Floor of the Anterior Cranial Fossa

Abstract

The floor of the anterior cranial fossa is the part of the interior skull base which supports most of the orbital frontal lobe of the cerebrum, olfactory bulb, and olfactory tract. The posterior part of the floor overhangs the middle fossa somewhat, especially where it relates to the medial portion of the frontal lobe (see Lang 1979). The orbital parts of the frontal bone form the greater portion of the floor of the anterior fossa. Between them is the ethmoid bone with its cribriform plate. The posterior floor region is completed by the lesser wings of the sphenoid, which delimit the optic canals, and by the planum sphenoidale. The lesser wing extends laterally for a variable distance and becomes continuous with the sylvian crest formed by the frontal bone below the greater sphenoid wing. In 30%–60% of the population this area contains a branch of the meningeal artery, its accompanying veins, and/or the meningeal sinus (e.g., Lang and Tisch-Rottensteiner 1976). The anatomy of this portion of the floor is an important surgical concern in patients with frontobasal fractures, olfactory groove neoplasms, and in surgical approaches to the pituitary region and optic canal.