What Is the Gonion?

The gonion is located on the mandible, which is also known as the lower jaw, the jawbone, or the inferior maxillary bone, and is the point of the mandible's maximum curvature. The area of the jawbone where the gonion is located is called the angle of the mandible. The arched rear part of the jawbone that's located below the ear is the angle of the mandible. This part of the jawbone forms a curved ridge, the crest of which is called the gonion.

There are five main sections of the mandible, which are the body, the ramus mandibulae, the alveolar process, the condyle or condyloid process, and the coronoid process. The body of the mandible is horseshoe-shaped, and the chin is its most forward, or anterior, prominence. The two rami, or ramus mandibulae, connect at right angles to the ends of the mandibular body and provide attachment for the masseter, which is a muscle of mastication. There is one ramus on either side of the jaw.

The alveolar process is the part of the mandible that cradles the teeth. The condyle is the upper rear projection of the ramus which consists of two parts — the condyle is the broad uppermost part, and it's supported by the neck, which is comparatively thinner. The condyle helps to form the temporomandibular joint, which is where the mandible and the cranial temporal bone join together.

The coronoid process is the upper front projection of the ramus. It's a thin, flat, triangular emanation of the ramus, and its overall size and shape varies from person to person. The coronoid process provides attachment to the temporal muscle, which is also known as the temporalis muscle and is one of the muscles of mastication. The deep concavity between the condyle and the coronoid process is called the mandibular notch, and it permits the passage of the masseteric artery, masseteric vein, and the masseteric nerve, which is a division of one of the three branches of the trigeminal nerve called the mandibular nerve.

The ramus extends down from the coronoid process and the condyle to its lowest point, which is the angle of the mandible. The point at which the angle of the mandible joins to the body of the mandible is called the gonion. It serves no anatomical function other than as a craniometric landmark from which measurements can be taken. One gonion is found on both sides of the mandible.