Palatine Bone: Structure, Function & Diseases

The palatine bone is a component of the facial skull and, together with the maxilla, contributes to the separation of the nasal and oral cavities. It forms during embryonic development as palatine processes grow together from the maxillary ridges. Disruptions in this process can affect the separation of the nasal cavity and oral cavity.

What is the palatine bone?

The palatine bone, also known as the os palatinum, represents a bone of the facial skull responsible for separating the nasal cavity from the oral cavity. It consists of both a horizontal and a vertical plate. The horizontal plate (lamina horizontalis), together with the ploughshare bone (vomer), forms the palate, while the vertical plate (lamina perpendicularis), together with the maxilla bone (maxilla) and the sphenoid bone, represents the pterygopalatine fossa. The pterygopalatine fossa contains nerves and blood vessels that supply the maxilla. In addition to separating the nasal and pharyngeal cavities, the palatine bone also helps support the posterior portion of the hard palate. The hard palate consists of fused bony plates of the horizontal bony processes of the maxillary bone and the palatine bone.

Anatomy and structure

The palatine bone represents palatine processes that develop from the maxillary ridges. They move toward each other during embryonic growth and grow together forming a suture. In the process, the hard palate closes, separating the nasal and oral cavities. The choanal opening joins the posterior end of the hard palate. The choana represents the paired opening of the nasal cavity into the pharyngeal cavity. The ploughbone separates the two choanae openings. This part of the palate is also called the lamina horizontalis. In this context, the lamina horizontalis is a part of the palatine bone. The other part of the palatine bone, the lamina perpendicularis, represents its vertical part. Together with the maxillary bone and the sphenoid bone, it forms the pterygopalatine fossa. The pterygopalatine fossa contains the nerve cords of the maxillary nerve and the pterygopalatine ganglion as well as the branches of the maxillary artery. The maxillary nerve supplies the lacrimal glands, gums, upper incisors, and palatal mucosa, among others, and is purely sensitive. The pterygopalatine ganglion is responsible for the secretory activity of the lacrimal, palatine, nasal, and pharyngeal glands, as well as the work of the blood vessels of the face and brain. The maxillary artery is the maxillary artery and is the continuation of the carotid artery.

Function and tasks

The main function of the palatine bone is to separate the nasal and pharyngeal cavities. This allows food intake and breathing to proceed undisturbed by each other. Perfect middle ear ventilation is ensured so that the body can effectively counter the outbreak of ear infections. In general, separate work of the oral and nasal cavities is necessary for a good defense against infections. Furthermore, the palatine bone also has supporting functions for the posterior part of the palate. As part of the skull, it thus helps to protect the brain. At the same time, the palatine bone also contains important passage points for blood vessels and nerve cords that are responsible for supplying important organs in the head area.

Diseases

In connection with the palatine bone, malformations may occur during embryogenesis. In early pregnancy, there is always initially separate development of facial parts that later grow together. Thus, the gill arch develops into nasal bulges and maxillary bulges on both sides, respectively. It is not until the fifth week of pregnancy that the two nasal bulges merge. During this process, the intermaxillary segment is formed. If this process is disturbed, a cleft lip and jaw develops. From the tenth week of pregnancy, the palatal processes (palatine bone) of both maxillary bulges normally fuse, forming the hard and soft palate. If this fusion is not complete, a cleft palate develops. The nasal and pharyngeal cavities do not separate. Both malformations are independent of each other, as they also occur at different stages of development. However, cleft lip and palate often occur together. Colloquially, cleft lip and jaw used to be called harelip and cleft palate was called wolf cleft.However, since these designations were perceived as discriminatory, they are no longer used today. The manifestations of these malformations are manifold. They depend on the stage of pregnancy at which the disorder occurs. There are mild cleft lip and jaw, combinations of cleft lip and jaw with cleft palate, or pure cleft palate. The manifestations of cleft palate can also vary. In the best case, only a cleft is found in the uvula. In the worst case, there is a complete cleft between the solid and soft palate, concealed only by the overlying mucosa. In this case, the nasal and pharyngeal cavities are no longer separated. The causes of cleft lip and palate are not yet fully understood. It is known that in many cases there must be a hereditary component. Thus, familial accumulations of this malformation have been found. However, there are also environmental influences that can lead to cleft lip and palate. These include smoking by the expectant mother, lack of oxygen during pregnancy, alcohol abuse by the mother, radiation effects, and more. The effects of malformations are variable depending on the degree of formation. Thus, isolated cleft lips are not problematic. They can be quickly corrected by surgery. However, cleft palate and cleft lip and palate can lead to a variety of impairments. For example, it is difficult for newborns to eat because food can pass through the cleft into the nasal cavity. Furthermore, there are often respiratory problems because nasal breathing is usually obstructed. Speech problems often occur. Furthermore, frequent ear infections and malocclusion of the teeth occur. Treatment consists of surgical correction, speech enhancement, and psychotherapy.