Detailed Anatomy of a Pterygomandibular Ankylosis

Pterygomandibular ankylosis is a rare condition where a bony fusion occurs between the pterygoid plate (either lateral or medial) and the ramus of the mandible. This fusion results in reduced mandibular mobility due to an extracapsular abnormality, representing a form of pseudoankylosis. In a retrospective analysis, the computed angiogram of an adult male case revealed an incomplete pterygomandibular bony fusion on the right side. The lateral pterygoid plate was abnormally broad, measuring 1.68 cm, while the inner aspect of the mandibular ramus exhibited an infraincisural spine measuring 5.58 mm, oriented medially and anteriorly toward the lateral pterygoid plate. The maxillary artery coursed along the spine, first closely applied to it and then moving superiorly, before positioning itself superficially to the inferior head of the lateral pterygoid muscle. The pterygomandibular ankylosis separated the inferior head of the lateral pterygoid muscle, located superiorly, from the medial pterygoid muscle, located inferiorly.