Temporal bone fracture

Temporal bone fracture

A temporal bone fracture is a break that occurs in the temporal bone. It occurs after head trauma, either penetrating but mostly blunt trauma. The temporal bone is one of the major bones of the skull. Situated at the side of the skull it hosts the ear structures of hearing and balance but also the major blood vessels that supply and drain blood from the brain. Furthermore it hosts the facial nerve which supply motion to the facial muscles of expression, secretory function to the tear gland and other glands and relay taste from the tongue.

Transvers temporal bone fracture
Right temporal bone fracture. Yellow line and black arrows demonstrate a transvers fracture of the temporal bone. The right line demonstrates where a longitudinal fracture would be. Cochlea(C).

The inner ear structures of the cochlea and vestibular apparatus are situated in very dense hard bone called the otic capsule. The surrounding part of the temporal bone is a different but more common form of bone called cancelous bone. The otic capsule is formed at birth and stays the same size throughout life. It never growths. When fractured it never heals with new bone. The fracture lines are replaced by soft scar tissue.

Depending on the direction of the force of the injury different types of fractures can occur. It can either be in the length of the bone (longitudinal) or across the width of the bone (transverse). With severe trauma a combination of fractures are possible.

The consequences of a temporal bone fracture are hearing loss, tinnitus, vertigo, dizziness, balance problems, facial nerve injury, tear of the tympanic membrane (ear drum) and discharge from the ear. With a skull base fracture the watery discharge is usually cerebrospinal fluid from the brain.

An important aspect of temporal bone fractures is that it is often overlooked in the presence of more serious head and brain injuries after trauma. Often a patient is in a coma and cannot complain of the typical symptoms. Even a facial nerve paralysis can be missed. The other important fact is that a temporal bone fracture, which involves the otic capsule never, heals and that the patient has a higher risk of contracting meningitis. Such fractures should ideally be surgically corrected.