Longitudinal Temporal Bone Fracture with Incudomalleal dislocation

Findings:

A linear radiolucency extends in a longitudinal direction through the right mastoid air cells with subtle air cell opacification. The right malleus head is displaced medially from its expected normal position on the incus body. The normal ossicular relationships are shown on the left.

Discussion/Differential Diagnosis:

Longitudinal temporal bone fractures comprise 70-90% of all temporal bone fractures compared to transverse fractures. In this case there is a linear radiolucency going longitudinally on the right side of the patient with a distinct dislocation of the Incudo-malleolar jointwhereas the left side presents as normal. These cases often present with periauricular swelling and may cause conductive hearing loss and pneumocephalus, as well as facial paralysis in 20% of cases. Ossicular dislocation is more common with longitudinal fractures than transverse, and the incidence of sesorineural hearing loss is higher with transverse than longitudinal fractures.

Case contributed by Josh Hall, UC undergraduate.

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