Coronoid Hyperplasia (Jacob’s Disease) as a Rare Cause of Restricted Mouth Opening: a Case Report

Restricted mouth opening (MO) is associated with the problems in intra/extra-articular components such as trauma to the articular bone component especially at the early ages, chronic displacement of the articular disk, tumors, condylar anomalies, coronoid hyperplasia and hyperactivity of jaw muscles. A pseudo-joint can form between the zygoma and the hyperplastic coronoid process (Jacob’s disease). Pseudo-joint restricts MO, it causes multiple problems for patients, and finally it decreases the quality of their or patients’ lives.
Therefore, early diagnosis and treatment are very important. Case Report: Described here is a 28-year-old man that due to trauma in childhood, his coronoid process became hyperplastic. The pseudo-joint formed between coronoid process and zygomatic bone interfere with MO.

The intraoral approach offers direct access without the risk of facial nerve injury or scars on the face