VARIANTS OF MASTOID AND OCCIPITAL EMISSARY FORAMENS AND THEIR CLINICAL CORRELATION

Abstract

Purpose: Emissary foramens in the skull and emissary veins (EV), respectively, have been known for a long time, but their importance is often disregarded. In the present study, we introduce variants of occipital emissary foramens (OEF) unilaterally located on the left, close to оccipital condylе in a formation of three apertures that open together in a sinus near clivus. Material/Methods: Corpses of 30 dеad people were dissected in the Department of Anatomy, and standard techniques for soft tissue separation or maceration of the skull were used. After the removal of the calvaria, fixed bones of the skull were disarticulated. Foramens were cleaned using a double-ended probe, and depth and diameter measurements were performed using an atomical caliper. Results: We found variants of mastoid emissary foramens (MEF) situated into two groups, each of a couple of foramens. Their clinical significance is discussed, compared with existing experience and analysis of their phylogeny and embryogenesis. Conclusion: We introduce OEF and MEF to be important markers for detection of dural venous sinuses (DVS). The latter, together with EV, provide an important mechanism for decreasing intracranial pressure. This happens due to the absence of a valve apparatus in the veins of the brain, and the lack, or small amount, of muscle tissue. There is a possibility of existing varicose veins, such as those caused by arterio-venous fistulas and the pathology associated with it. We suggest the application of EV in imaging as an important study before surgery by lateral and transcondylar approach to the anterior foramen magnum.