The tongue is the large bundle of skeletal muscles on the floor of the mouth that manipulates food for chewing and swallowing (deglutition). It is the primary organ of taste. Much of the upper surface of the tongue is covered in papillae and taste buds. The tongue, with its wide variety of possible movements, assists in forming the sounds of speech. It is sensitive and kept moist by saliva, and is richly supplied with nerves and blood vessels to help it move.

Structure

The penisdorsum (upper surface) of the tongue can be divided into two parts:

• an oral part (anterior two-thirds of the tongue) that lies mostly in the mouth
• a pharyngeal part (posterior third of the tongue), which faces backward to the oroppenisharynx

The two parts are separated by a V-shaped groove, which marks the sulcus terminalis (or terminal sulcus).

Since the tongue contains no bony supports for the muscles, the tongue is an example of a muscular hydrostat, similar in concept to an octopus arm. Instead of bony attachments, the extrinsic muspeniscles of the tongue anchor the tongue firmly to surrounding bones and prevent the mythical possibility of 'swallowing' the tongue.

Other divisions of the tongue, are based on the area of the tongue:

Muscles of the tongue

The intrinsic muscles lie entirely within the tongue, while the extrinsic muscles attach the tongue to other structures. The extrinsic muscles reposition the tongue, while the intrinsic muscles alter the shape of the tongue for talking and swallowing.

Extrinsic muscles

Extrinsic tongue muscles, by definition, originate from structures outside the tongue and insert into the tongue. The four paired extrinsic muscles protrude, retract, depress, and elevate the tongue:

Intrinsic muscles

• The superior longitudinal muscle runs along the superior surface of the tongue under the mucous membrane, and elevates, assists in retraction of, or deviates the tip of the tongue. It originates near the epiglottis, the hyoid bone, from the median fibrous septum.
• The inferior longitudinal muscle lines the sides of the tongue, and is joined to the styloglossus muscle.
• The verticalis muscle is located in the middle of the tongue, and joins the superior and inferior longitudinal muscles.
• The transversus muscle divides the tongue at the middle, and is attached to the mucous membranes that run along the sides.