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Left Mandibular Ramus and Surrounding Structures

Surgical Correlation


Left mandibular ramus and surrounding structures. The zygomatic arch and associated masseter muscle have been removed to expose the ramus of the mandible. Its condylar process articulates with the mandibular fossa of the temporal bone to form the temporomandibular joint. The lateral pterygoid muscle (not labeled) can be seen through the mandibular notch while the temporalis muscle attaches to the coronoid process. The buccinator muscle forming  the wall of the cheek attaches posteriorly to the pterygomandibular raphe and alveolar processes of molar regions of the upper and lower jaws. Deep to the temporalis, skull bone and meninges have been removed to expose the cerebrum, cerebellum, and superior petrosal vein. Behind the ramus of the mandible the external carotid artery is seen before it divides into its terminal maxillary and superficial temporal branches. It normally ascends through the parotid gland, which has been removed. The transverse facial artery arises from the superficial temporal as does the zygomaticoorbital artery. At a deeper plane, the internal jugular vein lies superficial to the internal carotid artery with the vagus nerve descending in the neck between these two vessels. The hypoglossal nerve is also visible and near the origin of the external carotid artery gives off from its epineurial sheath C1 nerve fibers as the superior root of the ansa cervicalis. These fibers are part of the motor nerve supply to the infrahyoid muscles. Removal of the sternocleidomastoid and deep neck musculature has exposed the suboccipital muscles, obliquus capitis inferior and superior. A portion of the vertebral artery is shown before it enters the transverse foramen of the atlas. It is crossed superficially by the ventral ramus of the C2 spinal nerve. Emerging from beneath the obliquus capitis inferior is the greater occipital nerve, the dorsal ramus of C2, which supplies most of the posterior scalp. (Image courtesy of PA Rubino)