Anatomy & Organs

Upper jaw – structure, function & diseases

Upper jaw

The upper jaw is the largest bone in the facial skull. It forms the counterpart to the lower jaw .

What is the upper jaw?

The upper jaw ( maxilla ) is the largest bone in the human facial skull. Its counterpart is the lower jaw (mandible). The upper jaw is formed by two pairs of bones. It is firmly attached to the skull .

The maxilla separates it from three body cavities. These are the lateral wall of the nasal cavity (cavum nasi), the floor of the bony eye socket (orbita) and the hard palate (pallatum durum) in the oral cavity . The maxillary sinus (sinus maxillaris), which is one of the largest caves in the skull area, is also located in the upper jaw.

The upper jaw is an important part of the facial skeleton. It is important for eating and influences speech and appearance. There is a firm adhesion with the cheekbone and the nasal bone . However, the upper jaw is only indirectly connected to the lower jaw.

Anatomy & Structure

The body of the upper jaw can be divided into four different areas. The facial surface (facies anterior) can be found at the front edge of the body of the upper jaw. At the rear edge of the facial surface lies the underside of the temples (Facies infratemporalis). The orbital surface (facies orbitalis) of the upper jaw provides the lower border of the orbit.

The lateral portion of the nasal cavity boundary is formed by the nasal surface (Facies nasalis). Since the upper surface of the upper jaw is not smooth and flat, it has a number of indentations, protrusions and projections. Between the frontal bone, the lacrimal bone and the nasal bone is the frontal process (processus frontalis), which serves as a connecting structure. The zygomatic process (zygomatic process) can be found on the lower edge of the orbital surface. The alveolar process (Processus alveolaris), which has the shape of an arch, performs an important task. It carries the teeth , which are extremely important for chewing .

Another structure of the upper jaw is the palatal process (Processus palatinus). This plate-like structure is located between the nasal surface and the alveolar process and forms the hard palate.

The upper jaw is supplied by various nerves and vessels. This includes the upper jaw nerve (Nervus maxillaris), which splits off from the Nervus trigeminalus, the fifth cranial nerve. From this nerve cord gives off a smaller cord called the infraorbital nerve. The nerve runs through the upper jaw and takes over the supply of teeth and bones. The maxillary artery (Arteria maxillaris) is responsible for the blood supply to the upper jaw. This blood vessel is a direct continuation of the outer part of the carotid artery (Arteria carotis externa).

Function & Tasks

Like the lower jaw, the upper jaw is also important for the absorption of food. The teeth play a crucial role in this. The periodontium provides a relatively firm anchorage in the upper jaw. In contrast to the lower jaw, the upper jaw is not mobile because the temporomandibular joint only triggers movements of the lower part of the jaw. However, just like its counterpart, it affects the visual appearance of a person. Likewise, a person’s pronunciation is influenced by it.

The periodontium, which belongs to both the upper and lower jaw, performs various protective functions. It is made up of different parts. These include the alveoli, which are small indentations in the jawbone . The root part of a single tooth is found in the alveoli.

Other important components of the periodontium are the root skin (periodontium), the cementum (cementum) and the gums (gingiva propria). However, the teeth are not completely fixed in the jawbone. Each tooth is suspended from a Sharpey fiber, a bundle of collagen fibers. This allows the tooth to remain relatively mobile. In addition, the pressure loads when chewing are distributed over a larger area.

Diseases

Various complaints and diseases can occur in the upper jaw. The most common injury is a fracture of the upper jaw (Fractura maxillae). This leads to fracture lines that have typical courses. These correspond to the weak spots in the bone architecture. A fracture of the upper jaw is usually caused by falls, sports accidents, traffic accidents or fights. A maxillary fracture accounts for around 15 percent of facial fractures.

One of the most common diseases of the upper jaw is inflammation of the maxillary sinus (sinusitis maxillaris). The maxillary sinus is one of the paranasal sinuses . The inflammation is caused by viruses or bacteria that negatively change the mucous membrane in the paranasal sinuses. Inflammation of the maxillary sinus can be both acute and chronic. The acute form is noticeable through headaches , feelings of pressure in the head region, considerable malaise and high fever. The acute form sometimes turns into the chronic form. This happens when there is insufficient healing of an inflammation. A maxillary sinus infection can also occur after a tooth has been extracted from the upper jaw. Treatment is usually with antibiotics .

In addition to injuries and illnesses, malformations are also possible in the area of ​​the upper jaw. This includes the cleft lip and palate , also known as the harelip. In Germany, around 1,500 children are born with this malformation every year. It is more common in boys than girls and can cause speech problems. It is not uncommon for congenital jaw misalignments to result in a disproportion between the teeth of the upper and lower jaw. As a result, they no longer fit together exactly. As a result, not only visual impairments often occur, but also problems with eating and speaking.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.