Anatomical variations and morphometric study of the optic strut and the anterior clinoid process

Abstract

Th e optic strut and the anterior clinoid process represent bony structures that are closely related to anatomically and clinically signifi cant elements such as the cavernous sinus, the internal carotid artery, the optic nerve and the pituitary gland. Th e objective of our study was to quantify dimensions of the optic strut and anterior clinoid process, and to determine variations in positions and forms of these structures. A descriptive anatomical study was performed on  dry human skulls. We analyzed dimensions and variations in position of the optic strut, dimensions of the anterior clinoid process as well as the incidence and forms of the caroticoclinoid foramen. Th e average thickness of the optic strut on skulls belonging to males was  mm and . mm on those belonging to females. Th e optic strut was most commonly attached to the anterior two fi fths on the lower side of the anterior clinoid process. On the male skulls the average width of the anterior clinoid process was . mm (right) and . mm (left). Its length was . and . mm. On female skulls the average width of the process was . mm (right) and . mm (left), while the length measured . mm on the right and . mm on the opposite side. In our sample, a complete caroticoclinoid foramen appeared in ., a contact form in .. At last, an incomplete form of the foramen was observed in .. Th e anatomic variations of the investigated structures must be considered during the approaches to the cavernous sinus and neurovascular elements of the sellar region.

The pneumatisation of anterior clinoid process is not associated with any predictors that might be recognised preoperatively

“…Other authors did not find any influence of gender and side of ACP on the increased incidence of pneumatised processes either [1,14]. However, our study did confirm the well-known principle that scrupulous CT imaging assessment should precede ACP removal in every case [1,10]. Patient age has not yet been investigated and compared between pneumatised and osseous ACPs.…”

“…the preoperative evaluation of ACP facilitates safer high--speed drilling and is recommended by practitioners [1,10]. Intraoperative neural or vascular damage occurs more often in pneumatised ACP than in osseous examples.…”

“…The process projects posteriorly and medially in the middle cranial fossa and constitutes a boundary of the caroticoclinoid foramen if the ACP is merged with the top of the medial clinoid process [10]. The ACP is closely related to many vital neurovascular structures, including the internal carotid artery (ICA) adjacent to the medial and posterior aspect of the ACP [8,22].…”

“…Thus, attention to detail with regards to complication avoidance is up to date. Radiographic evaluation of air cell infiltrate into the ACP in all cases, including any of the previously mentioned indications, is recommended if bony destruction in the middle cranial fossa is considered preoperatively [10,14,22]. However, in emergent situations, such as patients with a ruptured aneurysm, the preoperative assessment of pneumatisation is occasionally abandoned.…”

The erroneous eponym of the carotico-clinoid foramen of Henle: attribution is due to Alexander Monro (primus)

“…[1,[4][5][6][7][8][9][10][11][12][13][14][15][16] However, Henle was not the first to describe the CCF.…”