[Changes in the sphenoid bone in the upper third of the carotid groove]

The article discusses the changes of the bone plate of the sphenoid bone in the upper third of the carotid groove; the plate separates the siphon of the internal carotid artery from the cavity of the sphenoid sinus. Both carotid grooves were examined on blocks removed from the base of the skull of 65 cadavers and on 45 macerated skulls. Two types of bone changes were found in the upper third of the carotid groove, namely, osteoporosis and perforating defects. Osteoporosis was revealed in 50 grooves and defects only in the upper third in 45 grooves. Osteoporosis and defects were encountered about five times more frequently between the ages of 41 and 60 than till the age of 40 and 10 times more frequently after the age of 60. The same relations were found when osteoporosis was combined with a defect. These bone defects are an anatomical precondition for profuse nasal bleeding because the wall of the internal carotid artery ruptures during a craniocerebral trauma and blood flows freely from it into the sphenoid sinus and then into the nasopharynx.