Anatomy of the Mandibular Body (Corpus mandibulae)
The foundation of the bone is its body, termed Corpus mandibulae. The body has two primary margins, each with distinctive features. The inferior margin is thick and robust, known as the base of the mandible (Basis mandibulae).
On the anterior external surface of the body along the midline, the mental protuberance (Protuberantia mentalis) projects forward. Flanking this protuberance are the paired mental tubercles (Tuberculum mentale). Moving laterally along the external surface of the body, one encounters the important mental foramen (Foramen mentale). This serves as the exit point of the mandibular canal (Canalis mandibulae), which runs through the interior of the bone.
Internal Surface of the Body
The inner aspect of the body features prominent relief. Right along the midline are the superior and inferior mental spines (Spinae mentales superior et inferior). Lateral to these spines lies the digastric fossa (Fossa digastrica).
Special attention should be paid to the fossae on the internal surface. Superior and posterior to the digastric fossa is the sublingual fossa (Fovea sublingualis). Inferior and further posterior lies the larger submandibular fossa (Fovea submandibularis). A bony ridge—the mylohyoid line (Linea mylohyoidea)—serves as the clear anatomical boundary separating these two fossae.
Alveolar Part and Dental Structures
The superior margin of the body has a more complex structure designed to anchor the teeth and is called the alveolar part (Pars alveolaris). Functionally and structurally, it corresponds to the alveolar process of the maxilla. Together, this region forms the curved alveolar arch (Arcus alveolaris).
Within this arch are sockets for the tooth roots—dental alveoli (Alveoli dentales). Adjacent alveoli are separated by bony interalveolar septa (Septa interalveolaria). If a tooth has multiple roots, additional interradicular septa (Septa interradicularia) are present within a single alveolus. The external surface of the bone in this area is uneven, with the tooth roots forming characteristic alveolar juga (Juga alveolaria).
Immediately posterior to the last molar lies a flat area—the retromolar triangle (Trigonum retromolare), which is posteriorly bounded by the retromolar fossa (Fossa retromolaris).
Ramus of the Mandible (Ramus mandibulae)
Projecting upward from the posterior part of the bone body are the paired rami of the mandible (Ramus mandibulae). The external surface of the ramus features the oblique line (Linea obliqua). On the internal surface, the buccinator line (Linea buccinatoria) is occasionally described, though modern anatomical terminology generally omits this term.
The junction where the inferior margin of the body meets the posterior margin of the ramus forms the angle of the mandible (Angulus mandibulae). This angle bears roughened areas on both sides: the masseteric tuberosity (Tuberositas masseterica) on the outside, and the pterygoid tuberosity (Tuberositas pterygoidea) on the inside.
Processes and Foramina of the Ramus
The superior part of the ramus terminates in two distinct processes, separated by the deep mandibular notch (Incisura mandibulae).
- Condylar process (Processus condylaris) — the posterior process. It consists of the expanded head of the mandible (Caput mandibulae) and the narrowed neck (Collum mandibulae). The pterygoid fovea (Fovea pterygoidea) is located on the medial side of the neck.
- Coronoid process (Processus coronoideus) — the anterior process. It is pointed and transitions anteriorly into the temporal crest (Crista temporalis).
On the medial (internal) surface of the ramus, slightly inferior to the notch, opens the mandibular foramen (Foramen mandibulae). Inferiorly, this foramen is bounded by a bony projection known as the lingual of the mandible (Lingula mandibulae). This foramen marks the beginning of the mandibular canal (Canalis mandibulae), which courses through the bone body to the mental foramen. Descending forward and downward from the lingula along the internal surface is the mylohyoid groove (Sulcus mylohyoideus).