The palatine tonsil sits in a fossa between two mucosal folds. Which muscle forms the ANTERIOR pillar, lying in front of the tonsil?

Correct answer: C. Palatoglossus

• A. PALATOPHARYNGEUS forms the POSTERIOR pillar (palatopharyngeal arch), behind the tonsil. The tonsil sits in the triangular fossa between the two arches, so this is the mirror-image answer.
• B. STYLOGLOSSUS runs from the styloid process to the tongue and lies lateral to the tonsillar bed, outside the pharyngeal wall. It retracts and elevates the tongue and is not one of the two visible arches.
• C. CORRECT. The PALATOGLOSSUS muscle raises the anterior tonsillar pillar (the palatoglossal arch), which lies immediately ANTERIOR to the palatine tonsil. It runs from the palatine aponeurosis down to the side of the tongue, and its action is to elevate the posterior tongue and narrow the oropharyngeal isthmus during swallowing. Uniquely among tongue muscles, it is supplied by the PHARYNGEAL PLEXUS (CN X) rather than the hypoglossal nerve.
• D. The SUPERIOR PHARYNGEAL CONSTRICTOR lies DEEP (lateral) to the tonsil, forming the floor of the tonsillar bed — not a pillar. It separates the tonsil from the styloglossus and the glossopharyngeal nerve beyond.

Note: Clinically important because the GLOSSOPHARYNGEAL NERVE (CN IX) runs just deep to the inferior pole of the tonsil — this is why tonsillectomy can injure CN IX and cause loss of taste on the posterior third of the tongue, and why referred otalgia is common after tonsillar disease.