Palatine Bone
Os Palatinum
location_on Posterior hard palate and lateral nasal cavity wall
The palatine bone is an L-shaped bone consisting of horizontal and perpendicular plates that form the posterior quarter of the hard palate and part of the nasal cavity floor and lateral wall. It also contributes to the orbital floor and pterygopalatine fossa. Despite its small size, it articulates with six bones and transmits the greater and lesser palatine nerves and vessels.
Key Anatomical Features
- Horizontal plate forms the posterior quarter of the hard palate
- Perpendicular plate forms part of the lateral nasal wall and medial wall of the pterygopalatine fossa
- Pyramidal process fills the gap between the pterygoid plates of the sphenoid
- Orbital process contributes a small portion to the orbital floor
- Greater and lesser palatine foramina transmit the palatine nerves and vessels
Muscle Attachments
| Muscle | Attachment | Action |
|---|---|---|
| Tensor veli palatini | Horizontal plate via palatine aponeurosis | Tenses the soft palate and opens the auditory tube |
| Musculus uvulae | Posterior nasal spine of palatine bone | Elevates the uvula |
| Palatoglossus | Palatine aponeurosis on horizontal plate | Elevates the tongue and depresses the soft palate |
| Medial pterygoid (partial) | Pyramidal process | Elevates the mandible |
Joints and Articulations
| Joint | Type | Connects to |
|---|---|---|
| Palatomaxillary suture | Fibrous suture | Maxilla |
| Median palatine suture (posterior) | Fibrous suture | Opposite palatine bone |
| Palatosphenoid junction | Fibrous suture | Pterygoid plates of sphenoid |
Common Pathologies
Cleft palate (posterior)
Failure of the palatine bones to fuse in the midline results in a posterior cleft palate, causing feeding difficulties and speech problems.
Torus palatinus
Benign bony growth on the midline of the hard palate, present in up to 20% of the population. Usually asymptomatic but may interfere with denture fitting.
Greater palatine nerve block complications
The greater palatine foramen in the palatine bone is the target for nerve block in dental procedures. Complications include hematoma and inadvertent injection into the nasal cavity.
Clinical Relevance
The greater palatine foramen is a critical landmark for dental anesthesia, located at the junction of the hard palate and alveolar process opposite the second or third molar. The pterygopalatine fossa behind the palatine bone contains the maxillary nerve, pterygopalatine ganglion, and the terminal branches of the maxillary artery, making it a gateway for spread of infection or tumor from the oral or nasal cavities to the orbit and cranial fossa.
Development and Ossification
The palatine bone ossifies intramembranously from a single center appearing around the 8th fetal week in the perpendicular plate. The horizontal plates fuse in the midline at the median palatine suture. Cleft palate results from failure of this fusion process.
Did You Know?
- The palatine bone forms only the back quarter of the hard palate; the maxillae form the front three-quarters
- Torus palatinus (a bony growth on the palate) is twice as common in women as men and varies significantly between ethnic groups
- The pterygopalatine fossa behind the palatine bone is sometimes called the crossroads of the face because so many structures pass through it
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