Congenital Cochlear Eponyms

• Mondoni defect: Most common congenital cochlear deformity. Incomplete development of the 2.5 turns of the cochlea, with a relatively well-formed basal turn and ballooning of the middle and apical turns into a cyst. 20% of cases have associated enlarged endolymphatic sacs and vestibular aqueducts.
• Cock deformity: Also known as Michel dysplasia. Second most common congenital cochlear deformity. Common cavity of the vestibule and cochlea. The modiolus is absent. Semicircular canals may be affected.
• Michel aplasia: Complete absence of the inner ear structures. Associated with other skull base abnormalities, abnormal course of the facial nerve, jugular vein abnormalities, absent stapes, absent oval window.

References

Neuroradiology: The Requisites (2nd ed). pp 592-594.