The maxillary sinus, also known as the maxillary antrum or the antrum of Highmore, is a large, air-filled cavity located within the maxilla, the upper jaw bone. It is one of the four pairs of paranasal sinuses found in the human skull, along with the frontal, ethmoid, and sphenoid sinuses.
Structure
The maxillary sinus is located within the body of the maxilla, which forms the upper jaw and the roof of the oral cavity. It is a pyramid-shaped cavity that extends from the cheekbone (zygomatic bone) to the upper molars. The sinus has a thin wall that separates it from the oral cavity, and it is lined with a thin layer of mucous membrane.
The maxillary sinus has four walls:
- Anterior wall: This wall is adjacent to the cheekbone and the alveolar process, which holds the upper teeth. The anterior wall is also in close proximity to the infraorbital nerve and the infraorbital artery, which supply blood to the face and the eye.
- Posterior wall: The posterior wall is adjacent to the pterygopalatine fossa, which is a deep indentation in the skull that contains the pterygopalatine ganglion and various other structures.
- Lateral wall: The lateral wall is adjacent to the orbit, which is the bony cavity that houses the eye.
- Medial wall: The medial wall is adjacent to the nasal cavity and the ethmoid sinus. The maxillary sinus communicates with the nasal cavity through the ostium, a small opening in the medial wall.
Location
The maxillary sinus is located within the body of the maxilla, which forms the upper jaw and the roof of the oral cavity. It is located between the cheekbone and the upper molars, and it extends from the cheekbone to the pterygopalatine fossa.
Function
The main function of the maxillary sinus is to moisten and warm the air that we inhale. It is lined with a thin layer of mucous membrane that produces mucus, which helps to humidify the air that we breathe in through the nostrils. The sinus also helps to reduce the weight of the skull by being filled with air, which makes it lighter and easier to move.
In addition, it plays a role in speech and vocalization by resonating sound waves that are produced in the pharynx. It also helps to protect the teeth and the surrounding structures by providing a cushioning effect.
Clinical Significance
The maxillary sinus is prone to a number of conditions and diseases, which can affect its function and cause symptoms such as sinusitis, nasal congestion, and headaches.
- Sinusitis: Sinusitis is an inflammation of the sinus lining, which can be caused by a viral infection, allergies, or the presence of a foreign object in the sinus. It is characterized by symptoms such as nasal congestion, headache, fever, and facial pain.
- Nasal congestion: Nasal congestion is a common condition that is caused by the swelling of the nasal passages, which can be caused by allergies, a cold, or the flu. It is characterized by difficulty breathing through the nose and a feeling of fullness in the sinuses.
- Headaches: Headaches can be caused by a number of factors, including sinusitis, nasal congestion, and other conditions that affect the maxillary sinus. Sinus headaches, in particular, are characterized by pain in the forehead, cheekbones, or upper teeth, and they may be accompanied by other symptoms such as nasal congestion and a sensation of fullness in the sinuses.
- Dental problems: The maxillary sinus can also be affected by dental problems, such as tooth infections or abscesses. These conditions can cause inflammation and swelling of the sinus lining, leading to sinusitis or other problems.
- Cysts and tumors: The maxillary sinus can also be affected by the presence of cysts or tumors, which can cause symptoms such as nasal congestion, facial pain, and difficulty breathing. These conditions may require surgical intervention to remove the growth and restore normal function to the sinus.
