas Ruddiman1726 p 122


Nemzek WRBrodie HAHecht STChong BWBabcook CJSeibert JA: MR, CT, and plain film imaging of the developing skull base in fetal specimens. AJNR Am J Neuroradiol 21:169917062000


Ozdoğmuş OSaka ETulay CGürdal EUzün ICavdar S: The anatomy of the carotico-clinoid foramen and its relation with the internal carotid artery. Surg Radiol Anat 25:2412462003


Peris-Celda MKucukyuruk BMonroy-Sosa AFunaki TValentine RRhoton AL Jr: The recesses of the sellar wall of the sphenoid sinus and their intracranial relationships. Neurosurgery 73 (2 Suppl Operative):ons117ons1312013


Sharma ARieth GETanenbaum JEWilliams JSOta NChakravarthi S: A morphometric survey of the parasellar region in more than 2700 skulls: emphasis on the middle clinoid process variants and implications in endoscopic and microsurgical approaches. J Neurosurg 129:60702018


Souza ADAnkolekar VHNayak NHosapatna MSouza AS: Morphometric study of anterior clinoid process and optic strut and the ossification of carotico-clinoid ligament with their clinical importance. J Clin Diagn Res 10:AC05AC072016


Standring S (ed): Gray’s Anatomy: The Anatomical Basis of Clinical Practiceed 40. New York: Churchill-Livingstone/Elsevier2008 p 530


Zdilla MJ: The erroneous eponym of the carotico-clinoid foramen of Henle: attribution is due to Alexander Monro (primus). Anatomy 11:1041062017


Zdilla MJCyrus LMLambert HW: Carotico-clinoid foramina and a double optic canal: a case report with neurosurgical implications. Surg Neurol Int 6:132015




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