Extra-articular ankylosis of the coronoid processes to the base of the skull. A case report.

Extra-articular temporomandibular bony ankylosis between the coronoid process and the base of the skull is quite uncommon. In this paper we present a case of fusion of the right coronoid to the maxilla and sphenoid bone in an 18-year-old male. This bony ankylosis was the result of surgical removal of an odontogenic tumour from the right mandibular ramus when the patient was 4 years old. The ankylosis of the right coronoid resulted in hypoplasia of the mandible and fibrous fusion between the left coronoid and the base of the skull. The patient was treated by bilateral operation. Postoperative recurrent dislocation of the left condyle was attributed mainly to unbalanced muscle activity and to the flattening of the articular eminence of the left temporomandibular joint which had developed during the long duration of the ankylosis. This was successfully treated by left condylectomy.