Abstract
Ankylosis of the temporomandibular joint (TMJ) is a condition limiting mandibular condylar head movement. This may be due to either an intra-articular abnormality (true ankylosis), such as fusion within the joint components, or to an extra-articular abnormality (pseudoankylosis/false-ankylosis), such as physical obstruction between structures outside the joint. Trauma was noted to be one of the common causes of pseudoankylosis, the several forms of which have been reported in literature. The rarest and least reported cases are pterygomandibular related pseudoankyloses. This case report presents a rare form of pseudoankylosis which assumes unilateral elongation of the lateral pterygoid plate that mechanically impedes with an osseous projection from the medial surface of the mandibular ramus. Also, the case report presentes two radiographic modalities (Cone-Beam Computed Tomography vs Orthopantomography), that highlight their diagnostic values for such a condition.