The intracranial course of the cranial nerves is important for the diagnosis of various intracranial lesions, such as brain tumors and intracranial aneurysms. Dysfunction of one or more cranial nerves indicates compression or stimulation due to injury. For example, an acoustic schwannoma may initially cause distubance in the hearing, but with additional tumor growth it may involve other cranial nerves and the patient may present pain similar to trigeminal neuralgia when the tumor involves the trigeminal nerve or diplopia due to the involvement of the abducent nerve similarly facial paralysis compression of the facial nerve These findings together with the cerebellar signs will suggest the diagnosis of a CP Angle SOL. A patient with ptosis may have a posterior communicating artery aneurysm that compresses the ocular motor nerve during its intracranial course. Facial pain in the distribution of one or all divisions of the trigeminal
nerve suggests the stimulation of the trigeminal nerve roots by a nearby vessel...........