Abstract
The patient was a girl of 19 years old whose chief complaint was hard of hearing. No abnormal finding was seen on otoscopic examination, but the hypoplasia of the mandible and anti-mongoloid inclination of the palpebral fissures were found.
On exploring the middle ear cavity, it was found that the incus on each side were malformed. Tympanoplasty was performed on each ear with remarkable improvement of hearing.
It was suggested by operative findings that stapes and long process of incus were dirived from the second branchial arch (Reichert's cartilage).
