%0 Journal Article
%T Occipital Emissary Foramina in South Indian Modern Human Skulls
%A Suruchi Singhal
%A Roopa Ravindranath
%J ISRN Anatomy
%D 2013
%R 10.5402/2013/727489
%X An occipital emissary foramen has been traditionally described as a foramen present in the squamous part of the occipital bone at the occipital protuberance transmitting a vein that connects the confluence of sinuses with the occipital vein. The present study was done on 221 South Indian adult modern human skulls of unknown sex in the Department of Anatomy, St JohnĄ¯s Medical College, Bangalore, India. The foramen was observed in 21/221 (9.50%) skulls, 6/21 (28.57%) to the right of, 10/21 (47.61%) to the left of, and 2/21 (9.52%) on the External Occipital Crest. It was seen more often near the posterior margin of foramen magnum rather than at the External Occipital Protuberance as has been traditionally described. A new finding is that bilateral foramina were observed in 3 skulls (14.28%). The incidence was higher than seen in other Indian population. Since it is present near the foramen magnum in most cases, knowledge of the number and position of the foramen is important for suboccipital craniotomies. The extensive connections of the veins with cranial venous sinuses may lead to intracranial infections and vice versa. 1. Introduction Emissary veins traverse emissary foramina of the skull and connect venous sinuses to extracranial veins. Although they are valveless and blood may flow in both directions, flow is usually away from the brain. In ordinary usage, emissary foramina are restricted to mastoid, parietal, condyloid, and the foramen of Vesalius. An occipital emissary foramen has been traditionally described as a solitary foramen occasionally present in the squamous part of the occipital bone at the occipital protuberance [1]. It transmits the occipital emissary vein that connects the confluence of sinuses with the occipital vein. The emissary vein may also receive the occipital diploic vein [2, 3]. This traditional view has now been challenged as the foramen has in the recent studies been found more often near the foramen magnum than the External Occipital Protuberance [4¨C6]. The present study was done to ascertain the incidence of the foramen in unsexed adult modern human skulls of South Indian origin. The position of the foramen was also determined as a comparison of the study with the traditional and existing literature was done. The findings of the study were then correlated to possible clinical manifestations that may arise due to the position and number of emissary foramina if seen on the skull. 2. Materials and Method The study was done on 221 South Indian adult modern human skulls of unknown sex in the Department of Anatomy, St JohnĄ¯s
%U http://www.hindawi.com/journals/isrn.anatomy/2013/727489/