Lateral Internal Pterygoid Muscle

Description

Running deep to the mandibular ramus, the medial pterygoid (often called the internal pterygoid) occupies the medial surface of the angle of the mandible, while the lateral pterygoid sits superior and anterior to it in the infratemporal fossa. From a lateral head and neck cutaway, the zygomatic arch, masseter, temporalis tendon near the coronoid process, and the mandibular condyle at the temporomandibular joint (TMJ) frame the pterygoid region. The medial pterygoid fibers course inferolaterally from the pterygoid fossa and pyramidal process of the palatine bone toward the mandibular tuberosity, forming a functional sling with the masseter around the angle of the jaw. Nearby, branches of V3 and the maxillary artery logically track between and around these muscles. Mandibular mechanics are the point. The medial pterygoid elevates the mandible and assists contralateral excursion, while the lateral pterygoid draws the mandibular head and articular disc anteriorly during mouth opening and protrusion, a relationship that matters in anterior disc displacement and reduction in TMJ internal derangement. Dental local anesthesia also lives here: the inferior alveolar and lingual nerves pass close to the medial pterygoid, so technique and needle position during an inferior alveolar nerve block can irritate muscle and trigger postinjection trismus. Bleeding is not theoretical. The pterygoid venous plexus and maxillary artery branches make the infratemporal fossa an unforgiving space during surgical exposure. Use this lateral depiction when teaching masticatory muscle function in gross anatomy or dental anatomy labs, or when illustrating TMJ dysfunction, mandibular fractures near the angle, and approaches to the infratemporal fossa in oral and maxillofacial surgery and ENT publications. It also fits anesthesia training modules that need accurate spatial relationships for V3 blocks and complication counseling. Anatomical accuracy verified by SciePro's Medical Advisory Board.