R. NICKBRYANMDPATRICIA A.HUDGINSMD
The petrous apex together with the ventral part of the middle cranial fossa can be involved in congenital, infectious, inflammatory, and neoplastic processes. A lesion may remain undetected for a long time because patients often complain of indistinct symptoms that may delay diagnosis. Clinical presentations can range from otitis media, trigeminal paresthesia or numbness, and headache or eye pain due to stretching of the dura. Tinnitus, vertigo, hearing loss, ophthalmoplegia, and facial paralysis can also occur. Because direct examination is not possible, careful attention to the subtle symptoms is extremely important. The greater petrosal nerve carries parasympathetic fibers of the facial nerve. It leaves the facial nerve at the geniculate ganglion via the hiatus of the greater petrosal nerve, which is found in the middle cranial fossa. The greater petrosal nerve passes forward across the foramen lacerum, where it is joined by the deep petrosal nerve (sympathetic from superior cervical ganglion). Together, these 2 nerves supply the lacrimal gland and the mucus-secreting glands of the nasal and oral cavities. Although the carotid artery is often compressed by lesions of the petrous apex, vascular symptoms are uncommon, except in the presence of an aneurysm. These lesions, especially benign cystic ones, frequently reach a significant size, with marked bony erosion, before diagnosis is made; they also pose several diagnostic and therapeutic dilemmas. The relative inaccessibility of this location, in association with surrounding bony, neural, and vascular structures, often precludes traditional diagnostic techniques such as a simple biopsy.1
Radiology Quiz Case 1: Diagnosis. Arch Otolaryngol Head Neck Surg. 2006;132(1):104. doi:10.1001/archotol.132.1.104
Coronavirus Resource Center
Customize your JAMA Network experience by selecting one or more topics from the list below.