Original Article Morphology of the olfactory fossa e A new look Tony George Jacob a, *, J.M. Kaul b a Assistant Professor, Department of Anatomy, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi 110029, India b Director Professor, Department of Anatomy, Maulana Azad Medical College, Bahadur Shah Zafar Marg, New Delhi 110029, India article info Article history: Received 22 December 2013 Accepted 10 April 2014 Keywords: Ethmoid Endoscopy Cribriform plate Fovea ethmoidalis Morphometry abstract Introduction: The olfactory fossa is a depression in the anterior cranial cavity whose floor is the cribriform plate of the ethmoid bone. This delicate bony plate separates the anterior cranial fossa from the nasal cavity. Methods: We studied the morphology of the olfactory fossa in 32 dry skulls, derived from North India, of undetermined sex, using a hydroxyphilicsiloxane based gel. Molds of the olfactory fossa and adjacent cranial fossa were made and measurements of length, width, depth and angle of embankment (angle between the lateral wall of the olfactory fossa and the medial part of the anterior cranial fossa) were done on them and their coronal sections. Results: The average length of the olfactory fossa was 2.11 cm. The average width was 0.39 cm and the mean angle of embankment was 130.5  . According to the measured depth, the incidence of Keros’ type I (1e3mm) was 23.44%, type II (4e7mm) e 70.83% and type III (8 e16mm) e 5.73%. Type III was more frequent on the left side. The fossa in north India is deeper in the middle than its anterior and posterior ends. It had a narrow anterior and broad posterior end (54.69%). There were no overall significant differences between the right and left side for the various morphometric parameters. Discussion: This study provides baseline morphometric data of the olfactory fossa in the North Indian population and this knowledge may help the radiologists to analyze scans of this region and minimize complications associated with surgeries in this delicate area. Copyright ª 2014, Anatomical Society of India. Published by Reed Elsevier India Pvt. Ltd. All rights reserved. 1. Introduction Functional endoscopic sinus surgery (FESS) has become a common modality of treatment for disorders of the nose and paranasal sinuses. Prior knowledge of the anatomy of the paranasal sinuses, anterior skull base and olfactory zone is necessary for good results. 1,2 The ethmoid is a complex and delicate bone that lies in the midline of the facial skeleton. It is the key bone in FESS. 3 It consists of a midline perpendicular plate and crista galli and two lateral labyrinths of air cells connected to each other * Corresponding author. E-mail address: tonygeorgejacob@gmail.com (T.G. Jacob). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/jasi journal of the anatomical society of india xxx (2014) 1 e6 Please cite this article in press as: Jacob TG, Kaul JM, Morphology of the olfactory fossa e A new look, Journal of the Anatomical Society of India (2014), http://dx.doi.org/10.1016/j.jasi.2014.04.006 http://dx.doi.org/10.1016/j.jasi.2014.04.006 0003-2778/Copyright ª 2014, Anatomical Society of India. Published by Reed Elsevier India Pvt. Ltd. All rights reserved.