Anatomy & Histology · single question
Which muscle displaces a mandibular denture when the tongue is protruded?
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Correct answer: A. Genioglossus
Genioglossus (A) is the main tongue protrusion muscle and displaces the mandibular denture anteriorly/superiorly when the tongue protrudes. The genioglossus originates from the superior mental spine (genial tubercle) on the inner surface of the mandibular symphysis and fans out to insert into the tongue. When it contracts for protrusion, it pushes against the lingual flange of the lower denture.
• Denture borders must accommodate muscle attachments: the lingual flange must be shaped to allow genioglossus action without displacing the denture.
• Other muscles affecting denture stability: Buccinator (lateral displacement), Mentalis (anterior displacement of lower denture), Orbicularis oris (anterior border of upper denture).
• Masseter is a masticatory muscle — attaches to ramus, not directly involved in denture displacement.
• Denture borders must accommodate muscle attachments: the lingual flange must be shaped to allow genioglossus action without displacing the denture.
• Other muscles affecting denture stability: Buccinator (lateral displacement), Mentalis (anterior displacement of lower denture), Orbicularis oris (anterior border of upper denture).
• Masseter is a masticatory muscle — attaches to ramus, not directly involved in denture displacement.
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