Figure 3: Mandible of human embryo 24 mm. long. Outer aspect.

Figure 4: Mandible of human embryo 24 mm. long. Inner aspect.

Figure 5: Mandible of human embryo 95 mm. long. Outer aspect. Nuclei of cartilage stippled.

Figure 5: Mandible of human embryo 95 mm. long. Inner aspect. Nuclei of cartilage stippled.

The mandible is ossified in the fibrous membrane covering the outer surfaces of Meckel's cartilages. File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... It has been suggested that this article or section be merged with jaw. ...

These cartilages form the cartilaginous bar of the mandibular arch (see p. 66), and are two in number, a right and a left.

Their proximal or cranial ends are connected with the ear capsules, and their distal extremities are joined to one another at the symphysis by mesodermal tissue. A symphysis is a fibrocartilaginous fusion between two bones. ...

They run forward immediately below the condyles and then, bending downward, lie in a groove near the lower border of the bone; in front of the canine tooth they incline upward to the symphysis. In oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or (in the case of those of the upper jaw) eye teeth, are relatively long, pointed teeth, evolved (and used, in most species where they remain prominent) primarily for firmly holding food in order to tear it apart, and... A symphysis is a fibrocartilaginous fusion between two bones. ...

From the proximal end of each cartilage the malleus and incus, two of the bones of the middle ear, are developed; the next succeeding portion, as far as the lingula, is replaced by fibrous tissue, which persists to form the sphenomandibular ligament. The malleus is hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum. ... This article refers to a bone in the mammalian ear. ... The sphenomandibular ligament (internal lateral ligament) is a flat, thin band which is attached above to the spina angularis of the sphenoid bone, and, becoming broader as it descends, is fixed to the lingula of the mandibular foramen. ...

Between the lingula and the canine tooth the cartilage disappears, while the portion of it below and behind the incisor teeth becomes ossified and incorporated with this part of the mandible.

Ossification takes place in the membrane covering the outer surface of the ventral end of Meckel's cartilage (Figs. 178 to 181), and each half of the bone is formed from a single center which appears, near the mental foramen, about the sixth week of fetal life.

By the tenth week the portion of Meckel's cartilage which lies below and behind the incisor teeth is surrounded and invaded by the membrane bone.

Somewhat later, accessory nuclei of cartilage make their appearance:

• a wedge-shaped nucleus in the condyloid process and extending downward through the ramus;
• a small strip along the anterior border of the coronoid process;
• smaller nuclei in the front part of both alveolar walls and along the front of the lower border of the bone.

These accessory nuclei possess no separate ossific centers, but are invaded by the surrounding membrane bone and undergo absorption. (ramus mandibulæ; perpendicular portion) The ramus of the mandible is quadrilateral in shape, and has two surfaces, four borders, and two processes. ...

The inner alveolar border, usually described as arising from a separate ossific center (splenial center), is formed in the human mandible by an ingrowth from the main mass of the bone.

At birth the bone consists of two parts, united by a fibrous symphysis, in which ossification takes place during the first year.

The foregoing description of the ossification of the mandible is based on the researches of Low 44 and Fawcett, 45 and differs somewhat from that usually given.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant. The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body, commonly known as Grays Anatomy, is an anatomy textbook widely regarded as a classic work on human anatomy. ...