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Left Lateral Dissection of the Infratemporal Fossa and Proximal Neck

Surgical Correlation


Left lateral dissection of the infratemporal fossa and proximal neck. The mandibular ramus, zygomatic arch, greater wing of sphenoid, and squamous portion of the temporal bone have been removed. Deep to the greater wing of sphenoid and temporal bone is a portion of the brain covered by dura containing the anterior (temporal) branch of the middle meningeal artery. The infratemporal fossa is exposed and its roof is covered by the superior head of the lateral pterygoid muscle. This muscle inserts into the articular capsule and disc of the temporomandibular joint. The head of the mandible articulates with the mandibular fossa. The inferior head of the lateral pterygoid arises from the lateral surface of the lateral pterygoid plate and inserts into the fovea on the medial aspect of the neck of the mandible. Emerging between the two heads is the buccal nerve, a sensory branch of the mandibular nerve. The bulk of the medial pterygoid muscle arises from the medial surface of the lateral pterygoid plate and inserts into the medial surface and angle of the ramus of the mandible. Emerging between this muscle and the lower border of the lateral pterygoid is the inferior alveolar nerve and medial to it, the lingual nerve. The inferior alveolar artery, a branch of the maxillary artery, accompanies the inferior alveolar nerve into the mandibular canal. The mylohyoid nerve is a motor branch off the inferior alveolar and follows the body of the mandible to the mylohyoid and anterior digastric muscles. The buccinator muscle attaches to the alveolar process of the upper and lower jaws in the molar regions before entering the lips. Near the angle of the mandible (removed) are branches of the external and internal carotid arteries and the internal jugular vein. Visible branches of the external carotid include the superior thyroid, facial, and occipital arteries. The external carotid divides into its terminal branches, the maxillary and superficial temporal arteries. The maxillary artery passes deep to the lateral pterygoid muscle and branches appear deep within the infratemporal fossa, including the inferior alveolar artery, anterior deep temporal artery, posterior superior alveolar arteries, and the infraorbital artery to the orbital floor via the inferior orbital fissure. Lateral neck musculature has been removed to reveal part of the suboccipital muscles, namely, the obliquus capitis inferior and superior. The proximal portions of the anterior and middle scalene muscles are in view. In the ventral neck, attached to the hyoid bone are the sternohyoid and superior belly of omohyoid muscles, and the thyrohyoid muscle overlying the thyrohyoid membrane, through which course the internal laryngeal nerve and superior laryngeal artery into the larynx. The superior horn of the thyroid cartilage can be seen along with a portion of the inferior pharyngeal constrictor muscle. The hypoglossal nerve wraps around the root of the occipital artery and courses forward to the oral cavity superficial to the hyoglossus muscle then deep to the mylohyoid muscle. It provides motor innervation to the extrinsic and intrinsic muscles of the tongue, except palatoglossus. (Image courtesy of PA Rubino)