Palatine bone

At a glance

English

Palatine bone

Latin (TA2)

Os palatinum

System

Bone

Region

Head

Side

Paired, left and right

About the palatine bone

The palatine bones are a pair of small, irregular bones at the rear of the nose, wedged between the maxilla in front and the sphenoid's pterygoid process behind. Seen from behind each looks like a letter L: a horizontal plate forms the rear of the bony palate, and a perpendicular plate rises along the side wall of the nose. Through these plates and their processes a single bone contributes to the walls of the mouth, the nasal cavity and the orbit, and to the pterygopalatine fossa.

The two horizontal plates meet each other in the midline and join the palatine processes of the maxillae in front at the transverse palatine suture, so that the hard palate is roughly three-quarters maxilla and one-quarter palatine. Their free back edge gives attachment to the soft palate, and in the midline they project as the posterior nasal spine. The perpendicular plate is thin and forms part of the lateral wall of the nasal cavity, behind the maxillary sinus, with crests for the inferior and middle conchae.

Three processes add to the shape. The pyramidal process juts back and out from the corner of the L into the gap between the pterygoid plates. At the top of the perpendicular plate sit the orbital process, which reaches the floor of the orbit, and the sphenoidal process, which touches the underside of the sphenoid. The deep notch between them is closed by the sphenoid to form the sphenopalatine foramen, through which the sphenopalatine artery and nerves from the pterygopalatine ganglion enter the nose. In all, each palatine bone touches its partner, the maxilla, the vomer, the inferior nasal concha, the ethmoid and the sphenoid.

The greater palatine foramen opens near the back corner of the hard palate, level with the third molar; it carries the greater palatine nerve and vessels forwards across the palate; just behind it the smaller lesser palatine foramina serve the soft palate and tonsil. Dentists inject local anaesthetic at the greater palatine foramen to numb the back of the palate.

Function and supply

Function

Separates the mouth from the nose at the back of the palate, giving a firm base for the soft palate and letting breathing continue while food is chewed.

Nerve supply

Not innervated as a muscle is; the greater and lesser palatine nerves and nasal branches of the maxillary nerve, relayed through the pterygopalatine ganglion, pass through and along it.

Blood supply

The greater and lesser palatine arteries from the descending palatine branch of the maxillary artery, and nasal branches of the sphenopalatine artery.