What bones forms the upper jaw?

The maxilla is a paired bone of the skull that contains an air-filled cavity called the maxillary sinus. This bone is a part of the viscerocranium of the skull.

Both maxillary bones (maxillae) are fused in the midline by the intermaxillary suture to form the upper jaw. The fusion of both maxillae creates a projection called the anterior nasal spine, which is the anterior point of the upper jaw that serves as a cephalometric landmark.

Each maxilla has five parts, including the central body of the maxilla and four processes:

• Frontal process
• Zygomatic process
• Palatine process
• Alveolar process

Body of maxilla

The body is the central portion of the maxilla. It houses the maxillary sinus and supports all four processes.

The maxillary body has four surfaces: anterior, orbital, nasal and infratemporal. 

• The anterior surface features the following landmarks:
  • Nasal notch - located on the medial margin close to the anterior nasal spine;
  • Infraorbital margin - forms the inferior margin of the orbit;
  • Infraorbital foramen - situated below the middle part of the infraorbital margin;
  • Canine fossa - located inferior to the infraorbital foramen.
• The orbital surface is the superior surface of the body. It forms most of the orbital floor and features the infraorbital groove that leads into the infraorbital canal.
• The nasal surface forms a part of the lateral wall of the nasal cavity and features a large opening called the maxillary hiatus that leads into the maxillary sinus.
• The infratemporal surface is the posterior surface of the maxilla. It presents the maxillary tuberosity that contains small openings called the alveolar foramina. The alveolar foramina lead into the alveolar canals.

Frontal process

The frontal process is the superior extension of the maxilla. It projects upward, medially and slightly backward and articulates with the frontal bone.

This process features the lacrimal groove - a vertical groove located on the posterior aspect of it. 

Zygomatic process

The zygomatic process is the short lateral extension of the maxilla for articulation with the zygomatic bone.

Palatine process

The palatine process is the medial extension of the maxilla. It is shaped like a horizontal plate and forms the largest part of the hard palate. 

It features the opening of the incisive canal named the incisive foramen that can be found on the anterior part of the process.

Alveolar process

The alveolar process is an inferior crested extension of the maxilla. Like the alveolar process of the mandible, it also houses the teeth. 

The curved free margin of the alveolar process is called the alveolar arch. The alveolar arch of the maxilla (as the alveolar arch of the mandible) features the following landmarks:

• Dental alveoli - sockets in the alveolar process in which lie the roots of the teeth;
• Interalveolar septa - bony ridges between adjacent dental alveoli;
• Interradicular septa - bony ridges forming compartments in dental alveoli for the roots of the teeth;
• Alveolar yokes (juga alveolaria) - eminences on the outer surface of the alveolar arch produced by the projections of the dental alveoli.

Sutures

Besides the intermaxillary suture between both fused maxillary bones, the maxillae have two or three more sutures. All of them are located in the palatine process, and two of the sutures form the hard palate. 

• The first suture is a sagittal-oriented median palatine suture that connects both maxillae and horizontal plates of the palatine bones as it extends from the maxillae to the palatine bones. 
• The next suture is a horizontal-oriented transverse palatine suture that separates the palatine processes of the maxillae from the horizontal plates of the palatine bones.
• The third suture - the incisive suture - is not always present. It is situated on the anterior portion of the palatine processes, and it separates the anterior parts of the maxillae, which contain dental alveoli, from the rest of the palatine processes. 

  The maxilla is a bone which helps to make up the skull. It is specifically located in the mid face, forms the upper jaw, separates the nasal and oral cavities, and contains the maxillary sinuses (located on each side of the nose.

  One of the maxilla's most important functions is to make up the architecture of our faces and to support the rest of the viscerocranium. It technically consists of two pyramid shaped bones that are fused together in the middle.

  The maxilla houses the upper teeth, forms the roof of the mouth (palate), and also the lower portion of the orbit (bones that surround and house the eyes).

  
  

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  Anatomy

  The maxilla is centrally located within the skull and makes up the center of the face. The lower portion of the maxilla is connected to the upper teeth through the alveolar process. The roots of the teeth form grooves that extend up the anterior portion of the maxilla.

  The alveolar process extends posteriorly below the maxillary sinuses and ends in the maxillary tuberosity. The alveolar process also contains channels through which the alveolar arteries, nerves, and periodontal ligaments run.

  The midline area where the two pyramid-shaped bones of the maxilla fuse together via the median maxillary suture is called the palatine process. The palatine process includes the nasal floor and a portion of the hard palate.

  The anterior portion of the hard palate contains the incisive canal through which the nasopalatine nerve and the sphenopalatine artery run. The palatine process also consists of the superior nasal foramina.

  The most lateral portion of the maxilla is called the zygomatic process because it articulates with zygomatic bone and forms the inferior orbital rim (just below the eye). Lateral to the zygomatic process, on the anterior surface of the maxilla, is a depression known as the canine fossa.

  Another depression called the zygomaticoalveolar crest is located below the zygomatic process and just above the alveolar process.

  The portion of the maxilla which articulates with the frontal bone superiorly and the nasal bones medially is referred to as the frontal process. The frontal process forms several important structures including the nasolacrimal groove, the lower center of the forehead (the area in between but just below the eyebrows), and the nasal bridge.

  Sinuses are easily defined as holes in the skull which decrease the weight of the skull. They are filled with air and lined with a mucous membrane. The maxillary sinuses are some of the largest sinuses in the skull. Like the maxillary bone, the maxillary sinuses are pyramid-shaped with the apex extending towards the zygomatic bone.

  Function

  There are multiple functions of the maxilla. It provides critical bone structure to the skull and defines the face, for example. Since it houses the upper teeth and forms a portion of the jaw, the maxilla is necessary for the process of mastication (chewing) and speaking.

  The mucous membrane lining the maxillary sinuses function to warm and humidify the air we breathe and to produce mucus, which functions as an immune defense. The maxillary sinuses can be prone to disease processes including both benign and malignant growths and infections.

  The maxilla forms the floor and lateral wall of the nasal cavity which are also essential for the function of breathing and the humidifcation and warming of air.

  Associated Conditions

  The maxilla can be affected by congenital malformation, injuries, and infections.

  Cleft Palate

  Cleft palate is a condition in which the hard or soft palate does not fuse properly during fetal development, leaving a gap in the roof of the mouth. It is present at birth and can cause problems with breathing, speaking, and eating, since food and fluids can be inhaled directly into the nasal cavity. It is often caused by a genetic syndrome.

  Facial Fractures

  Any trauma to the face can result in facial fractures involving the maxilla. These fractures are classified by healthcare professionals using the LeFort classification system for maxillary fractures.

  Sinusitis

  Inflammation and infection of the maxillary sinuses is not an uncommon condition and can be more likely to occur in individuals with underlying conditions such as allergies. Symptoms may include facial pain, congestion, and a runny nose.

  Depending on the underlying cause, treatments may include antibiotics, allergy medications, or even sinus surgery.

  Treatment and Rehabilitation

  Conditions associated with the maxilla are often surgically treated. In the case of cleft palate immediate issues involving the ability to breathe or eat must first be given priority. This sometimes involves the use of breathing tubes, special bottles or feeding tubes.

  Once these problems are adequately addressed the cleft palate can be surgically repaired. Sometimes multiple surgeries are required depending on the extent of the defect. Rehabilitation may include speech therapy or dental care.

  The treatment of any fracture involving the maxilla depends on the extent and nature of the injury. In cases of severe trauma fractures to this part of the face may affect your ability to breathe. In this case, measures must be taken to establish a tracheotomy tube or another means to restore respiration before further evaluation and treatment can proceed.

  Unfortunately, fractures in this area also often affect your ability to eat. If the fracture is small and not extensive it may heal in time with rest, a soft diet, and pain medication. Larger more extensive fractures of the maxilla may need to be surgically repaired, especially if trauma to surrounding nerves or blood vessels has been sustained.

  Inflammation or infection of the maxillary sinuses (sinusitis) can be acute or chronic in nature. Acute sinusitis usually resolves within days to a few weeks while chronic sinusitis persists sometimes for months or even longer.

  The sinus cavities can become infected with bacteria or other germs like fungi. In the case of a bacterial infection, antibiotics are necessary. Allergic conditions can cause persistent inflammation and swelling of the sinuses and in some cases leads to abnormal growths inside of the sinus cavities called polyps which require surgical removal.

  Common treatments for sinusitis are measures to control underlying allergies and inflammation, such as antihistamines, and sometimes surgery.

  What make up the upper and lower jawbones?

  The mandible and clavicle make up the upper and lower jawbones. BONUS: What are the 4 functions of the skeletal system? Supports the body by providing a framework, Protects the internal organs, Store minerals, and Makes blood cells in the blood marrow.

  What bones form the lower jaw?

  The mandible forms the lower jaw and holds the lower teeth in place. It articulates with the left and right temporal bones at the temporomandibular joints.

  Which bones form the upper jaw and hard palate?

  Each of the following facial bones are paired: the maxillae form the upper jaw and front of the hard palate; the zygomatic bones form the cheeks; the nasal bones form the bridge of the nose; the lacrimal bones form part of the orbit, or eye socket; the palatine bones form the rear of the hard palate and the inferior ...

  What is the origin of the upper jaw?

  The maxilla (plural: 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.