Lateral perspective of the infratemporal fossa. The zygomatic arch and the coronoid process of the mandible have been removed to expose the infratemporal fossa. Within the infratemporal fossa lies the lateral pterygoid muscle (with its superior and inferior heads), the medial pterygoid muscle (an unlabeled portion of this is seen passing deep to the ramus of the mandible toward the angle), and the maxillary artery, with its branches to the pterygoid muscles and deep temporal arteries that ascend to the temporal fossa on the deep surface of the temporalis muscle. The spinal accessory nerve (cranial nerve XI) courses posteriorly and inferiorly over the internal jugular vein and deep to the sternocleidomastoid muscle supplying it and more distally, the trapezius muscle.