Hard Palate
It is a partition between the nasal and oral cavities.
Its anterior two-thirds are formed by the palatine processes of the maxillae; and
its posterior one-third by the horizontal plates of the palatine bones
The anterolateral margins of the palate are continuous with the alveolar arches and gums.
The posterior margin gives attachment to the soft palate.
The superior surface forms the floor of the nose.
The inferior surface forms the roof of the oral cavity.
Blood & Nerve Supply
Arteries: Greater palatine branch of maxillary artery
Veins: Drain into the pterygoid plexus of veins.
Nerves: Greater palatine and nasopalatine branches of the pterygopalatine ganglion suspended by the maxillary nerve.
Lymphatics: The lymphatics drain mostly to the upper deep cervical nodes and partly to the retropharyngeal nodes.
- It is a movable, muscular fold, suspended from the posterior border of the hard palate.
- It separates the nasopharynx from the oropharlmx, and is often looked upon as traffic controller at the crossroads between the food and air passages
- The soft palate has
- two surfaces, anterior and posterior; and
- two borders, superior and inferior.
- The anterior (oral) surface is concave and is marked by a median raphe.
- The posterior surface is convex, and is continuous superiorly with the floor of the nasal cavity.
- The superior border is attached to the posterior border of the hard palate, blending on each side with the pharynx.
- The inferior border is free and bounds the pharyngeal isthmus.
- From its middle, there hangs a conical projection, called the uvula
- From each side of the base of the uvula two curved folds of mucous membrane extend laterally and downwards.
- The anterior fold is called the palatoglossal arch or anterior pillar of fauces.
- It contains the palatoglossus muscle and reaches the side of the tongue at the junction of its oral and pharyngeal parts.
- This fold forms the lateral boundary of the oropharyngeal isthmus or isthmus of fauces.
- The posterior fold is called the palatopharyngeal arch or posterior pillar of fauces.
- It contains the palatopharyngeus muscle.
- It forms the posterior boundary of the tonsillar fossa, and merges inferiorly with the lateral wall of the pharynx.
Structure
• The soft palate is a fold of mucous membrane containing the following parts:
- The palatine aponeurosis which is the flattened tendon of the tensor veli palatini forms the fibrous basis of the palate.
- Near the median plane, the aponeurosis splits to enclose the musculus uvulae.
- The levator veli palatini and the palatopharyngeus lie on the superior surface of the palatine aponeurosis.
- The palatoglossus lies on the inferior or anterior surface of the palatine aponeurosis.
- Numerous mucous glands, and some taste buds are present.
- Muscles of the Soft Palate
They are as follows:
1 Tensor palati (tensor veli palatini).
2 Levator palati (levator veli palatini).
3 Musculus uvulae.
4 Palatoglossus.
5 Palatopharyngeus
• Tensor Veli Palatini
This is a thin, triangular muscle
Origin
a. Lateral side of auditory tube
b. Adjoining part of the base of the skull (greater wing and scaphoid fossa of sphenoid bone)
Insertion
Muscle descends, converges to form a delicate tendon which winds round the pterygoid hamulus, passes through the origin of the buccinator, and flattens out to form the palatine aponeurosis. Aponeurosis is attached to:
a. Posterior border of hard palate
b. lnferior surface of palate behind the palatine crest
Nerve Supply - Mandibular Nerve
Action
a. Tightens the soft palate, chiefly the anterior part
b. Opens the auditory tube to equalize air pressure between the middle ear and the nasopharynx
Levator Veli Palatini Muscle
This is a cylindrical muscle that lies deep to the tensor veli palatini
Origin
a. lnferior aspect of auditory tube
b. Adjoining part of inferior surface of petrous temporal bone
Insertion
Muscle enters the pharynx by passing over the upper concave margin of the superior constrictor, runs downwards and medially and spreads out in the soft palate.
lt is inserted into the upper surface of the palatine aponeurosis
Nerve Supply - Cranial part of accessory nerve through vagus nerve by forming pharyngeal plexus
Action
a. Elevates soft palate and closes the pharyngeal isthmus
b. Opens the auditory tube, like the tensor veli palatini
Musculus uvulae
This is a longitudinal strip placed on each side of the median plane, within
the palatine aponeurosis
Origin
a. Posterior nasal spine
b. Palatine aponeurosis
Insertion - Mucous membrane of uvula
Nerve Supply - Cranial part of accessory nerve through vagus nerve by forming pharyngeal plexus
Action - Pulls up the uvula
Palatoglossus
Origin
Oral surface of palatine aponeurosis
Insertion
Descends in the palatoglossal arch, to the side of the tongue at the junction of its oral and pharyngeal parts
Nerve Supply - Cranial part of accessory nerve through vagus nerve by forming pharyngeal plexus
Action
Pulls up the root of the tongue, approximates the palatoglossal arches, and thus closes the oropharyngeal isthmus
Palatopharyngeus
It consists of two fasciculi that are separated by the levator veli palatini
Origin
a. Anterior fasciculus from posterior border of hard palate b. Posterior fasciculus; from the palatine aponeurosis Insertion
Descends in the palatopharyngeal arch and spreads out to form the greater part of longitudinal muscle coat of pharynx.
lt is inserted into:
a. Posterior border of the lamina of the thyroid cartilage
b. Wall of the pharynx and its median raphe
Nerve Supply - Cranial part of accessory nerve through vagus nerve by forming pharyngeal plexus
Action
Pulls up the wall of the pharynx and shortens it during swallowing
• Passavant’s Ridge
Some of the upper fibres of the palatopharyrgeus Pass circularly deep to the mucous membrane of the
pharynx, and form a sphincter internal to the superior constrictor.
These fibres constitute Passavant's muscle which on contraction raises a ridge called the Passavant's ridge on the posterior wall of the nasopharynx.
When the soft palate is elevated it comes in contact with this ridge, the two together closing the pharyngeal isthmus between the nasopharynx and the oropharynx
Movements and Functions of the Soft Palate
The palate controls two gates, upper air way or the pharyngeal isthmus and the upper food way or oropharyngeal isthmus. The upper air way crosses the upper food way.
The soft palate can completely close them, or can regulate their size according to requirements.
Through these movements, the soft palate plays an important role in chewing, swallowing, speech, coughing, sneezing, etc.
A few specific roles are given below.
1. It isolates the mouth from the oropharynx during chewing, so that breathing is unaffected.
2. It separates the oropharynx from the nasopharynx by locking Passavant's ridge during the second stage of swallowing, so that food does not enter the nose.
3. By varying the degree of closure of the pharyngeal isthmus, the quality of voice can be modified and various consonants are correctly pronounced.
4. During sneezing, the blast of air is appropriately divided and directed through the nasal and oral
cavities without damaging the narrow nose.
Similarly during coughing, it directs air and sputum into the mouth and not into the nose
Blood Supply
Arteries
1. Greater palatine branch of maxillary artery
2 Ascending palatine branch of facial artery.
3 Palatine branch of ascending pharyngeal artery
Veins
They pass to the pterygoid and tonsillar plexuses of veins.
Lymphatic Drainage
Drain into the upper deep cervical and retropharyngeal lymph nodes.
DEVELOPMENT OF PALATE
The premaxilla or primitive palate carrying upper four incisor teeth is formed by the fusion of medial nasal folds, which are folds of frontonasal process.
The rest of the palate is formed by the shelf-like palatine processes of maxilla and horizontal plates of palatine bone. Most of the palate gets ossified to form
The unossified posterior part of fused palatal processes forms the soft palate.
STRUCTURE
Soft palate comprises epithelium, connective tissue and muscles.
Epithelium is from the ectoderm of maxillary process.
The muscles are derived from 1st, 4th and 6th branchial arches and accordingly are innervated by mandibular and vagoaccessory complex
Cleft palate is a congenital defect caused by nonfusion of the right and left palatal processes.
It may be of different degrees.
In the least severe type, the defect is confined to the soft palate.
In the most severe cases, the cleft in the palate is continuous with harelip.
Paralysis of the soft palate in lesions of the vagus nerve produces:
a. Nasal regurgitation of liquids
b. Nasal twang in voice
c. Flattening of the palatal arch
d. Deviation of uvula to normal side
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