General Medical Information

Mandible

Susan D. John
Michael D. Maves

The mandible, or lower jaw, consists of the tooth-bearing body and the ramus that extends upward from the angle of the mandible. The ramus, including the angle, is covered externally by the masseter muscle, which is crossed by the facial nerve and parotid duct. Between the ramus and the medial pterygoid muscle are the inferior alveolar and lingual nerves. Overlapping the posterior border of the ramus is the parotid gland, and within and paralleling this border is the upper portion of the external carotid artery. The superficial branch of this artery emerges from the parotid gland behind the temporomandibular joint, and its internal maxillary branch runs transversely deep to the ramus. Inferiorly and medially, the angle and posterior part of the body of the mandible are related to the submandibular gland, and medially, the anterior part of the mandible is adjacent to the sublingual glands. The musculature most intimately concerned with the mandible and its movements consists of the masseter, temporal, and two pterygoid muscles. These muscles govern mastication and are innervated by the third division of the trigeminal nerve.