Human unilateral bifid coronoid process – Report of a rare accidental radiographic finding

Abstract

Routine panoramic radiographic evaluations reveal morphological differences in the maxillofacial structures, particularly the mandible. Although bifid condyle variants are prevalent, bifid coronoid processes are rarely reported. Here a regular digital Orthopantomograph (OPG) was advised for the patient’s routine dental care, which revealed the presence of a unilateral bifid coronoid process on the right side of the jaw, which was confirmed with Cone Beam Computed Tomography (CBCT). This is notable, because it is only the second incidence of its kind to be documented.

Shifting the Spotlight From the Mandibular Condyle to the Coronoid Process: A Report of a Unique Case of Trifid Mandibular Coronoid Process

“…Lundquist and Wege reported two normally formed coronoid processes, referred to as the double coronoid process, in a 41-year-old white male on the right side of the mandible [ 13 ]. Patil et al found a unilateral bifid coronoid process on the right side of the jaw in a 58-year-old male, which was an incidental finding on the panoramic image that was later confirmed by CBCT [ 2 ]. de Gittins et al reported a case of the double coronoid process in a 61-year-old female on the left side of the jaw.…”

“…The ramus is the vertical part that unites to the body near the angle of the mandible. The superior aspect of the ramus has two processes named coronoid and condylar process [ 2 ]. The coronoid process of the mandible is a triangular plate of bone that projects upward and slightly forward [ 1 ].…”

“…It develops endochondrally from the primary ossification center, separates from Meckel’s cartilage during the initial developing stages, and later gets integrated into the ramus of the mandible in the eighth to ninth week of gestation [ 3 ]. The coronoid process provides attachment to two important muscles of mastication: the temporalis and masseter [ 2 ]. These muscles play a key role in functional movements such as mastication, swallowing, and speech, thus emphasizing the role of the coronoid process in morpho-functional dependence.…”

“…The abnormal elongation of the mandibular coronoid process, formed of histologically normal bone, is called coronoid hyperplasia. This might lead to difficulty in mastication and a decreased range of motion of the TMJ [ 2 , 7 ]. Goh et al performed a review including all the case reports and case series on coronoid hyperplasia and suggested a crucial role of the temporalis muscle in the pathogenesis of coronoid hyperplasia either directly or indirectly [ 6 ].…”

“…There are limited cases in the literature reporting variation in the number of the coronoid process such as the bifid coronoid process. Patil et al [ 2 ], Cranin [ 12 ], Lundquist and Wege [ 13 ], Kansu et al [ 14 ], and de Gittins et al [ 15 ] reported cases of bifid/double coronoid process or second coronoid process. To date, no case of trifid coronoid process has been reported.…”