PART 12 — TONGUE

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Study use: Rapid revision of tongue embryology, sensory and motor innervation, papillae, common tongue lesions, nutritional and systemic clues, congenital disorders, and oral-tongue carcinoma. Management is intentionally concise and should be interpreted with age, immune status, airway risk, pathology, disease extent, and functional impairment.

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Priority Guide: 🔴 Core / Must Know | 🟠 Important | 🟡 Additional

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🎯 High-Yield Overview

• Anterior ⅔: general sensation → lingual nerve (V3); taste → chorda tympani (VII).
• Posterior ⅓: general sensation + taste → glossopharyngeal nerve (IX); extreme posterior/epiglottic region → X.
• Tongue motor → CN XII except palatoglossus → CN X.
• Genioglossus protrudes the tongue and is the classic “safety muscle”; LMN XII palsy makes the tongue deviate toward the weak side with atrophy/fasciculations.
• Filiform papillae have no taste buds; circumvallate papillae lie anterior to the sulcus terminalis but taste is carried mainly by IX.
• Map-like migrating red patches → geographic tongue; dark elongated filiform papillae → black hairy tongue.
• Smooth beefy-red tongue suggests nutritional atrophic glossitis; magenta tongue + angular cheilitis → riboflavin deficiency.
• Macroglossia + nephrotic proteinuria/restrictive cardiomyopathy → strongly consider AL amyloidosis.
• Midline base-of-tongue thyroid tissue → lingual thyroid; confirm whether normally located thyroid tissue exists before destructive treatment.
• Persistent indurated/nonhealing lateral-tongue lesion → urgently exclude squamous-cell carcinoma.

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RED FLAGS: Acute tongue swelling with stridor, drooling, inability to handle secretions, or respiratory distress is an airway emergency. A persistent unexplained tongue ulcer/mass, induration, reduced tongue mobility, cervical node, or unexplained weight loss requires malignancy assessment.

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1. EMBRYOLOGY, LANDMARKS, INNERVATION & PAPILLAE

2. BENIGN & INFECTIOUS SURFACE LESIONS

3. ATROPHIC GLOSSITIS, NUTRITIONAL CLUES & STRAWBERRY TONGUE

4. MACROGLOSSIA & SYSTEMIC TONGUE SIGNS

5. ANKYLOGLOSSIA & LINGUAL THYROID