Patterns of the spheno – ethmoidal and fronto – ethmoidal sutures in the anterior cranial fossa in Thais.

ABSTRACT

Ninety – six dry, adult Thai skulls, 50 males and 46 females, were studied for patterns of sphenoethmoidal and fronto – ethmoidal sutures. In all of the skulls, the posterior border of the cribriform plates of ethmoid bones articulated with the anterior margin of ethmoidal spine and the posterior border of orbital plate of the frontal bone articulated with the anterior border of the lesser wing of the sphenoid bone. The distribution of the patterns was divided into 5 types according to the shape of the ethmoidal spine and the various forms of suture. In type I (29%), rthmoidal spine was triangular in shape and projected forward in the medium from the jugum sphenoidale to articulate with the back of back of the cribrifrom plate. In type II (25%), the area of the sphenoid was reduced by the right and left retro – ethmoidal processes of the frontal so that ethmoidal spine had a quadrilateral extension joining it to the jugum sphenoidale. In type III (29%), the sphenoidal area was further reduced so that the ethmoidal spine appeared to have developed a constricted neck. In type IV (14%), the ethmoidal spine was triangular in shape but did not take a part of jugum sphenoidale. It articulated along a transverse line directly with the jugum sphenoidale. Finally, in type V (3%), the ethmoidal spine did not articulate with the jugum sphenoidale because of the meeting retro – ethmoidal processes of the frontal bone. The distribution of the various types was not significally different in sex but significally different in race.