Anatomy and Development of the Maxilla
- The maxilla is a paired bone that consists of the body, four processes, and three surfaces.
- The body of the maxilla is pyramid-shaped and contains the maxillary sinus.
- The four processes of the maxilla are the zygomatic process, frontal process, alveolar process, and palatine process.
- The maxilla has three surfaces: anterior, posterior, and medial.
- Features of the maxilla include the infraorbital sulcus, canal, and foramen, the maxillary sinus, and the incisive foramen.
- The maxilla is ossified from two centers: one for the maxilla proper and one for the premaxilla.
- These centers appear during the sixth week of prenatal development and unite in the beginning of the third month.
- The maxillary sinus develops as a shallow groove on the nasal surface of the bone around the fourth month of development.
- The maxilla was formerly described as ossifying from six centers, including the orbitonasal, zygomatic, palatine, premaxillary, nasal, and infravomerine centers.
- Changes in the maxilla occur with age, with the vertical diameter becoming the greatest due to the development of the alveolar process and the increase in size of the sinus.
- The maxilla continues to grow until adulthood.
Function and Role of the Maxilla
- The alveolar process of the maxillae holds the upper teeth and forms the maxillary arch.
- Each maxilla assists in forming the boundaries of three cavities: the roof of the mouth, the floor and lateral wall of the nasal cavity, and the wall of the orbit.
- Each maxilla also contributes to the formation of two fossae: the infratemporal and pterygopalatine, and two fissures: the inferior orbital and pterygomaxillary.
- The maxilla can be fractured, often as a result of facial trauma, and is classified according to the Le Fort classification.
- The maxilla provides support for the facial structure.
- It helps in chewing and biting food.
- The maxilla plays a role in speech production.
- It contributes to the aesthetic appearance of the face.
- The maxilla assists in the proper alignment of the teeth.
Maxilla in Other Animals
- In most vertebrates, the foremost part of the upper jaw consists of a separate pair of bones called the premaxillae, which fuse with the maxilla proper in humans and some other mammals.
- In bony fish, amphibians, and reptiles, both maxilla and premaxilla are relatively plate-like bones, forming only the sides of the upper jaw and part of the face.
- In mammals, the bones have curved inward, creating the palatine process and forming part of the roof of the mouth.
- Birds do not have a maxilla in the strict sense; the corresponding part of their beaks, mainly consisting of the premaxilla, is called the upper mandible.
- Cartilaginous fish, such as sharks, lack a true maxilla and instead have an upper jaw formed from a cartilaginous bar.
Common Maxillary Conditions and Disorders
- Cleft lip and palate can affect the maxilla.
- Maxillary fractures can occur due to trauma.
- Maxillary sinusitis is an inflammation of the maxillary sinuses.
- Maxillary tumors or cysts can develop in the bone.
- Maxillary hypoplasia is an underdevelopment of the maxilla.
Surgical Procedures Involving the Maxilla
- Maxillary osteotomy is a surgical procedure to reposition the maxilla.
- Le Fort I, II, and III osteotomies are specific maxillary procedures.
- Maxillary sinus augmentation is a procedure to increase bone height in the maxilla.
- Maxillary distraction osteogenesis is used to lengthen the maxilla.
- Maxillary implant placement is a common dental procedure.
This article needs additional citations for verification. (December 2007) |
The maxilla (pl.: maxillae /mækˈsɪliː/) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw.
| Maxilla | |
|---|---|
 Side view. Maxilla visible at bottom left, in green. | |
 Front view. Maxilla visible at center, in green. | |
| Details | |
| Precursor | 1st branchial arch |
| Identifiers | |
| MeSH | D008437 |
| TA98 | A02.1.12.001 |
| TA2 | 756 |
| FMA | 9711 |
| Anatomical terms of bone | |
