Embryology and Anatomy of the Sella and Parasellar Region

The sellar/parasellar region can have a multitude of pathologies leading to an often-broad differential diagnosis. This chapter will first review the important anatomy of the sella/parasellar region including both the bony anatomy and meninges of the sellar/parasellar regions. The important bony anatomical landmarks as well as the contents of the sella/parasellar regions will be included including the normal size, signal intensity and enhancement pattern of the pituitary gland, as well as the subjacent cavernous sinus. This region is very anatomically complex and can have a vast array of pathologies occurring here—congenital, infectious/inflammatory, benign, and neoplastic lesions. Imaging technique will briefly be discussed prior to delving into several of the more important etiologies occurring within this region—intrasellar, parasellar, and infundibular. Each example will illustrate both the important clinical information and imaging characteristics to help the reader distinguish between various pathologies and potentially helping the reader to narrow down the differential diagnosis of the sellar/parasellar region.