Maxilla

The maxilla is an important bone in the upper jaw of vertebrates, including humans. It forms when two smaller bones join together. In people, the maxilla makes up the front part of the upper jaw and includes the hard palate, which forms the roof of the mouth. This structure works with the mandible, or lower jaw, to help us chew food and speak. The maxilla and mandible both form from two bones that join, creating a strong jaw.

Anatomy

The maxilla is a bone in the upper part of the jaw. In people, it helps form the front part of the roof of the mouth and the sides of the nose. It is made from two bones that join together.

The maxilla has several important parts, including a main body and four parts that extend out. It also has special features like the maxillary sinus, a small space inside the bone. As we grow, the maxilla changes shape and size, especially as our teeth come in and the sinus grows larger.

Function

The maxilla is the upper part of the jaw. It holds the top teeth and connects to the cheek bones on the sides.

The maxilla helps shape important parts of our face. It forms the roof of the mouth, the bottom and sides of the nose area, and the wall around the eye. It also helps create small pits and openings in the skull.

Clinical significance

A maxilla fracture is a type of facial fracture. These injuries can happen because of facial trauma, such as violence, falls, or automobile accidents. Doctors use the Le Fort classification to organize these fractures into different groups.

In other animals

In some animals like bony fish, the maxilla is called the "upper maxilla", and the lower jaw is called the "lower maxilla". Birds have an upper jaw called the "upper mandible".

In most animals, the front part of the upper jaw where incisors are attached in mammals is made of a separate pair of bones called the premaxillae. These join with the maxilla to form the bone found in humans and some other mammals. In bony fish, amphibians, and reptiles, both the maxilla and premaxilla are flat bones that form the sides of the upper jaw and part of the face. The premaxilla also forms the lower edge of the nostrils. In mammals, these bones curve inward to help form the roof of the mouth.

Birds do not have a maxilla in the strict sense. The part of their beaks that corresponds to it (mostly the premaxilla) is called the "upper mandible".

Cartilaginous fish, such as sharks, do not have a true maxilla. Their upper jaw is formed from a cartilaginous bar that is not the same as the bone found in other vertebrates.

Additional images

• Skull. Maxilla shown in green.

Skull. Maxilla shown in white.