Fructure base of the skull is very common when the skull is subjected to a deforming force,eg. crushing as in traffic accidents or by a blunt object as seen below.
A front to back compression as in cases of blunt impacts or falls on the forehead or back of the head result in a longitudinal pattern of fructure base of the skull. A side to side compression force result in transverse pattern of fructure base of the skull.
Forces transmitted to the basi-occiput through the vertebral column as in cases of heavy falls on the buttocks or heavy blows to the vertex result in fructure of the basi-occiput around the foramen magnum producing a ring shaped fracture.
Fructure base of the skull should be suspected if there is ecchymosis of the upper and lower eye lids (raccoon eye),ecchymosis around mastoid process and/or bleeding from ears and nostrils.