The floor of the cranial cavity that separates the brain from other facial structures known as s kull base or cranial base. Skull base or cranial base consists of five bones ethmoid, paired frontal, sphenoid, paired temporal bones and occipital bone. It has two surfaces: endocranial(superior) and exocranial (inferior) surface. The endocranial surface faces towards the brain and the exocranial surface towards the nose, sinus and infratemporal fossa. The cranial cavity is divided into anterior, middle and posterior cranial fossa so the skull base is divided into anterior, middle and posterior skull base. The skull base is also divided into central and lateral parts by two lines drawn along the medial pterygoid plate. Anatomically, this region is complex and poses surgical challenges for surgeons in negotiating this area (Fig. 17.1).