Ossicular chain disruption (temporal bone fracture)

Case contributed by Jan Frank Gerstenmaier


Acute conductive hearing loss on the left following head trauma.

Patient Data

Age: 25 years
Gender: Female

CT temporal bones


On the left, there is a fracture in orientation parallell to the long axis of the temporal bone. There is malalignment of the incudomalleolar joint, and also malalignment of the incudostapedial joint.

The right side is normal.

Normal and abnormal incudomalleolar joint alignments


These spot images from this case illustrate the normal ice cream and cone relationship of incus and malleolus on the right, and the abnormal alignment on the left. 

The image of the ice cream cone is from Wikimedia Commons and in the public domain. The flavor is strawberry.

Case Discussion

Longitudinal temporal bone fractures are more common than the transverse type. Conductive hearing loss in can be due to middle ear hemorrhage, or as in this case due to ossicular chain disruption. In any case of temporal bone fracture, ossicular joint alignments should be assessed. The ice cream cone sign is helpful in determining whether the incudomalleolar articulation is normal.

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