Answer
The mandible is the lower jawbone. It is the largest and strongest of the face bones. This bone starts out as two halves (left and right) in the fetus with fibrocartilage connection called the mental symphysis. Later in life the cartilage ossifies so that by early childhood (the second year of life) the mandible is a single bone. The structural features of the mandible includes the following: body, rami (roots), angle, processes, protuberance, spines , notches, and foramina.
The body is the anterior part of the bone which is shaped somewhat like a horse shoe; it is disposed horizontally and extends antero-laterally to join the rami. The rami are two posterior extensions of the bone; they are disposed in an oblique to lateral manner and each ends in a u-shaped structure with a depression or notch (mandibular notch) between two processes. The anterior process is the coronoid process, and the posterior process is called the condylar process. The temporalis muscle --important in the act of biting-- is attached to the coronoid process
At the top of each condylar process is a knob-like structure-- the mandibular condyle-- that articulates with the the mandibular fossa of the temporal bone to form the temporomandibular joint (TMJ). The other notable process of the mandible is the point of the chin-- the mental protuberance--but smaller, less obvious bony projections called alveolar processes, exist on the mandible in the spaces between the teeth.
The area where the body and the ramus of the mandible meet is called the angle of the bone-- this is the place where the masseter muscle is attached to the mandible. Finally there are two prominent foramina in the mandible; these are the mental foramen and the mandibular foramen.
Work Step by Step
The mental foramen is an opening on the anterolateral surface of the body; It allows passage of the mental artery and the mental nerve -- a branch of the inferior alveolar nerve. The mandibular foramen is on the medial surface of the ramus, just below the notch. It allows passage of nerves and blood vessels that supply the lower teeth. During dental procedures dentists often injected anesthetics near the mandibular foramen to create numbness in the tissues being treated.
