Palate

The palate (Latin: palatum) forms the superior wall of the oral cavity proper, and it is also known as the roof of the mouth. The palate is a part of the digestive system, and it separates the nasal from the oral cavity as it also forms the nasal cavity's inferior wall. The palate has two parts- the hard palate(Latin: palatum durum) anterior and the soft palate posterior (Latin: palatum molle). 

The hard palate forms the bony roof part of the oral cavity, covered by the periosteum and firmly fused with the mucosa. The soft palate is the hard palate's continuation, and opposite it, the soft palate doesn't contain a skeleton made by bones, but it is the palate's muscular part. Hard and soft palate has an essential role in digestion, feeding, swallowing, breathing and articulation, and speech formation.

Hard palate anatomy

The hard palate is the immobile and horizontal oriented anterior two-thirds of the palate. The hard palate has two surfacesthe oral surface facing the oral cavity and the nasal one facing the nasal cavity. Anteriorly and lateral, it borders with the maxillary teeth but posteriorly with the soft palate. 

Bone frame and sutures

The hard palate's bony base forms two palatine bones' horizontal plates posterior and two palatine processes of maxilla anterior covered by mucosa. Both parts connect sagittal oriented median suture in the midline and frontal oriented transverse palatine suture located between the anterior two-thirds and posterior one-third of the hard palate. Most of the hard palate forms the palatine processes of the maxilla, around two-thirds. The hard palate divides the oral cavity from the nasal cavity as it also creates the nasal cavity's inferior wall. 

Hard palate divides into two parts- the primary palate and the secondary. Both parts divide incisive suture in the form of the letter "V." Incisive suture starts between both side's lateral incisor and canine teeth, and both suture lines connect in the place behind the incisive foramen. The primary hard palate is only a small part located anterior to the incisive foramen. The secondary palate is the rest of the hard palate, posterior to the primary and anterior to the soft palate.

Openings and landmarks

In the anterior part, the hard palate's mucosa forms several transverse directions going palatine rugae (ridges) covering the alveolar ridge. 

Behind the two central incisors in the middle, locate incisive papilla overlying incisive fossa or foramen and incisive canal

The nasopalatine nerve, the sphenopalatine artery, and terminal branches of the greater palatine artery go through the canal.

Median raphe starts in the midline between central incisors, extending in the soft palate and dividing palate into the right and left sides. Palate-forming bones have several palatine grooves on the surface for palatine vessels. 

The palate has two pairs of foramen on each side in its posterior part. The greater palatine foramen locate in the lateral sides at palatine bone's horizontal plates and palatine processes of maxilla meeting place, a little bit posterior to it and close to the third molar teeth. It transmits the greater palatine nerves and blood vessels

The lesser palatine foramen locate behind greater palatine foramen in the pyramidal process. It transmits the lesser palatine nerves.

Soft palate anatomy

The soft palate, also known as the muscular palate, is located posterior to the hard palate and is its continuation. It forms the palate's posterior one-third. It is very mobile, elastic, and durable. The soft palate has two surfaces- the oral facing the oral cavity and the nasal facing the nasopharynxAnteriorly and superiorly, it borders with the hard palate. While posteriorly and inferiorly, it has a free margin extending in the oropharynx. On the sides, it has a border with the root of the tongue and oropharynx lateral walls.

Soft palate landmarks

The anterior soft palate's part has a horizontal direction, while the posterior part hangs down in a vertical order facing the tongue. It is called the velum palatinum. It ends with a free edge having an elongated growth in the middle, called the uvulaUvula helps to separate the oropharynx from the nasopharynx. 

The uvula's lateral sides form two arches connecting the tongue and pharynx to the soft palate. The anterior arch is palatoglossal. It has a more ventral direction, ending in the tongue's root. The posterior is the palatopharyngeal arch, located dorsally from the previous one and ending in the pharynx's lateral sides. 

Both two arches sometimes are called faucial pillars or pillars of fauces. Because the soft palate's posterior end with the uvula in the middle, and both arches form the oropharyngeal isthmus superior and lateral parts. Oropharyngeal isthmus or isthmus of fauces is an opening connecting the oral cavity with the pharynx's mouth part. 

Between both arches on both sides locate tonsillar fossa containing lymphoid tissue aggregation- the palatine tonsil. 

Muscular palate 

The soft palate mainly forms the palatine aponeurosis, skeletal muscles, and mucosa. The palatine aponeurosis is a connective tissue plate starting from the palatine bones' posterior edge and continuous in the longitudinal direction across the soft palatine's length. It has a connection with palate muscles, and it forms the base of the soft palate.

Soft palate muscles

The soft palate contains five skeletal muscle pairs having essential roles in swallowing, breathing, and articulation functions. 

Levator veli palatini and tensor veli palatini muscles press the soft palatine to the pharynx's posterior and lateral walls, dividing the pharynx nasal part from the oropharynx. It happens mainly during swallowing, allowing the food from the oral cavity goes next through the oropharynx to the esophagus. 

The palatopharyngeus muscles primary are involved in breathing, but the four remaining muscles in swallowing.

  • Tensor veli palatini originates from the auditory tube's cartilaginous part and the medial pterygoid plate of the sphenoid bone. Muscle fibers insert into the palatine aponeurosis. This muscle stretches and tenses the soft palate and expands the auditory tube during swallowing.
  • Uvulae muscle elevates and shortens the uvula. It starts in palatine aponeurosis and the hard palate's posterior nasal spine and ends in the uvula.
  • Levator veli palatini elevates the soft palate during swallowing. It originates at the external cranial base on the inferior surface of the temporal bones' petrosal part and the auditory tubes' cartilaginous part. Muscle inserts in palatine aponeurosis.
  • Palatoglossus starts in the palatine aponeurosis and goes by the palatoglossal arch until the tongue's root's lateral sides, where it inserts. The muscle narrows the oropharyngeal isthmus and shortens the palatoglossal arch, pulls the soft palate towards the tongue.
  • Palatopharyngeus shortens the palatopharyngeal arch and narrows the oropharyngeal isthmus, tenses the soft palate. Muscle also moves the pharynx in superior and anterior direction during swallowing. Muscle fibers start in palatine aponeurosis and hard palate. They go by the palatopharyngeal arch, ending in the pharynx's lateral sides and the thyroid cartilage's superior border.

Palate microanatomy

Hard palate's mucosa usually has a light pink color, while softs palate has a darker or reddish and a bit yellowish pink color. The palate has two different types of mucosal epithelium. Its nasal cavity's inferior wall forming side and posterior surface of the soft palate's free edge facing the nasopharynx has a respiratory epithelium. It is the continuation of the nasal cavity's mucosa covered by ciliated epithelium. The soft palate's mucosa facing the oral cavity is a continuation of the hard palate's oral epithelium. Palate's epithelium contains minor salivary glands.

Hard palate 

During the mastication, the hard palate's mucosa is subject to mechanical action by various factors. That's why it covers stratified squamous keratinized or partially keratinized epithelium. The epithelium closely fuses with the connective tissueIn the hard palate's anterior part, deep in the connective tissue, locate many fat cells. The hard palate's middle and posterior part contains a considerable amount (around 250) of mixed and mucous salivary glands. In the palate raphe area, the connective tissue layer is thin, and it has a close and strong connection with the periosteum. The nasal cavity's part epithelium is the ciliated pseudostratified columnar, containing mucus-producing goblet cells.

Soft palate

Soft palate contains a significant amount of collagen and elastin fibers. Its oral cavity's part covers stratified squamous non-keratinized epithelium. Usually, children's epithelium contains taste buds in the soft palate part, while adults rarely have them. Connective tissue is very vascular. Soft palate contains mixed and mucous minor salivary glands with a more significant amount in the uvula region. 

The nasopharynx part epithelium is the ciliated pseudostratified columnar, containing mucus-producing goblet cells. Connective tissue contains mixed glands

The uvula part covers the squamous stratified non-keratinized epithelium.

Palate functions

The palate is involved in several physiological processes, mainly helping in digestion, articulation, breathing, and speech formation

The hard palate mostly involves feeding and speech formation, while the soft palate takes part in the swallowing process and providing normal breathing during the swallowing

Hard palate

  • The hard palate also separates the nasal and oral cavities, such as the soft palate. 
  • The hard palate's structure allows it to participate in the mastication process. It withstands mechanical forces during chewing and swallowing and helps to form the food bolus. The palate rugae help to do the chewing and food bolus formation more efficiently. 
  • The hard palate helps to hold the food during further transportation. 
  • It provides slight changes in the oral cavity pressure when the nasal passages are closed, and by that, it ensures the suckling and breastfeeding for newborn babies. 
  • The tongue and hard palate interaction help form certain speech sounds, such as the letter "T" or "D."

Soft palate

  • As the soft palate is moveable and contains many muscles, it is responsible for closing the pharyngeal isthmus. By that, the soft palate separates the oropharynx from the nasopharynx during swallowing. It prevents food and fluid regurgitation into the nasopharynx and airways. 
  • The soft palate also acts similarly during the sneezing as it closes the nasal passage providing the secretion flow only in the oral cavity direction. 
  • The soft palate provides the oral speech sound without nasal sounds by separating the nasal cavity from the oral cavity
  • The soft palate and tongue movements help form speech sounds such as letters "N" and "K."
  • As the palate mostly innervates branches from the vagus nerve, the soft palate's uvula part provides the gag reflex as touching the uvula can cause the reflex and vomiting. So it has a protective function in case of ingesting poisonous substances.
  • The soft palate provides the breathing when the mouth is closed as it doesn't complete the pharyngeal isthmus during the nasal breathing. 
  • Snoring happens because of partial obstruction of the airways caused by gravity, muscle relaxation, and soft palate movements during breathing while sleeping. 

Neurovascular supply

Arterial blood supply

The arterial blood supply for palatine mainly provides two arteries- the ascending and descending palatine arteriesThe first one perfuses only the soft palate, while the second one both palates and the muscles. The descending palatine artery has two branches- the greater and lesser palatine arteries.

Ascending palatine artery is a branch of the facial but descending is from the maxillar one. Both are external carotid artery branches.

The palatine tonsil perfuses the tonsillar artery of the facial artery and the ascending palatine artery (from the facial artery), dorsal lingual artery (from the lingual artery), ascending pharyngeal artery of the external carotid artery, and major palatine artery.

Venous and lymphatic drainage

Venous drainage provides the facial vein, going next to the common facial vein and then to the internal jugular vein. Veins mostly drain to pterygoid and tonsillar venous plexuses.

Lymph from the soft and hard palate mostly drains to deep cervical nodes.

Innervation

The motor innervation for almost all soft palatine muscles provides vagus nerve (CN X) pharyngeal brunch with pharyngeal plexus. The tensor veli palatini muscle innervates the medial pterygoid nerve. It is the trigeminal nerve's mandibular branch (CN V3).

The sensory innervation primarily provides the maxillary branch of the trigeminal nerve (CN V2)

The palate innervates nerves from the pterygopalatine ganglion, the greater and lesser palatine nerves, and the nasopalatine nerve. The greater palatine nerve mostly innervates the hard palate, while the lesser palatine nerve- the soft palate.

The palate tonsilla, palatoglossal and palatopharyngeal arches innervate tonsillar nerves from the glossopharyngeal nerve (CN IX).

The greater petrosal nerve from the facial nerve (CN VII), together with the lesser palatine nerve, carries information about taste buds' taste sensations.

Cleft palate

The cleft palate is among the most orofacial congenital disabilities, mostly affecting the hard palate, but it can also involve the soft palate. It happens during the embryological development around the sixth to the ninth week when palatine processes of the maxilla and palatine bone's horizontal plates don't fuse properly together, leaving a gap in the middle between them. It can happen partially or entirely. This condition has an association with the cleft lip- an opening in the lip. The cleft palate can be an isolated disorder, but it can also be associated with other genetic diseases such as Edwards syndrome (18 chromosome trisomy). Isolated cleft palate most often affects the girls, but cleft lip- boys.

Babies presenting cleft palate have visible facial deformities and have problems with proper breathing, feeding, and speech, resulting in malnutrition and growth retardationIf untreated, later they experience difficulties with speech formation. Children with cleft palate can have recurrent middle ear infections and hearing problems, and teeth issues. 

Risk factors

The risk factors for cleft palate are often unidentified, but some linked relations are probably causing the condition. Cleft palate is a multifactorial disorder meaning it causes changes in genes and the mother's environmental factors such as medications, eating, and drinking habits. The chance for a baby having the cleft palate increases:

  • family history of cleft palate or lip,
  • smoking during the pregnancy,
  • drinking during the pregnancy,
  • medication usage during pregnancy, most often the condition is caused by medication used to treat epilepsy or folic acid antagonists (methotrexate),
  • diabetes,
  • obesity during pregnancy.

Variations

The cleft palate can present as unilateral, affecting just one side of the palate or bilateral. There are three types of cleft palate: complete, incomplete, and submucosal cleft palate

In the first variation, the disorder affects the hard and soft palate and also the uvula. 

The incomplete variation presents with secondary palate's clefting in the hard palate. 

In the submucosal variations, the mucosa is intact, but the underlying muscle part has a defect.

Diagnosis and treatment

The cleft palate can diagnose before the child is born by ultrasound or after the birth by physical examination

Treatment depends on the cleft palate's variation and severity, other presenting disorders. Cleft palate usually is treated between six to twelve months. Healthcare professionals recommend repairing the defect within the first 18 months. Most children born with cleft palate and successful surgery performed won't have any issues later in their life

Summary on palate

What is a palate?

The palate is a part of the digestive system. It separates the nasal from the oral cavity as it forms the nasal cavity's inferior and the oral cavity's superior wall. It has two parts. The anterior is the bony part- hard palate, while the posterior is the muscular part- the soft palate.

What are the parts of the palate?

The palate consists of two parts- the hard and soft palate.

What is the roof of the mouth called?

The roof of the mouth forms the hard and soft palate, so it is called the palate.

What is the soft palate?

The soft palate is the hard palate's continuation. It is the posterior part of the palate forming the mouth's roof. The soft palate doesn't contain a skeleton made by bones, but it is the palate's muscular part. It has two parts- the horizontal extending from the hard palate and the vertical going free edge with a uvula in the middle.

What is the hard palate?

The hard palate forms the bony roof part of the oral cavity, covered the periosteum, and firmly fused with the mucosa. It makes the palate's anterior two-thirds.

What are the two palatine bones?

Hard palate forms the palatine process of the maxilla and horizontal plate of the palatine bone.

Does palate contain taste buds?

Yes, it does. Soft palate epithelium in the oral cavity part can contain taste buds. Usually, children's epithelium has them, and rarely can they be detected in adults.

What is the function of the hard palate?

The hard palate mostly helps in the mastications, feeding, bolus making process, suckling, and speech formation.

Is the roof of the mouth smooth?

No, the roof of the mouth is not smooth. Its anterior part contains several palatine rugae.

What are the palatine muscles?

The palate has five pairs of muscles- levator veli palatini, tensor veli palatini, palatoglossus, palatopharyngeus, and the uvulae muscles.

Which nerve innervates the palatine muscles?

The motor innervation for almost all soft palatine muscles provides vagus nerve (CN X) pharyngeal brunch with pharyngeal plexus. The tensor veli palatini muscle innervates the medial pterygoid nerve. It is the trigeminal nerve's mandibular branch (CN V3).

What is the healthy color of the roof of the mouth?

The roof of the mouth typically has a pink color.

What is the function of the palate?

The palate's primary functions are feeding, swallowing, breathing, articulation, and speech formation.

What is cleft palate?

The cleft palate is among the most orofacial congenital disabilities, mostly affecting the hard palate, but it can also involve the soft palate. It happens during the embryological development around the sixth to the ninth week when palatine processes of the maxilla and palatine bone's horizontal plates don't fuse properly together, leaving a gap in the middle between them.

What causes a cleft palate during pregnancy?

The risk factors for cleft palate are often unidentified, but some linked relations are probably causing the condition. Cleft palate is a multifactorial disorder. It causes changes in genes and the mother's environmental factors such as medications, eating, and drinking habits, for example, consuming alcohol and smoking during the pregnancy.

Can you fix a cleft palate?

Yes, cleft palate is easily fixable by surgery after birth in the first 18 months.

At what age is the cleft palate repair?

Healthcare professionals recommend fixing cleft palate from six to twelve months, usually done by the first 18 months.

What happens if the cleft palate is left untreated?

Babies presenting cleft palate have visible facial deformities and have problems with proper breathing, feeding, and speech, resulting in malnutrition and growth retardation. If untreated, later they experience difficulties with speech formation. Children with cleft palate can have recurrent middle ear infections and hearing problems, and teeth issues.