Palatine bone

General structure and position

Anatomically, the palatine bone (Os palatinum) is a paired formation. It is located in the deep regions of the facial skeleton and features a complex spatial organization. The bone enters into close topographic relationships with the maxilla anteriorly, the sphenoid bone posteriorly, and also takes a direct part in the formation of the bony walls of the nasal cavity.

Basically, the bone consists of two main elements located at an angle to each other:

• Perpendicular plate (Lamina perpendicularis);
• Horizontal plate (Lamina horizontalis).

Perpendicular plate

The perpendicular plate (Lamina perpendicularis) is oriented vertically. On an intact skull, this structure is particularly convenient to demonstrate and study on the lateral wall of the nasal cavity when viewed from the side of the choanae.

The plate has two pronounced surfaces, each of which bears important anatomical landmarks:

1. Lateral surface (maxillary) — Facies maxillaris. It faces outward, towards the pterygopalatine fossa. A characteristic feature of this surface is the vertically running greater palatine sulcus (Sulcus palatinus major). When joined with the corresponding sulcus on the maxilla, it closes to form the complete greater palatine canal.
2. Medial surface (nasal) — Facies nasalis. This side faces directly into the nasal cavity. It features two prominent horizontal bone ridges: the ethmoidal crest (Crista ethmoidalis) and, located below it, the conchal crest (Crista conchalis).

Processes of the perpendicular plate

Several important processes extend from the perpendicular plate, ensuring connection with neighboring bones.

In the upper part of the plate, two processes become distinct:

• Orbital process (Processus orbitalis) — directed forward and upward, takes part in the formation of the medial wall of the orbit.
• Sphenoidal process (Processus sphenoidalis) — directed backward, tightly adheres to the body of the sphenoid bone.

Between these two upper processes, a deep sphenopalatine notch (Incisura sphenopalatina) is formed. On the intact skull, it serves as an essential pathway for blood vessels and nerve trunks to pass into the nasal cavity.

Posteriorly and inferiorly, the perpendicular plate massively continues into the pyramidal process (Processus pyramidalis). It wedges between the plates of the pterygoid process of the sphenoid bone, thereby completing the pterygoid fossa (Fossa pterygoidea). Directly in the region of the pyramidal process, one can find the lesser palatine foramina (Foramina palatina minora), which lead into the lesser palatine canals (Canales palatini minores). These small canals internally communicate with the main greater palatine canal.

Horizontal plate

The horizontal plate (Lamina horizontalis) is located in the horizontal plane and performs the function of supplementing the bony hard palate in its posterior sections.

It also has two surfaces with characteristic relief:

• Superior (nasal) surface — Facies nasalis. It faces the floor of the nasal cavity. It features the nasal crest (Crista nasalis), which extends in a sagittal direction and ends at its posterior extremity with a sharp projection — the posterior nasal spine (Spina nasalis posterior).
• Inferior (palatine) surface — Facies palatina. It faces the oral cavity. The palatine crest (Crista palatina) runs distinctly along its midline.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Topography of the pterygopalatine fossa and its communication with the nasal cavity.
• Detailed formation of the bony hard palate.
• Structural features of the lateral wall of the nasal cavity and choanae.
• Course of vessels and nerves through the greater and lesser palatine canals.

Other topics in the "Skull" section

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