Surgical Importance of the Morphometry of the Anterior and Middle Cranial Fossae

Abstract

The present study was undertaken to determine the morphometric relationships between specific aspects of the cranial anterior and middle fossae because of their importance as landmarks in surgical approaches to the skull base. Bilateral and midline measurements were made between specific anatomic landmarks. The mean midline anteroposterior width of the lesser wing of the sphenoid and distance from the crista galli to the tuberculum sellae were 20 and 35.6 mm, respectively. Significant differences (P<0.05) between right and left sides measurements were observed for the length of the lesser wing of the sphenoid (46.6 mm right, 44.8 mm left), the distance between the crista galli and the lateral tip of the sphenoid (53.1 mm right, 51.1 mm left), and the angle subtended by the distance between the tuberculum sellae and the internal acoustic meatus (57.3 degrees right, 55.1 degrees left). No other differences in bilateral measurements were observed. The mean length of the lateral tip was 2.6 mm; the mean distance between the crista galli and the midpoint of the lesser wing was 31.5 mm; the mean distances between the foramen ovale and the anterior clinoid process and the midpoint of the lesser wing were 23.0 and 32.1 mm, respectively. The mean distances between the internal acoustic meatus and the lateral tip and the tuberculum sellae were 55.9 and 49.5 mm, respectively. The mean angle between the midline and the lateral tip measured at the crista galli was 59.10 degree. The mean angle subtended by the distance from the crista galli to the tuberculum sellae at the lateral tip was 43.30 degree. A sound knowledge and understanding of the relationships between morphometric measurements and the relevant anatomic structures in relation to the sphenoid may be of use to neurosurgeons.