The hard palate is the anterior bony subsection of the palate of the mouth that comprises approximately two thirds of it.
This article will discuss the borders of the hard palate, its function, anatomy and possible pathology.
The anterior portion of the palate is bordered anteriorly and laterally by the maxillary teeth. Superiorly it is covered by the respiratory epithelium of the nasal cavity and inferiorly by the masticatory epithelium of the oral cavity. Posteriorly, the hard palate is connected to the soft palate, which is a purely muscular structure and is bound by an thick tendinous aponeurosis of the tensor veli palatini muscles on both sides, which is known as the aponeurotic plate.
The objective of the hard palate is both feeding and speech. Before modern surgeries were developed, infants with defective palates couldn’t suckle and would often die. It is used to create a vacuum which forces the liquid into the mouth so that it can be ingested. It is also essential, along with the tongue, to create certain phonetic sounds. When a person has a cleft palate for example, they are either unable to pronounce these sounds or they do but with a distinct nasal vibration which makes their diction very unclear.
The hard palate separates the oral and nasal cavities, bordering the oral cavity superiorly and forming the roof of the mouth, and the nasal cavity inferiorly, forming its floor. Its bony structure is comprised of three cranial bones, the maxilla and the paired palatine bones. Anteriorly, the palatine process of the maxilla is situated, covering the area between the two sides of the maxillary dental arch until posteriorly it meets the two horizontal palatine processes, which are fused down the midline, as the the two embryonic palatine shelves of the maxilla.
In the anterior midline, the incisive foramen can be found, which sits just below the incisive papilla that is a fleshy convexity on the palatal mucosa. This foramen transmits the terminal branches of the nasopalatine nerve and the sphenopalatine arteries and veins. It is situated approximately one centimeter behind the medial maxillary incisors.
Posterolaterally, one centimeter medial from the second maxillary molar, the greater and lesser palatine foramina can be found. The greater foramina is seated just anterior to the lesser one. They transmit the greater and lesser palatine nerves and vessels respectively.
Since the palate fused on either side during embryonic development, just posterior to the incisive papilla there is a thick palatine raphe which continues posteriorly along the midline as a remnant, with transverse rugae which are lateral transverse ridges of the mucosa radiating outwards. This plicae are more apparent anteriorly. Deep in the palatal mucosa are hundreds of mucous secreting salivary glands.
A common birth defect that affects the hard palate is known as a cleft palate. This anomaly occurs during embryonic development and the palatine shelves of the maxilla don’t fuse properly, leaving a gap in the hard palate and, in severe cases, a connection between the oral and nasal cavities.
The treatment for this type of deformity is quite extensive and invasive. Usually multiple surgeries are required, along with speech therapy, orthodontic treatment and chronic use of a prosthesis.