External Pterygoid Nerve (or lateral pterygoid nerve): The nerve to the Pterygoideus externus frequently arises in conjunction with the buccinator nerve, but it may be given off separately from the anterior division of the mandibular nerve. External Pterygoid Nerve (or lateral pterygoid nerve): The nerve to the Pterygoideus externus frequently arises in conjunction with the buccinator nerve, but it may be given off separately from the anterior division of the mandibular nerve.