Lower jaw
Last reviewed: 23.04.2024
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The lower jaw (mandibula) is the only mobile skull bone. The unpaired lower jaw has a body and two branches.
The body of the lower jaw (corpus mandibulae) is curved by the convexity forward. The lower edge of the body, its base, is thickened and rounded, the upper margin forms an alveolar arc (arcus alveolaris). On the alveolar arch there are holes - dental alveoli (alveoli dentales) for 16 teeth, separated by thin bone interalveolar septa. On the outer surface of the alveolar arch, there are convex alveolar elevations (juga alveolaria) corresponding to the alveoli. On the median line in the anterior part of the body of the lower jaw there is a small chin protuberance (protuberantia mentalis). Back and lateral from it at the level of the second small molar is located the chin opening (foramen mentale).
In the middle of the concave inner surface there is a small protrusion - the chin spine (spina mentalis). On either side of it is a two-abdominal fossa (fossa digastrica). Above the chin awn, closer to the alveoli, on each side is the sublingual fossa a (fossa sublingualis) - a trace of the hyoid salivary gland. The jaw-hyoid line (linea mylochiodea) goes up obliquely. Under it at the level of the molars is located the submandibular fossa (fossa submandibularis) for the salivary gland of the same name.
The branch of the lower jaw (ramus mandibulae) is paired, going up and back from the body of the lower jaw. The angle of the lower jaw (angulus mandibulae) is located at the site of the transition of the body to the branch. On its outer surface there is a chewing tuberosity (tuberositas masseterica), and on the inside - a pterygoid tuberosity (tuberositas pterygoidea). On the inner surface of the mandible branch there is an opening of the lower jaw (foramen mandibulae) leading to the eponymous canal, terminating with the chin aperture. From above the branch of the lower jaw is divided into two processes: anterior coronary and posterior condylar.
The processus coronoidus (processus coronoideus) is separated from the condylar process by means of a mandible (incisure mandibulae). From the base of the coronoid process to the last molar tooth is the buccina groin (crista buccinatoria).
The condylar processus (processus condylaris) passes into the neck of the lower jaw (collum mandibulae), which ends with the head of the lower jaw (caput mandibulae).
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