VARIABLE FORAMEN OF HYRTL OF THE HUMAN SKULL

Variable foramen on the grater wing of sphenoid bone, which is simultaneously complementary opening between the orbit and middle cranial fossa. It can be find, unilaterally or bilaterally, lateral to the superior orbital fissure, below posterior margin of the lesser wings of the sphenoid bone. The aim of this work was, to establish, the incidence of this variable foramen between orbit and middle cranial fossa, and its morphology characteristics in the cases where it exist, on the small series of human skull. Material was 30 human skulls (15 dried and 15 non-dried) from collection of Department of anatomy and Department of forensic medicine of Medical faculty in Nish. The name of the openig was given as suggestion of the autor in this work: the opening on the grater wing of the sphenoid bone was named as foramen of Hyrtl or H-foramen (foramen H); the groove on the grater wing of the sphenoid bone, which extends from this opening, was marked as meningolacrimal groove. The presence of this foramen was established in 13 (43,3%) cases, and in 11 (36,7%) cases the opening was unilateral (5 on the left and 6 on the right side). The foramen was bilateral in 2 (6,7%) cases. It was observed that the opening was round or rarely eliptical. The foramen was obvious on the inner surface of the grater wing of the sphenoid bone, as well as on the upper half of the lateral wall of the orbit, with variable distance from the lateral end of the superior orbital fissure. Variable H-foramen was detected in 43,3% of the cases, mostly unilaterally on the grater wing of the sphenoid bone. Simultaneous existence of the H-foramen and meningolacrimal groove, indirectly point to the later obliteration of the primitive stapedial artery on the same side. Orbital groove existence do not coincidence with H-foramen existence. Dependence between the size of the H-foramen diameter and the distance from the foramen spinosum and lateral end of the superior orbital fissure was not established.