Palate
PALATE
- Palate is the roof of mouth that seperates oral cavity from nasal cavity.
- It has 2 parts:
- HARD PALATE( Bony)
- SOFT PALATE( Muscular)
DEVELOPMENT:
- Initially, during the 6th week of intrauterine development, there is a common oro-nasal cavity bounded anteriorly by the primary palate and occupied mainly by the developing tongue
- Formation of the palate involves the fusion of two processes: Right and left maxillary processes and the Medial nasal process
- Median nasal process: Grows downward and forward to form the nasal septum
- Primary Palate(medial part) :Develops first and is a floor to the nasal pits.
- Formed by the merging of the two median nasal processes
- Small part lying anterior to the incisive fossa, of the adult hard palate
3. Lateral palatine process:
- Develop from the maxillary processes laterally & grow to midline.
- In the beginning, the lateral palatine processes project inferomedially on each side of the tongue
- As a result of the enlargement of the mandible and a change in the degree of flexion of the fetus head, the tongue moves inferiorly.
- When the tongue is removed from the path of the growing lateral palatine processes, the processes are straightened to a horizontal position.
- Then lateral palatine processes grows medially at the midline and fuse with each other and with the posterior part of the primary palate and nasal septum to give rise to the hard and soft palate
- Secondary Palate: Between the 7th and 8th weeks of development
- Primary and secondary palates are divided by Incisive foramen
ANATOMY
HARD PALATE:
- Separates the oral cavity from the nasal cavities.
- It consists of a bony plate covered above and below by mucosa:
- Above, it is covered by respiratory mucosa and forms the floor of the nasal cavities (superior surface)
- Below , it is covered by a tightly bound layer of oral mucosa and forms much of the roof of the oral cavity (inferior surface)
- The posterior margins gives attachment to soft palate.
- The anterolateral margins are continuous with alveolar arches and gums.
SOFT PALATE:
- Movable muscular fold suspended from posterior border of hard palate
- Separates nasopharynx from oropharynx (Traffic controller)
- 2 surfaces: Covered on its upper and lower surfaces by mucous membrane
- Composed of:Muscle fibers, An aponeurosis, Lymphoid tissue, Glands, Blood vessels & Nerves
Passavant’s Ridge:
- Upper fibers of palatopharyngeus pass deep to the mucous membrane of the pharynx and form a sphincter internal to the sup. Constrictor.
- These fibers constitute passavant’s muscle which on contraction raises passavant’s ridge on posterior wall of nasopharynx.
- When soft palate is elevated it comes in contact with the ridge and close the pharyngeal isthmus between nasopharynx and oropharynx.
MUSCLES OF PALATE
| MUSCLES | ORIGIN | INSERTION | ACTION |
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Tensor veli palatine |
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(a) Posterior border of hard palate (b)Inf surface of palate behind palatine crest |
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| Levator veli palatini |
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| Musculus uvulae |
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| Palatopharyngeus |
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| Palatoglossus |
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NERVE SUPPLY & BLOOD SUPPLY:
HARD PALATE:
- Greater palatine & nasopalatine branches of pterygopalatine ganglion suspended by the maxillary nerve.
- ARTERIES- Greater palatine branch of maxillary artery.
- VEINS- Drains into pterygoid plexus of veins.
SOFT PALATE:
Sensory Nerve Supply:
- General Sensory: Mostly by the maxillary nerve through its branches:
- Middle lesser palatine nerve
- Posterior lesser palatine nerve
- Special Sensory: For taste sensations: lesser palatine nerves, greater petrosal nerve geniculate ganglion of facial nerve nucleus of solitary tract.
- Secretomotor:Lesser palatine nerves Derived from sup. salivatory nucleus travel through greater petrosal nerves.
Motor Nerve Supply:
- All the muscles, except tensor veli palatini, are supplied by:Pharyngeal plexus(derived from cranial part of accessory nerve through vagus)
- Tensor veli palatini supplied by the:Nerve to medial pterygoid(V3)
Arteries
- Greater palatine branch of the maxillary artery
- Ascending palatine branch of the facial artery
- Palatine branch of Ascending pharyngeal, branch of the external carotid artery
Veins-
- Pterygoid and tonsillar plexus of veins
Exam Question
- Cranial part of accessory nerve supplies all palatal muscles, except tensor veli palatini
- The sensory supply of the palate is through Glossopharyngeal, maxillary nerve, facial nerve
- Pharyngeal plexus supply muscles of soft palate
- Tensor veli palatini is supplied by mandibular nerve
- Middle and posterior lesser palatine nerves supply soft palate and tonsil
- Pharyngeal plexus supply all muscles of soft palate except Tensor veli palatine
- Primary and secondary palates are divided by Incisive foramen
- Sensory fibres from the taste buds in the hard and soft palate travel along Facial nerve
- Tensor veli palatine, Levator veli palatini helps to open Eustachian tube while sneezing
- Palatoglossus is derived from the 6th arch
- Passavant ridge is formed by Superior constrictor and palatopharyngeus
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Don’t Forget to Solve all the previous Year Question asked on Palate