The upper jaw is primarily known as the maxilla. This complex structure plays a central role in facial anatomy, serving as more than just a support for teeth. It is a fixed bone that integrates with various other bones of the skull, forming the facial skeleton.
The Maxilla and Its Role
The maxilla consists of two irregularly shaped bones that fuse at the midline, just below the nose. This fusion occurs at a seam called the intermaxillary suture. Each maxilla is pyramidal in shape and contains a body and four distinct processes: the alveolar, frontal, zygomatic, and palatine. These processes extend from the main body of the bone.
The maxilla occupies a central position within the midface, providing the bony framework that supports the upper teeth. Due to its extensive connections with nearly all other facial bones (excluding the mandible), the maxilla is often called the “keystone bone” of the face, anchoring and integrating surrounding skeletal elements.
Associated Bones and Structures
While the maxilla is the predominant bone of the upper jaw, it articulates with numerous other bones. These articulations include connections with the frontal bone superiorly, the zygomatic bones laterally, and the palatine bones posteriorly. The zygomatic bones, commonly known as cheekbones, attach to the maxilla, helping to define facial contours.
Other bones, such as the nasal bones, lacrimal bones, ethmoid bone, and sphenoid bone, also connect with the maxilla, contributing to the framework of the eye sockets and nasal cavity. The palatine bones, in particular, join with the palatine processes of the maxilla to form the hard palate, which is the bony roof of the mouth. This intricate network of connections ensures the stability and multifaceted function of the upper jaw unit.
Functions of the Upper Jaw
The upper jaw, composed primarily of the maxilla and its associated bones, performs several important functions. One of its main roles is to provide stable support for the upper teeth, which are embedded within its alveolar process. This support is fundamental for mastication, the process of biting and chewing food, which initiates digestion. The strength and alignment of the upper jaw allow for effective grinding and tearing of food.
Beyond its role in eating, the upper jaw significantly contributes to the overall structure and aesthetics of the human face. It helps define the shape of the midface and supports the nose, influencing facial symmetry and appearance. The maxilla also plays an important part in speech articulation, working in conjunction with the tongue and lower jaw to produce clear sounds. Additionally, the maxilla forms parts of the floor of the eye sockets and the lateral walls and floor of the nasal cavity, housing the maxillary sinuses, which contribute to voice resonance and lighten the skull.