Original Investigations Turkish Neurosurgery 2011, Vol: 21, No: 1, 36-38 36 Occipital Emissary Foramina in Human Skulls: An Anatomical Investigation with Reference to Surgical Anatomy of Emissary Veins İnsan Kafatası İçinde Oksipital Bölgede Yer Alan Delikler: Delici Venlerin Cerrahi Anatomisi: Referans ile Anatomik Bir Soruşturma B.V. MURLIMANJU, Latha V. PRABHU, Mangala M. PAI, Mir JAFFAR, Vasudha V. SARALAYA, Mamatha TONSE, Prameela M.D. Manipal University, Department of Anatomy, Kasturba Medical College, Mangalore, India is paper has been presented at the 12th state-level conference of Karnataka Chapter of Anatomists which was held at Kolar, INDIA on 6th to 8th August 2010. Correspondence address: B.V. Murlimanju / E-mail: flutesnowmm@gmail.com ABSTRACT AIM: The objectives were to find the incidence and topography of the occipital emissary foramina in skulls of South Indian Region. MATERIAL and METHODS: In the present study, 78 dried adult human skulls were examined. They were analyzed for the gross incidence and position of the occipital emissary foramen. The observations were made in the squamous part of the occipital bone from the posterior margin of the foramen magnum to the external occipital protuberance. RESULTS: From our observations, the occipital emissary foramen was present in 11 (14.1%) skulls. Left sided foramen was observed in 5 cases (6.4%), right-sided foramen in 4 (5.1%) and the median foramen was seen in 2 (2.6%) of the cases. CONCLUSION: The occipital emissary vein is present in a small percentage (14.1%) of cases. It was also demonstrated that its location is variable as to left, right or midline. Its location was closer to the foramen magnum than to the external occipital protuberance in all the specimens. The morphology of this subject is important to the neurosurgeons and plastic surgeons. The knowledge is of importance in suboccipital craniotomies as this foramen transmits the occipital emissary vein and will keep awareness among the surgeons to avoid the excessive bleeding. KEYWORDS: Emissary vein, Foramen, Foramina, Neurosurgery, Skull, Suboccipital ÖZ AMAÇ: Güney Hindistan bölgesinde yaşamış insanların oksipital kemiklerindeki venöz deliklerin yerleşiminin ve sıklığının belirlenmesi. YÖNTEM ve GEREÇ: Bu çalışmada, 78 erişkin insan kafatası incelendi. Oksipital kemiğin skamöz parçasının foramen magnum ile eksternal oksipital kabarıklık arasında kalan bölümü oksipital emisser delik açısından incelendi. BULGULAR: İncelenen kafataslarından 11’inde (%14,1) emiser delik bulundu. Beş kafatasında (%6,4) emisser delik solda, 4 kafatasında (%5,1) sağda, 2 kafatasında (%2,6) ise orta hatta izlendi. SONUÇ: İncelenen kafataslarının % 14.1’inde oksipital emisser ven deliği bulundu. Bulunan bu delikler sabit bir yerde değil sağ, sol ve orta hatta yerleşim gösteriyordu. Emiser oksipital deliğin farklı yerleşiminin bilinmesi plastik cerrahlar ve beyin cerrahları açısından özellikle önemlidir; çünkü bu delikten geçen venin hasarlanması durumunda önemli ölçüde kan kaybedilmektedir. ANAHTAR SÖZCÜKLER: Emisser ven, Foramen, Foramenler, Nöroşirürji, Kafatası, Suboksipital INTRODUCTION It is known that the morphological diferences exist between the skulls of diferent races (9). Many anatomical studies have focused on the diferent skull foramina including various emissary foramina and detailed descriptions of the occipital emissary foramina are scarce in the literature. The emissary foramina transmit the emissary veins which connect intracranial venous sinuses with the extracranial veins (8). They act as the outlet veins of the neurocranium and drain the venous blood from cephalic structures. Though they are valveless and blood may fow in both the directions, the fow is usually away from the brain. Under normal circumstances, blood fow through these veins is slow. However, in cases of raised intracranial tension they become an important source of blood drainage (6). The knowledge of these foramina, especially occipital emissary foramina is important because of the recent advances in neurointerventional and neurosurgical techniques (4). The occipital sinus and suboccipital venous Received: 14.08.2010 / Accepted: 24.08.2010