The palatoglossus forms the palatoglossal arch (anterior pillar of the fauces) and is the only tongue muscle supplied by the vagus nerve via the pharyngeal plexus rather than the hypoglossal nerve. It closes the oropharyngeal isthmus during chewing to keep food in the oral cavity, and its failure in vagal palsy explains the dysphagia associated with unilateral vagal lesions at the level of the pharyngeal plexus.
| Origin | Palatine aponeurosis of the soft palate |
|---|---|
| Insertion | Side of the tongue blending with the transverse tongue fibres |
| Nerve Supply | Pharyngeal plexus via the vagus nerve (CN X) — the only tongue muscle NOT supplied by CN XII |
| Blood Supply | Ascending palatine artery |
| Actions | Elevates the posterior tongue; Depresses and narrows the soft palate; Closes the oropharyngeal isthmus (palatoglossal arch) to separate the oral cavity from the oropharynx during chewing |
|---|
By simultaneously elevating the back of the tongue and lowering the soft palate it seals the oral cavity from the oropharynx during the oral phase of chewing, preventing premature spillage of the food bolus into the pharynx before the swallowing reflex is initiated.
The palatoglossal arch is the landmark for tonsillectomy — the anterior pillar incision in tonsillectomy begins at this arch. Vagal nerve palsy produces loss of palatoglossus function contributing to the nasal regurgitation, reduced gag reflex, and swallowing difficulty of unilateral pharyngeal palsy.
Not directly palpable but visible on oral examination as the fold of mucosa connecting the soft palate to the base of the tongue bilaterally.
Post-tonsillectomy scarring of the palatoglossus producing velopharyngeal dysfunction or restricted mouth opening from anterior pillar contracture.
