Uvula

The uvula is a small, conical, fleshy projection that hangs from the posterior free margin of the soft palate at the midline. It is composed of muscle, connective tissue, and mucosa and plays an important role in speech, swallowing, and closure of the nasopharynx. Although small, it contributes significantly to the coordinated movement of the soft palate.

Structure

• Shape: Conical and elongated, tapering distally
• Location: Midline posterior edge of the soft palate, above the oropharynx
• Composition: Core of musculus uvulae, covered with mucous membrane and containing minor mucous glands

Muscle – Musculus Uvulae

The musculus uvulae is a paired muscle located within the uvula. Its primary functions include retraction and elevation of the uvula during swallowing and phonation.

• Origin: Posterior nasal spine and palatine aponeurosis
• Insertion: Mucosa of the uvula
• Action: Shortens and elevates the uvula; contributes to the sealing of the nasopharynx during swallowing
• Innervation: Pharyngeal plexus via the vagus nerve (cranial nerve X)

Functions

• Swallowing: Elevates with the soft palate to help close off the nasopharynx and prevent food or liquid from entering the nasal cavity
• Speech: Aids in articulation by helping direct airflow during certain phonemes, particularly in some languages
• Gag reflex: Stimulation of the uvula contributes to triggering the pharyngeal reflex, providing a protective mechanism against choking
• Lubrication: Contains mucous glands that help moisten the oropharynx and facilitate swallowing

Blood Supply

• Arterial supply: Primarily from the lesser palatine artery (branch of the descending palatine artery from the maxillary artery)
• Venous drainage: Drains into the pterygoid venous plexus and surrounding pharyngeal veins

Nerve Supply

• Motor innervation: Via the pharyngeal plexus, primarily through the vagus nerve (CN X)
• Sensory innervation: Lesser palatine nerve, a branch of the maxillary nerve (CN V2)

Relations

• Superiorly: Attached to the posterior margin of the soft palate
• Inferiorly: Suspended above the oropharyngeal isthmus
• Laterally: Flanked by the palatoglossal and palatopharyngeal arches

Clinical Significance

• Uvula deviation: A sign of vagus nerve (CN X) palsy; the uvula deviates away from the side of the lesion due to unopposed musculus uvulae on the intact side
• Bifid uvula: A congenital anomaly where the uvula is split or forked; may be associated with submucous cleft palate
• Uvulitis: Inflammation of the uvula, often due to infection, trauma, or allergic reaction; presents with swelling, pain, and dysphagia
• Snoring and sleep apnea: An elongated uvula may contribute to upper airway obstruction; uvulopalatopharyngoplasty (UPPP) is a surgical procedure to address this
• Gag reflex testing: Stroking the uvula or posterior pharynx helps assess cranial nerves IX (glossopharyngeal) and X (vagus)

Imaging

• Endoscopy: Direct visualization during oral or nasal endoscopy helps assess uvular size, mobility, and symmetry
• MRI/CT: Rarely needed for isolated uvular assessment but may be used in evaluating oropharyngeal masses or congenital anomalies

Development

The uvula forms during the development of the secondary palate. It originates from the posterior extension of the palatine shelves. Incomplete fusion during embryogenesis can result in anomalies such as a bifid uvula or submucosal cleft palate.