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Dissection View of the Left Infratemporal Fossa and Proximal Neck

Surgical Correlation


Dissection view of the left infratemporal fossa and proximal neck. The mandibular ramus, zygomatic arch, greater wing of sphenoid, and squamous portion of the temporal bone have been removed. The infratemporal fossa is exposed and the inferior head of the lateral pterygoid is shown arising from the lateral surface of the lateral pterygoid plate and inserting into the fovea on the medial aspect of the neck of the mandible (removed). Emerging between the two heads of the lateral pterygoid muscle is the buccal nerve, a sensory branch of the mandibular nerve. In addition, the maxillary artery emerges between these two heads prior to entering the pterygopalatine fossa through the pterygomaxillary fissure. 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 near the neck of the mandible. The maxillary artery enters the infratemporal fossa by passing between the neck of the mandible and the sphenomandibular ligament (first or mandibular part of the maxillary artery). It then passes deep (sometimes superficial) to the inferior head of the lateral pterygoid muscle (second or pterygoid part), and its third or pterygopalatine part lies anterior to the lateral pterygoid before it passes through the pterygomaxillary fissure into the pterygopalatine fossa. Branches of this third part appear deep within the infratemporal fossa, including the 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 the proximal portions of the anterior and middle scalene muscles. 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 palatopharyngeus. The submandibular, muscular, and carotid triangles overlie contents and boundaries of those spaces. (Image courtesy of PA Rubino)