maxilla n : the upper jawbone in vertebrates; it is fused to the cranium [syn: upper jaw, upper jawbone] [also: maxillae (pl)]

English

Noun

1. Either of the two bones that together form the upper jaw.

Synonyms

• jawbone
• maxillary bone

Translations

• Finnish: yläleuanluu

This article is about the mammal maxilla. For arthropod maxillae, see Mouthparts; for insect maxillae in particular, see Insect mouthparts.

The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible, which is also a fusion of two halves at the mental symphysis.

Function

The alveolar process of the maxilla holds the upper teeth, and is referred to as the maxillary arch. The maxilla attaches laterally to the zygomatic bones (cheek bones).

The maxilla assists in forming the boundaries of three cavities:

• the roof of the mouth
• the floor and lateral wall of the nasal antrum
• the floor of the orbit

The maxilla also enters into the formation of two fossae: the infratemporal and pterygopalatine, and two fissures, the inferior orbital and pterygomaxillary.

Components

Each half of the fused maxilla consists of:

• The body of the maxilla
• Four processes
  • The zygomatic process
  • The frontal process
  • The alveolar process
  • The palatine process
• Infraorbital foramen

Articulations

The maxilla articulates with nine bones:

• two of the cranium: the frontal and ethmoid
• seven of the face: the nasal, zygomatic, lacrimal, inferior nasal concha, palatine, vomer, and the adjacent fused maxillary bone.

Sometimes it articulates with the orbital surface, and sometimes with the lateral pterygoid plate of the sphenoid.

Additional images

Image:Orbital_bones.png|The seven bones which articulate to form the orbit. Image:Illu facial bones.jpg|Facial bones.

See also

• Bone terminology
• Terms for anatomical location
• Ossification of maxilla
• Hypostome
• Maxillofacial surgery

References

External links