Morphology of the olfactory fossa – A new look

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 (1–3mm) was 23.44%, type II (4–7mm) – 70.83% and type III (8–16mm) – 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.