Anatomical partition of the clival region and adjacent structures via extended endoscopic endonasal approach

• The clivus was divided into 6 regions with the internal carotid artery (ICA).
• The ICA is related to ventral side of clivus and its surrounding structure.
• The ICA can be used as the basis of anatomic division through the anterior approach.

ObjectivesTo explore the anatomy of the ventral clivus and adjacent structure in the endoscopic surgery through the anterior approach, particularly in accurate locating lesions in transnasal endoscopic surgery.Patients and methodsA total of 9 formalin-fixed adult cadaver heads were injected with red and blue latex to observe the arteries and veins, respectively. The relationships between various parts of internal carotid artery (ICA) and anatomic structures of clivus were investigated, followed by the measurement of the posterior pharyngeal wall, anterior wall and posterior wall of clivus, cerebral dura mater, subdural space and adjacent regions to determine their correlations, as well as the clivus and adjacent structures.ResultsThe clivus structure was divided into the bone segment, the ICA segment and subdural segment for anatomic division according to the anatomic landmarks in the anatomic process. The clivus can be classified in a shape of ‘’ with the ICA, including the middle superior region, middle inferior region, bilateral lateral superior and lateral inferior regions.ConclusionThe ICA is closely related to the ventral clivus and adjacent structure, which can be used as the basis of anatomic division via anterior approach.