Tongue

Lore & Background

The human tongue is divided into an anterior oral part and a posterior pharyngeal part by the terminal sulcus, a V-shaped groove. The anterior part makes up roughly two-thirds of the tongue's length, while the posterior part constitutes about one-third. The left and right sides are separated by the lingual septum, visible as the median sulcus on the surface. The tongue is a muscular hydrostat, richly supplied with nerves and blood vessels, and kept moist by saliva. The tongue's eight muscles are classified as intrinsic or extrinsic. The four intrinsic muscles alter the shape of the tongue and are not attached to bone; they include the superior longitudinal, inferior longitudinal, vertical, and transverse muscles. The four extrinsic muscles change the position of the tongue and are anchored to bone: genioglossus, hyoglossus, styloglossus, and palatoglossus. The genioglossus is known as the tongue's 'safety muscle' as it is the only muscle that propels the tongue forward. The word 'tongue' derives from Old English tunge, from Proto-Germanic *tungōn, with cognates in many Germanic languages. The ue ending appeared in the fourteenth century as an attempt to show 'proper pronunciation' but is 'neither etymological nor phonetic.'

Reader's Guide

The tongue is a critical organ in human physiology and communication. As a muscular hydrostat, it manipulates food for chewing and swallowing, houses taste buds in lingual papillae, and enables speech. Its structure includes a division into anterior and posterior parts, each with different embryological origins and nerve supplies: the anterior two-thirds receive taste via the chorda tympani branch of the facial nerve, while the posterior part is supplied by the glossopharyngeal nerve. The tongue's blood supply comes primarily from the lingual artery, a branch of the external carotid artery. The tongue's role extends beyond digestion and taste; it is essential for speech in humans and vocalization in other animals. Its intrinsic and extrinsic muscles allow precise movements for articulation, swallowing, and cleaning the teeth. The tongue's resting posture also influences mouth and face development. The distinction between the tip and blade of the tongue is important in phonetics, where apical and laminal sounds are differentiated. The tongue's etymology reflects its long history in Germanic languages, with spelling variations persisting into the sixteenth century.

Did You Know?

• The tongue is a muscular hydrostat that forms part of the floor of the oral cavity.
• The average length of the human tongue from the oropharynx to the tip is 10 cm.
• The genioglossus muscle is known as the tongue's 'safety muscle' because it is the only muscle that propels the tongue forward.
• The word 'tongue' derives from Old English tunge, from Proto-Germanic *tungōn.