Soft Palate

The soft palate is a mobile, muscular extension of the hard palate located at the posterior portion of the roof of the mouth. It plays a key role in separating the nasopharynx from the oropharynx during swallowing and speech. Unlike the bony hard palate, the soft palate is composed of muscles, mucosa, and connective tissue, allowing it to elevate, depress, and move laterally as needed for functional tasks.

Structure

The soft palate is a flexible, fibromuscular structure suspended from the posterior edge of the hard palate. It ends in a conical projection called the uvula.

• Anterior attachment: To the posterior margin of the hard palate
• Posterior free margin: Contains the uvula and extends between the oropharynx and nasopharynx
• Laterally: Merges with the pharyngeal wall to form the palatoglossal and palatopharyngeal arches

Muscles of the Soft Palate

There are five paired muscles that contribute to the structure and function of the soft palate:

• Tensor veli palatini: Tenses the soft palate and opens the pharyngotympanic tube during swallowing
• Levator veli palatini: Elevates the soft palate to close off the nasopharynx during swallowing
• Palatoglossus: Draws the soft palate down and the tongue up; forms the palatoglossal arch
• Palatopharyngeus: Tenses the soft palate and pulls the pharyngeal walls upward; forms the palatopharyngeal arch
• Musculus uvulae: Elevates and retracts the uvula, helping to close the nasopharynx

Blood Supply

• Greater and lesser palatine arteries: Branches of the descending palatine artery (from the maxillary artery)
• Ascending palatine artery: Branch of the facial artery
• Ascending pharyngeal artery: Branch of the external carotid artery

Venous drainage is via the pterygoid venous plexus and facial veins.

Nerve Supply

• Motor innervation: All muscles of the soft palate except tensor veli palatini are supplied by the pharyngeal plexus (via the vagus nerve, CN X); tensor veli palatini is innervated by the mandibular nerve (V3)
• Sensory innervation: Supplied mainly by the lesser palatine nerve (branch of CN V2)

Mucosal Covering

The soft palate is covered by non-keratinized stratified squamous epithelium on the oral surface and pseudostratified columnar epithelium with cilia on the nasal surface. Numerous mucous glands are present, especially near the uvula and posterior region.

Functions

• Swallowing: Elevates to close off the nasopharynx and prevent food or liquid from entering the nasal cavity
• Speech: Modifies resonance and articulation by directing airflow through the mouth or nose
• Breathing coordination: Adjusts positioning during nasal or oral breathing

Related Structures

• Uvula: Conical projection at the posterior midline of the soft palate; involved in gag reflex and nasopharyngeal closure
• Palatoglossal arch: Fold of mucosa overlying the palatoglossus muscle; forms the anterior tonsillar pillar
• Palatopharyngeal arch: Fold of mucosa over the palatopharyngeus muscle; forms the posterior tonsillar pillar
• Tonsillar fossa: Space between the arches that houses the palatine tonsils

Development

The soft palate develops from the posterior portion of the lateral palatine processes during embryogenesis. Unlike the hard palate, it does not ossify. Failure of the soft palate to properly fuse in the midline results in cleft soft palate, often associated with speech and feeding difficulties.

Clinical Significance

• Cleft soft palate: Congenital defect that may occur alone or with cleft hard palate; often requires surgical correction
• Velopharyngeal insufficiency: Failure of the soft palate to seal off the nasopharynx during speech; leads to hypernasal voice
• Uvula deviation: In lesions of the vagus nerve (CN X), the uvula deviates away from the affected side
• Sleep apnea: A long or floppy soft palate may obstruct the airway during sleep; treated with surgery or CPAP
• Palatal myoclonus: Involuntary rhythmic contractions of the palatal muscles; may be idiopathic or related to brainstem lesions

Imaging

• MRI: Useful for evaluating soft tissue masses, palatal muscle function, or congenital anomalies
• CT scan: Helps assess structural deformities and plan surgical repair of cleft palate
• Nasendoscopy: Endoscopic assessment of soft palate movement during speech and swallowing