Maxilla

Your upper jaw is a bone.

It stays still in your face. This bone holds your top teeth. It also helps make the roof of your mouth.

This bone is made of two parts joined together. It also helps make the floor of your nose. It helps make the space around your eyes. This bone grows as you get older. It gets taller as your teeth grow in. It is a very important part of your face.

The maxilla is your upper jaw bone.

It is made of two bones joined together. These two bones meet at a line called a suture. In humans, this bone also helps make the hard palate. The hard palate is the roof of your mouth.

The maxilla has many important parts. One part is the alveolar process. This part holds your upper teeth in place. Another part is the maxillary sinus. This is a hollow space inside the bone. At birth, this space looks like a small groove. It grows much larger as you get older.

This bone connects to nine other bones in your face. It helps form the floor of your nose. It also helps make the walls of your eye sockets. The maxilla can break if you have a hard fall. This is called a facial fracture.

In other animals, the jaw works differently. Some fish have a maxilla that looks like a flat plate. Birds have a beak part called an upper mandible. Sharks do not have a true maxilla at all.

The maxilla is a very important bone in your face. It is the bone that makes up your upper jaw. In humans, this bone also helps form the hard palate. The hard palate is the firm roof of your mouth.

The maxilla is actually a paired bone. This means there are two bones that join together. They meet at a line called the intermaxillary suture. This joint forms a small point called the anterior nasal spine. It works much like your lower jaw bone. The lower jaw is called the mandible. Both the maxilla and the mandible are made of two bones fused together.

This bone has a very special way of working. It has a pyramid shape with several different surfaces. One part is called the alveolar process. This part acts like a holder for your upper teeth. The bone also creates several hollow spaces and paths. One important space is the maxillary sinus. This is a hollow area inside the bone. The maxilla also helps build the walls of your eye sockets. It helps form the floor of your nose too. It even helps make the roof of your mouth.

Scientists have studied how this bone grows for a long time. Some experts, like Mall and Fawcett, have shared their findings. They believe the bone grows from two main centers. One center is for the maxilla itself. The other center is for the premaxilla. These two centers start to appear during the sixth week before a baby is born. They join together by the start of the third month. However, a line stays between them on the palate for a long time. This line can last until you are nearly middle-aged.

There are many specific details about the maxilla's shape. At birth, the bone is wider than it is tall. The body of the bone is mostly just the part that holds teeth. The maxillary sinus looks like a small groove in a newborn. As you grow, the bone changes its shape. The vertical part becomes the longest part of the bone. This happens because the teeth sockets and the sinus grow larger. The bone connects with nine different bones in the head. These include the frontal, nasal, and zygomatic bones.

Different animals have different types of jaws. In most vertebrates, the very front part of the jaw is separate. This part is called the premaxilla. In humans, this fuses with the maxilla. In bony fish and reptiles, the bones are more like flat plates. Birds do not have a true maxilla. They call the part of their beak the upper mandible. Sharks are also different from us. They do not have a true maxilla at all. Instead, their upper jaw is a bar made of cartilage.

The maxilla is a critical bone in the vertebrate skull. In humans, it serves as the upper jaw. It is a paired bone, meaning there are two maxillae. These two bones join together at the intermaxillary suture. This connection forms a small point called the anterior nasal spine. While the lower jaw, or mandible, is movable, the maxilla is generally fixed in place.

This stability is important for many bodily functions. The maxilla helps build the structure of the face. It also forms the boundaries for several important cavities in the head.

The anatomy of the maxilla is quite complex. The main body of the bone is pyramid-shaped. It features several distinct surfaces, including the orbital, nasal, infratemporal, and facial surfaces. The bone also has four specific processes. These are the zygomatic process, the frontal process, the alveolar process, the palatine process, and the orbital surface. The alveolar process is particularly important. It forms the maxillary arch, which holds the upper teeth in place.

Inside the bone, there is a hollow space called the maxillary sinus. The bone also contains paths like the infraorbital canal and the incisive foramen.

Because of its shape, the maxilla helps create several structural boundaries. It assists in forming the roof of the mouth, also known as the hard palate. It also forms the floor and the lateral wall of the nasal cavity. Additionally, the maxilla helps build the walls of the orbit, which is the eye socket. It contributes to the formation of two fossae: the infratemporal and pterygopalatine. It also helps form two fissures, which are narrow openings called the inferior orbital and pterygomaxillary fissures.

Scientists have different theories about how the maxilla develops. Some researchers, such as Mall and Fawcett, suggest the bone ossifies from two centers. One center is for the maxilla proper, and the other is for the premaxilla. These centers appear during the sixth week of prenatal development. They unite by the beginning of the third month of development. However, the suture between these two parts can remain on the palate until nearly middle life.

Other older descriptions suggested the bone might ossify from six different centers. These included the orbitonasal, zygomatic, palatine, premaxillary, nasal, and infravomerine centers.

The appearance of the maxilla changes significantly as a person ages. At birth, the bone is wider than it is tall. The frontal process is very well-marked at this stage. Most of the bone consists of the alveolar process, with tooth sockets reaching almost to the floor of the orbit. The maxillary sinus appears only as a shallow groove on the nasal surface. As an adult grows, the vertical diameter becomes the largest part of the bone. This change happens because the alveolar process and the maxillary sinus increase in size.

The maxilla connects with many other parts of the skull. Each maxilla articulates with nine different bones. These include the frontal, ethmoid, nasal, zygomatic, lacrimal, and palatine bones. It also connects with the vomer and the inferior nasal concha. Finally, it joins with the maxilla on the opposite side of the face.

Because it is a facial bone, it can be injured. A maxilla fracture is a type of facial fracture. These often result from trauma like falls or automobile accidents. Doctors use the Le Fort classification to categorize these fractures.

Different animals show different ways of forming the upper jaw. In most vertebrates, the very front part of the upper jaw is a separate pair of bones called the premaxillae. In humans, these fuse with the maxilla. In bony fish, amphibians, and reptiles, the maxilla and premaxilla are plate-like bones. They form the sides of the upper jaw and part of the face. In birds, the upper jaw is called the upper mandible and consists mainly of the premaxilla. Cartilaginous fish, like sharks, do not have a true maxilla. Their upper jaw is instead a cartilaginous bar that is not homologous to the bone in other vertebrates.