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M01.02.050 Palate
The palate, commonly referred to as the “roof of the mouth,” separates the nasal cavity from the oral cavity. It is divided into two distinct parts:
- Hard Palate: Composed of bone and immobile.
- Soft Palate: Composed of muscle fibers covered by a mucous membrane and can elevate to close the pharyngeal isthmus during swallowing, preventing food from entering the nasopharynx.
This guide will provide an overview of the palate’s structure, function, neurovascular supply, and associated clinical relevance.
Structure of the Palate
The palate is positioned between the nasal cavity (superior) and oral cavity (inferior), forming:
- Roof of the mouth
- Floor of the nasal cavity
Mucosal Linings
- Superior aspect (nasal cavity): Covered by respiratory epithelium.
- Inferior aspect (oral cavity): Lined by oral mucosa, containing secretory salivary glands.
Hard Palate
Composition
The hard palate forms the anterior portion and consists of:
- Palatine processes of the maxilla.
- Horizontal plates of the palatine bones.
Foramina and Canals
| Foramen/Canal | Location | Structures Transmitted |
|---|---|---|
| Incisive canal | Anterior midline | Nasopalatine nerve, descending palatine artery |
| Greater palatine foramen | Medial to the third molar tooth | Greater palatine nerve and vessels |
| Lesser palatine foramina | Pyramidal process of palatine bone | Lesser palatine nerve |
Soft Palate
Composition
The soft palate is the posterior mobile part of the palate, continuous with the hard palate and the palatine aponeurosis.
Key Features
- Posterior Border: Free, with a central structure called the uvula.
- Roof of Fauces: Connects oral cavity and pharynx.
- Arches:
- Palatoglossal arch (anteriorly)
- Palatopharyngeal arch (posteriorly)
- Palatine Tonsils: Situated in the tonsillar fossae between the arches.
Muscles of the Soft Palate
| Muscle | Attachments | Function | Innervation |
|---|---|---|---|
| Tensor veli palatini | Medial pterygoid plate → Palatine aponeurosis | Tenses the soft palate | Medial pterygoid nerve (CN V3) |
| Levator veli palatini | Petrous temporal bone → Palatine aponeurosis | Elevates the soft palate | Pharyngeal branch of vagus (CN X) |
| Palatoglossus | Palatine aponeurosis → Side of tongue | Pulls palate toward the tongue | Pharyngeal branch of vagus (CN X) |
| Palatopharyngeus | Palatine aponeurosis → Thyroid cartilage | Tenses soft palate, aids swallowing | Pharyngeal branch of vagus (CN X) |
| Musculus uvulae | Posterior nasal spine → Uvula mucosa | Shortens the uvula | Pharyngeal branch of vagus (CN X) |
Neurovascular Supply
Arterial Supply
- Primary: Greater palatine arteries (from the greater palatine foramen).
- Collateral: Anastomosis of the lesser palatine artery with ascending palatine artery.
Venous Drainage
- Drains into the pterygoid venous plexus.
Innervation
| Nerve | Region Innervated |
|---|---|
| Greater palatine nerve | Most glandular structures of the hard palate |
| Lesser palatine nerve | Soft palate |
| Nasopalatine nerve | Mucosa of the anterior hard palate |
Clinical Relevance: Cleft Lip and Palate
Definition
A cleft is a gap or split in the lip or palate caused by developmental defects.
Types
| Condition | Cause |
|---|---|
| Cleft Lip | Failure of medial nasal and maxillary prominences to fuse |
| Cleft Palate | Failure of palatal shelves to fuse |
Prevalence and Implications
- Occurs in ~1/1000 births; higher rates (~1/250) in Native Americans.
- Complications:
- Difficulty feeding (potentially life-threatening in infants).
- Speech impediments.
- Recurrent ear infections.
Key Points to Remember
- The hard palate provides structural separation and support, while the soft palate aids swallowing by closing the nasopharynx.
- Tensor veli palatini is the only soft palate muscle not innervated by the vagus nerve.
- Cleft lip/palate requires early intervention to mitigate feeding and speech challenges.
References
- TeachMeSeries Ltd (2024). Anatomy of the Palate.