The Anatomy of Tongue

TONGUE

The tongue, together with its associated muscles, forms the floor of the oral cavity. It is and accessory structure of the digestive system composed of skeletal muscle covered with mucous membrane. The tongue is divided into symmetrical lateral halves by a median septum that extends throughout its entire length and is attached inferiorly to the hyoid bone. Each half of the tongue consists of an identical complement of extrinsic and intrinsic muscles.

The extrinsic muscles of the tongue originate outside the tongue and insert into it. They include the hyoglossus, genioglossus, and styloglossus. The extrinsic muscles move the tongue from side to side and in and out. These movements maneuver food for chewing, shape the food into a rounded mass, and force the food to the back of the mouth for swallowing. They also form the floor of the mouth and hold the tongue in position. The intrinsicmuscles originate and insert within the tongue and alter the shape and size of the tongue for speech and swallowing. The intrinsic muscles include the longitudinalis superior, longitudinalis inferior, transverses linguae, and verticalis linguae. The lingual frenulum, a fold of mucous membrane In the midline of the undersurface of the tongue, aids in limiting the movement of the tongue posteriorly.

The upper surface and sides of the tongue are covered with papillae, projections of the lamina propria covered with epithelium. Filiform papillae are conical projections distributed in parallel rows over the anterior two-thirds of the tongue. They are whitish and contain no taste bud. Fungiform papillae are mushroomlike elevations distributed among the filiform papillae and are more numerous near the tip of the tongue. They appear as red dots on the surface of the tingue, and most of them contain taste buds. Circumvallate papillae, 10 to 12 in number, are arranged in the form of an inverted V on the posterior surface of the tongue, and all of them contain taste buds.