Surgical Anatomy of the Tongue

Introduction

The tongue is a mass of striated muscles covered with mucous membrane. It is a mobile muscular organ that can assume various shapes and positions. It is partly located in the oral cavity and partly in the pharynx.

Functions of the Tongue

Forming words during speech
Squeezing food into the pharynx during swallowing
Mastication
Taste perception
Deglutition
Articulation and oral cleansing

Parts and Surfaces of the Tongue

Root: Posterior one-third (pharyngeal portion)
Body: Anterior two-thirds
Apex: Pointed anterior part
Dorsum
Ventral surface

The terminal sulcus (a V-shaped groove) divides the dorsum into anterior and posterior parts.

Surface Characteristics

The anterior dorsum has a thin mucous membrane and is rough due to various papillae:

Vallate: Just anterior to the terminal sulcus
Foliate: Poorly developed in humans
Filiform: Most common
Fungiform: Found at the apex and sides

Taste receptors are located in vallate, foliate, and fungiform papillae. Additional taste buds are found on the soft palate, posterior oropharynx wall, and epiglottis.

The posterior tongue lacks papillae but contains lingual tonsils—nodules of lymphatic tissue giving it a cobblestone appearance.

Inferior Surface

This surface has a thin, transparent mucous membrane with visible veins. Structures include the lingual frenulum, deep lingual vein, and sublingual caruncle (openings of Wharton's ducts).

Muscles of the Tongue

Intrinsic muscles: (4 on each side) alter the shape of the tongue. All are supplied by CN XII.

Extrinsic muscles: (4 on each side) alter tongue position. All are supplied by CN XII, except palatoglossus.

Extrinsic Muscles

Muscle	Origin	Insertion
Genioglossus	Superior part of mental spine of mandible	Dorsum of tongue, body of hyoid
Hyoglossus	Body and greater horn of hyoid	Lateral and ventral tongue
Styloglossus	Styloid process and stylohyoid ligament	Side of tongue
Palatoglossus	Palatine aponeurosis of soft palate	Side of tongue

Intrinsic Muscles

Muscle	Origin	Insertion
Superior Longitudinal	Submucous fibrous layer, median fibrous septum	Margins of tongue, mucous membrane
Inferior Longitudinal	Root of tongue	Apex of tongue
Transverse	Median septum	Fibrous tissue at margin of tongue
Vertical	Superior surface of tongue borders	Inferior surface of tongue borders

Innervation

Motor: All muscles by CN XII except palatoglossus (via cranial root of CN XI through CN X)
Touch & Temperature: Anterior two-thirds by lingual nerve; posterior third by glossopharyngeal nerve
Taste: Chorda tympani (CN VII) for anterior two-thirds; Internal laryngeal nerve (CN X) for epiglottic area

Taste Zones

Sweet: Apex (tip)
Salty: Lateral margins
Sour & Bitter: Posterior part

Vasculature

Arteries

Supplied by the lingual artery (dorsal, deep, and sublingual branches). The dorsal arteries communicate near the apex; the fibrous septum prevents communication of other branches.

Veins

Dorsal lingual veins
Deep lingual veins (join sublingual veins)

Drain into the internal jugular vein.

Lymphatic Drainage

Posterior third → Superior deep cervical nodes
Medial anterior two-thirds → Inferior deep cervical nodes
Lateral anterior two-thirds → Submandibular nodes
Apex → Submental nodes

Clinical Considerations

Highly vascular → Useful for oral reconstruction (tongue flaps)
Rarely affected in cancrum oris
Severed anterior attachment in mandibular fractures may cause airway obstruction

Common Tongue Conditions

Ankyloglossia (tongue tie)
Candidiasis and geographic tongue
Tongue carcinomas
Lymphangioma, hemangioma

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