Medullary Groove

Medullary groove

The medullary groove is a depression on the upper edge of the bony plate of the ethmoid bone, which borders the orbit on the lateral side (Fig.a). Permeates the entire perimeter of the plate. It begins behind the internal auditory canal and ends below at the junction of the posterior part of the facial surface of the mastoid process into the upper surface. There is no groove at the top, which is an important diagnostic sign, since when fractures occur, its torn fragments usually do not penetrate into the facial bone. If there is no groove, we can assume that there is no fracture. The width of the groove inlet is 3-6 mm, the length from the rear edge of the front plate to the lower end is up to 25 mm.