Lateral perspective of the left mandibular region. For orientation, the left side of the image is anterior. The masseter muscle covers the ramus of the mandible and the sternocleidomastoid muscle has been retracted posteriorly. The common carotid artery can be seen bifurcating into the internal and external carotid arteries (ECA). Branches of the ECA visible here include the facial artery and the superficial temporal artery, which runs over the zygomatic root anterior to the external auditory canal. The posterior digastric muscle runs anteroinferiorly from the digastric notch of the temporal bone to an intermediate tendon (shared with the anterior digastric muscle) that attaches to the hyoid bone. After exiting the stylomastoid foramen, the facial nerve passes deep to the posterior digastric to enter the parotid space. It gives rise to motor branches to this muscle and the stylohyoid before passing into the substance of the parotid gland (removed) superficial to the ECA. Here, terminal branches arise that emerge from the gland to the muscles of facial expression in the face, scalp, and neck. (Image courtesy of AL Rhoton, Jr.)