Sphenoidal defects--a possible cause of cerebrospinal fluid rhinorrhoea.

In a study of 138 adult sphenoidal bones, 27 defects which could cause cerebrospinal fluid rhinorrhoea were found. Fourteen of these defects were situated at the site of the superior opening of the transient lateral craniopharyngeal canal. The remaining 13 defects were situated along the pathway of the internal carotid artery. The gross and microscopic appearance of the defects is consistent with their production by a process of `focal atrophy' caused by the pressure of the internal carotid artery and other adjacent structures.