Functional Anatomy for Transsphenoidal Approach

Taking advantage of the nasal cavities as a natural corridor, the endoscopic endonasal approach represents nowadays the gold standard for the management of several lesions at the skull base. From the so-called standard approach to the sellar region, adopted for the treatment of pituitary adenomas, the extended variations of the endonasal endoscopic approach have provided the neurosurgeons the possibility of reaching the entire midline skull base, from anterior to posterior cranial fossae, and challenging neurovascular spaces like pterygopalatine fossa, opto-carotid region, and cavernous sinus. Due to the unfamiliar anatomy of the nasal cavity and the different perspective given by the endoscopic view, a deep knowledge of the anatomy is mandatory to avoid loss of orientation and perform the surgical procedure in the safest way. The aim of this chapter was to remark the most important anatomic landmarks which will be encountered in each step of the standard endonasal transsphenoidal approach.