Dominic Stone
The maxilla is the most important bone of the midface in vertebrates, including humans. It is formed from the fusion of two maxillary bones and serves as the upper jaw, separating the nasal and oral cavities. The maxilla also contains the maxillary sinus, which is the largest paranasal sinus, and provides structural support to the viscerocranium. It is a central bone that can fracture through various accidents, most commonly Le Fort fractures, which are subclassified into three types. The maxilla houses the upper dentition in its alveolar process, which is an inferior extension of the maxilla with a porous structure.
| Characteristics | Values |
|---|---|
| Definition | The maxilla is the upper fixed bone of the jaw formed from the fusion of two maxillary bones. |
| Structure | The maxilla is the most important bone of the midface. It has a central location and provides structural support to the viscerocranium. |
| Function | The maxilla has functional and aesthetic significance as it has a fundamental role in facial architecture, separates the nasal and oral cavities, forms the upper jaw, and contains the maxillary sinus. |
| Shape | The maxilla is pyramid-shaped. |
| Surfaces | The maxilla has an orbital, a nasal, an infratemporal, and a facial surface. |
| Processes | The maxilla consists of four basic processes: frontal, ethmoid, nasal, and zygomatic. |
| Alveolar Process | The alveolar process is an inferior extension of the maxilla with a porous structure. It forms the maxillary dental arch containing eight cavities that hold the upper teeth. |
| Maxillary Sinus | The maxillary sinus is the largest paranasal sinus, with an approximate volume of 15 mL in adults. It has a pyramidal shape and its size increases during development. |
| Neurovascular Supply | The maxilla has a rich neurovascular supply. The maxillary nerve and its branches, such as the infraorbital nerve, provide sensory innervation to the surrounding areas. |
| Fractures | Maxilla fractures are a form of facial fracture that can occur due to various accidents or trauma. Le Fort fractures are a common classification of maxilla fractures, which can result in the detachment of the alveolar process and mobility of the upper jaw. |
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What You'll Learn
The maxilla is the most important bone of the midface
The maxilla, or upper jaw, is the most important bone of the midface. It is a vital structure of the viscerocranium, a part of the skull that includes bones such as the mandible, frontal bone, nasal bones, and zygoma. The maxilla has a central location and provides structural support to the viscerocranium, contributing to facial architecture.
The maxilla has a functional and aesthetic role. It separates the nasal and oral cavities, forming the roof of the mouth and the floor and lateral wall of the nasal cavity. It also houses the upper dentition in its alveolar process, a horizontal portion of the maxilla that holds the tooth roots. The maxilla is also involved in the formation of the orbit, or eye socket, and the palate, and plays an important role in mastication and communication.
The maxilla is made up of five major parts: the body and four projections named processes (frontal, zygomatic, palatine, and alveolar). The body of the maxilla is the largest part of the bone and is shaped like a pyramid. It contributes to the anterior margin and floor of the bony orbit, the anterior wall of the nasal cavity, and the inferior part of the infratemporal fossa. The frontal process has a vertical ridge that forms the medial border of the orbit, and it plays a vital role in forming the lateral boundary of the nasal cavity and contributing to the stability of the nasal bridge.
The zygomatic process of the maxilla grows laterally and meets the zygomatic bone, forming much of the cheek and the lateral portion of the inferior orbital rim. The palatine process is a horizontal extension on the medial side of the bone that constitutes the roof of the mouth and the floor of the nasal cavity. Together with the palatine bone, it forms the hard palate. The alveolar process is an inferior extension of the maxilla with a porous structure that forms the maxillary dental arch, containing eight cavities where the upper teeth are held.
The maxilla is susceptible to various types of fractures, most commonly Le Fort fractures, which can result in the detachment of the alveolar process from the maxilla, leaving the patient with a mobile upper jaw. Le Fort II fractures are pyramidal in shape and involve the midface, while Le Fort III fractures result in the complete separation of the viscerocranium from the neurocranium, causing the entire face to hang by the facial tissues.
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It is formed from the fusion of two maxillary bones
The maxilla is a critical bone in the midface of vertebrates, formed from the fusion of two maxillary bones. This fusion occurs at the intermaxillary suture, a vertical line running from the nasal septum to between the two middle front teeth. The maxilla is sometimes considered a single bone and sometimes as two bones, depending on the source. This is because the fusion occurs relatively early in fetal development, around the age of two years.
The maxilla is an irregularly shaped bone with four basic processes and four surfaces: frontal, zygomatic, alveolar, and palatine. It is the second-largest facial bone and is located in the mid-face, extending approximately one-third of the way along each cheek. The maxilla articulates with nine bones: frontal, ethmoid, nasal, zygomatic, lacrimal, palatine, vomer, inferior nasal concha, and the maxilla of the other side.
The maxilla serves several important functions. It houses the upper dentition in its alveolar process, forming the roof of the oral cavity and the floor of the nose and lateral wall of the nasal cavity. The maxilla also contains the maxillary sinus, the largest paranasal sinus, which has an approximate volume of 15 mL in adults. The maxilla is the only bone that has no border with another facial bone.
The fusion of the two maxillary bones is critical for maintaining facial structure and function. This fusion creates the anterior part of the hard palate, which is essential for proper feeding and speech. It also supports the upper teeth, ensuring alignment and stability. Improper fusion of the maxillary bones during development can lead to conditions such as cleft palate, affecting eating and speech abilities.
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It provides structural support to the viscerocranium
The maxilla is the most important bone of the midface. It has a central location and provides structural support to the viscerocranium. The maxilla is a paired bone, with two maxillae uniting with each other at the intermaxillary suture. The maxilla is the upper fixed 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. The maxilla is the critical structure of the inferior orbital rim and forms an important component of the orbital floor. It forms the roof of the oral cavity and the floor of the nose and lateral wall of the nasal cavity.
The maxilla serves as a site of origin/insertion of many muscle groups, including muscles of facial expression, muscles of the velar complex, and the inferior oblique muscle, together with some fibres of origin of the lateral and medial pterygoid muscles. The maxilla also houses the upper dentition in its alveolar process, a horizontal portion of the maxilla that holds the tooth roots. The alveolar process of the maxillae holds the upper teeth and is referred to as the maxillary arch. The maxillary sinus is predominantly contained within the maxilla in the majority of people.
The maxillary sinus is the largest paranasal sinus, with an approximate volume of 15 mL in adults. It has a pyramidal shape, with the base being the medial wall of the sinus, which faces the lateral nasal wall, and its apex situated laterally towards the zygomatic arch. The sinus roof forms part of the orbital floor. It contains the infraorbital canal, which carries the infraorbital neurovascular bundle, exiting through the infraorbital foramen. The infraorbital groove is found at the posterior part of the orbital surface of the maxilla and transmits the infraorbital nerve and vessels. The infraorbital canal opens as a foramen below the margin of the orbit.
The maxilla has functional and aesthetic significance, playing a fundamental role in facial architecture. It separates the nasal and oral cavities and forms the upper jaw. A maxilla fracture is a form of facial fracture, often the result of facial trauma such as violence, falls, or automobile accidents. These fractures are classified according to the Le Fort classification, with Le Fort III fracture involving the separation of the viscerocranium from the neurocranium.
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It contains the maxillary sinus
The maxillary muscles are those that are involved in mastication (chewing). They include the masseter, temporalis, and pterygoid muscles. These muscles work together to elevate, retract and protrude the mandible (lower jaw), enabling us to chew food.
Now, on to the topic of the maxillary sinus, which is closely related to the maxillary muscles and structures in this region.
The Maxillary Sinus:
The maxilla is a crucial bone in the midface, providing structural support and contributing to facial architecture. It forms the upper jaw, separates the nasal and oral cavities, and contains the maxillary sinus. The maxillary sinus is a paranasal sinus, meaning it is located near the nasal cavity. Specifically, it is situated within the maxilla bone, which houses the upper dentition (teeth).
The maxillary sinus is the largest paranasal sinus in adults, with an average volume of 15 mL. It has a pyramidal shape, with its base formed by the medial wall, which faces the lateral nasal wall. The apex of the sinus is positioned laterally towards the zygomatic arch. The roof of the sinus is also referred to as the floor of the orbit (eye socket).
Anatomy and Function:
The maxillary sinus has a rich neurovascular supply. The maxillary nerve, with its various branches, plays a key role in providing sensory innervation to the sinus and surrounding structures. The infraorbital nerve and vessels pass through the infraorbital canal, which is located within the sinus. The sinus is lined with mucoperiosteum, a membranous lining that includes cilia and mucus-producing cells.
The function of the maxillary sinus, like other paranasal sinuses, is multifaceted. It contributes to the resonance of the voice, humidifies and filters the air we breathe, and reduces the weight of the skull. Additionally, the sinus may serve as a reservoir for inflammatory cells, which can aid in immune responses.
Clinical Considerations:
The maxillary sinus is clinically significant due to its proximity to the teeth and other structures. Maxillary sinusitis, an inflammation of the sinus, is a common condition with symptoms such as sinus pain, nasal congestion, thick nasal discharge, and reduced sense of smell and taste. Allergies, nasal polyps, deviated septum, and dental infections can contribute to sinusitis. Treatment options include decongestants, nasal corticosteroids, antibiotics, pain relievers, and saline nasal irrigation. In severe cases, functional endoscopic sinus surgery may be recommended to improve drainage.
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It serves as a site of origin for many muscle groups
The maxilla is the upper fixed bone of the jaw in vertebrates, formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw.
The maxilla is the most important bone of the midface. It has a central location and provides structural support to the viscerocranium. It has functional and aesthetic significance as it has a fundamental role in facial architecture, separates the nasal and oral cavities, forms the upper jaw, and contains the maxillary sinus. The maxillary sinus is the largest paranasal sinus, with an approximate volume of 15 mL in adults. It has a pyramidal shape, with its base being the medial wall of the sinus, which faces the lateral nasal wall, and its apex situated laterally towards the zygomatic arch.
The maxilla serves as a site of origin for many muscle groups, including muscles of facial expression, muscles of the velar complex, and the inferior oblique muscle, together with some fibres of origin of the lateral and medial pterygoid muscles. The maxilla houses the upper dentition in its alveolar process, which is an inferior extension of the maxilla with a porous structure. The alveolar process forms the maxillary dental arch, containing eight cavities where the upper teeth are held. The alveolar process of the maxillae holds the upper teeth and is referred to as the maxillary arch.
The maxilla is supplied by the maxillary nerve, which provides sensory innervation to the lower eyelid, nose, cheek, and upper lip. The maxillary artery is the predominant blood supply to the maxilla, although there is a rich vascular anastomosis between other vascular networks and the maxilla.
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Frequently asked questions
The maxilla is the upper fixed bone of the jaw in vertebrates, formed from the fusion of two maxillary bones.
The maxilla has a central location and provides structural support to the viscerocranium. It also serves as a site of origin/insertion of many muscle groups.
The maxillary sinus is the largest paranasal sinus, with an approximate volume of 15 mL in adults. It is contained within the maxilla in the majority of people.
The maxillary nerve is a direct extension of the infraorbital nerve, which courses anteriorly through the infraorbital canal. It provides sensory innervation to the lower eyelid, nose, cheek, and upper lip.
