SN5
SHORT NOTE
5M
★ High-yield
Describe the tongue with its papillae, muscles and nerve supply. Add a note on hypoglossal nerve palsy.
General Features
The tongue is a muscular organ concerned with taste, mastication, deglutition, speech and cleaning the teeth.
- Divided by the V-shaped sulcus terminalis into an anterior two-thirds (oral) and a posterior one-third (pharyngeal)
- The foramen caecum at the apex of the sulcus marks the origin of the thyroglossal duct
Papillae
| Papilla | Position | Taste buds |
|---|---|---|
| Filiform | Most numerous, over the anterior two-thirds | None — the only papilla without them |
| Fungiform | Tip and margins | Present |
| Vallate (circumvallate) | 8–12 in a V just in front of the sulcus terminalis | Numerous |
| Foliate | Sides, posteriorly | Present, rudimentary in man |
Muscles
| Type | Muscles | Action |
|---|---|---|
| Intrinsic | Superior and inferior longitudinal, transverse, vertical | Alter the shape of the tongue |
| Extrinsic — genioglossus | From the genial tubercle | Protrudes the tongue; the "safety muscle" of the tongue |
| Hyoglossus | From the hyoid | Depresses |
| Styloglossus | From the styloid process | Retracts and elevates |
| Palatoglossus | From the palatine aponeurosis | Elevates the root; the only one supplied by the vagus (pharyngeal plexus), not the hypoglossal |
Nerve Supply — the Key Table
| Region | General sensation | Taste | Motor |
|---|---|---|---|
| Anterior two-thirds | Lingual nerve (V3) | Chorda tympani (VII) | Hypoglossal (XII) — all muscles except palatoglossus |
| Posterior one-third | Glossopharyngeal (IX) | Glossopharyngeal (IX) | Hypoglossal |
| Vallate papillae | Glossopharyngeal — though anatomically in front of the sulcus | Glossopharyngeal | — |
| Posterior-most part (near the epiglottis) | Internal laryngeal (X) | Internal laryngeal (X) | — |
Applied Aspects
- Hypoglossal nerve palsy — on protrusion the tongue deviates toward the paralysed side, because the normal genioglossus pushes it across. There is wasting and fasciculation on that side in a lower motor neurone lesion
- Genioglossus is the safety muscle — bilateral paralysis, or loss of tone under anaesthesia, allows the tongue to fall back and obstruct the airway; hence the jaw thrust and the oropharyngeal airway
- Lymphatic drainage governs cancer surgery — the tip drains to the submental nodes bilaterally, the sides to the submandibular, and the posterior third to the deep cervical nodes bilaterally. Midline lesions therefore need bilateral neck dissection
- Carcinoma of the tongue is common in India from tobacco chewing; the lateral border is the usual site, and it presents as a painless ulcer with rolled edges
- Ankyloglossia (tongue tie) — a short frenulum restricting protrusion, interfering with feeding and speech
All questions in Head & Neck
- Q1Describe the triangles of the neck with their boundaries and contents. Add a note on the posterior triangle and its applied anatomy. ★
- Q2Describe the thyroid gland under relations, blood supply and nerve relations. Add a note on the applied anatomy of thyroidectomy. ★
- Q3Describe the parotid gland under bed, structures within it, duct and nerve supply. Add a note on its applied anatomy. ★
- Q4Describe the larynx under cartilages, cavity, muscles and nerve supply. Add a note on vocal cord palsy. ★
- Q5Describe the cavernous sinus with its contents and connections. Add a note on cavernous sinus thrombosis and the dangerous area of the face. ★
- SN1Describe the course and branches of the facial nerve. Differentiate upper from lower motor neurone facial palsy. ★
- SN2Describe the temporomandibular joint with its movements. Add a note on its dislocation. ★
- SN3Describe the submandibular gland with its relations, duct and nerve supply. ★
- SN4Describe the layers of the deep cervical fascia and the fascial spaces of the neck. ★
- SN5Describe the tongue with its papillae, muscles and nerve supply. Add a note on hypoglossal nerve palsy. ★
- SN6Describe the layers of the scalp with their clinical importance. ★
- SN7Describe the trigeminal nerve with its divisions and distribution. Add a note on the associated parasympathetic ganglia.