Etiology of coronoid fractures: motor vehicle accidents, interpersonal violence, sport injuries, and falls. Less commonly, fractures are caused during mandibular third molar extraction and bad split during mandibular sagittal split osteotomy.^1,2,3

The zygomatic arch protects the coronoid process along its lateral aspect. The temporalis muscle attaches to the lateral surface of the coronoid process.

Fracture of the zygomatic arch with medial displacement of fragments can often impinge on the coronoid process of the mandible and cause trismus.^1,3,4

Clinical exam demonstrates several symptoms, most commonly a limitation in mouth opening and in lateral movement of the mandible.

In some cases, swelling and hematoma can be present; occlusion disturbance is less common and is usually related to other mandibular fractures.^1,3,4

Plain radiographs or panoramic radiographs can be helpful, but the standard is computed tomography (CT) scans (FIG 1).

Treatment of coronoid process fractures can be divided into three categories:

Nonoperative management is advocated in cases of minimally displaced coronoid process fractures, absence of mouth opening limitation or trismus, and usually when the fracture is solitary.

In cases of concomitant zygomatic arch fractures, one should consider closed reduction of the arch fracture only.