First branchial arch

The first branchial arch, also called the first pharyngeal arch and mandibular arch, is the first of six branchial archesthat develops in fetal life. It is located between the stomodeumand the first pharyngeal groove.

This arch divides into a maxillary processand a mandibular process, which are the bonesof the middle third and lower third of the faceand contain the arches of the jaws. The maxillary process becomes the maxilla, or upper jaw, and palate.

A cartilage (Meckel's cartilage) forms in the mesodermwhich becomes the incusand malleusof the middle ear; the anterior ligament of the malleus and the sphenomandibular ligament. The mandibleor lower jaw forms by intramembranous ossification.

The artery of the first arch is the first aortic arch, which partially persists as the maxillary artery.

The nerveassociated with the first branchial arch is the trigeminal nerve(mandibular branch). Note that maxillary process also carries its own branch of the trigeminal nerve, the maxillary. The associated cartilage is Meckel's cartilage. The associated muscles are the muscles of mastication.

Derivatives of the first arch:

• Ectodermal and endodermal
  • mucous membrane and glands of the anterior two thirds of the tongue
• Mesodermal
  • muscles of mastication (chewing)
    • masseter
    • pterygoidmuscles
    • temporalismuscles
  • mylohyoid muscle
  • digastric muscle, anterior belly
  • tensor palati muscle
  • tensor tympani muscle

Sources

• Harris, Edward F., 2002. Craniofacial Growth and Development.
• McMinn, R., 1994. Last's anatomy: Regional and applied (9th ed).

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/First+branchial+arch Wikipedia article First branchial arch.