The palate is the roof of the mouth that separates the oral and nasal cavities as well as the nasopharynx. It is arched and lined with oral mucosa, which has mucus producing glands on it known as the palatine glands. There are two parts to the palate – hard and soft. The hard palate lies more anteriorly (in front) while the soft palate lies posterior to it (at the back).
The hard palate is the fixed anterior two-thirds of the palate that is formed by the palatal processes of the maxillae and horizontal plates of the palantine bones. It is arched (concave) and creates a vault within the oral cavity that is mostly filled by the tongue. The depression running on the midline of the hard palate is known as the incisive fossa. Numerous canals allows the nasopalatine nerves to pass through from the nose. Other foramina allow for the entry of the greater and lesser palatine nerves and vessels.
The soft palate is the flexible, posterior one-third of the palate from which the uvula hangs. It is largely muscular and has no bone in it. It has a thicker aponeurotic part anteriorly which attaches to the posterior part of the hard palate. The posterior part of the soft palate is thinner and composed mainly of muscle.
There are five muscles of the soft palate :
- Tensor veli palatini
- Levator veli palatini
- Musculus uvulae
All of these muscles are innervated by the pharyngeal nerve plexus (pharyngeal branch of vagus nerve CN X), except for the tensor veli palatini which is supplied by the medial pteyrgoid nerve via the otic ganlion.
These muscles are able to move the soft palate in different positions to perform various functions. When the soft palate is raised superiorly, it blocks the nasopharynx thereby preventing food and drink that are passing into the pharynx from entering the nasal cavity. When it moves inferiorly, it block the passage into the oral cavity so that air passing out of the lungs passes out through the nose. By tensing the muscles during eating, food can be compressed and pushed down into the throat when swallowing.
Blood Supply to the Palate
Arterial blood is supplied via the greater and lesser palatine arteries. The veins of the palate join the pterygoid venous plexus.
Nerve Supply to the Palate
Branches from the pterygopalatine ganglion (branches of maxillary nerve) supplies the sensory innervation to the palate. Nasopalatine and greater palatine nerves supply the hard palate while the lesser palatine nerves supply the soft palate.