Tongue: anatomy, location and function

Tongue (lingua) is a muscular organ in the floor of the mouth, with a mobile oral part and a posterior part extending into the throat. It moves food during chewing and swallowing, contributes to speech, and carries receptors for taste and general sensation, including touch and temperature.

Where is the tongue located?

The oral part of the tongue lies within the arch of the lower jaw, beneath the palate, which forms the roof of the mouth. Its mobile tip and body occupy the oral cavity, the space inside the mouth. Its root attaches it to neighbouring structures and extends towards the oropharynx, the part of the throat behind the mouth.

The teeth and gums surround its front and sides. Below it are the muscles of the floor of the mouth, including mylohyoid, which forms a muscular support beneath the tongue. The hyoid bone, a bone in the upper neck, provides attachment for several muscles associated with tongue movement.

Behind the tongue lies the epiglottis, a flap of cartilage at the entrance to the larynx, or voice box. Folds of mucosa, the moist tissue lining the mouth and throat, connect the tongue to the epiglottis.

What are the parts and surfaces of the tongue?

The tongue has a tip, or apex, a body and a root. The superior surface of tongue, also called the dorsum, faces the palate anteriorly and the throat posteriorly. A shallow midline groove marks much of its oral portion.

A V-shaped groove called the sulcus terminalis separates the oral part from the posterior part of tongue, which faces the oropharynx. At the point of this groove is the foramen caecum, a small blind pit marking the embryonic origin of the thyroid gland.

The inferior surface of tongue is smoother than the upper surface. A midline fold called the lingual frenulum connects it to the floor of the mouth. Veins can be visible beneath its thin mucosa.

The posterior surface contains the lingual tonsil, a collection of lymphoid tissue involved in immune defence. Unlike the oral surface, this region has an irregular appearance largely because of that underlying tissue.

What are tongue papillae, and which contain taste buds?

Papillae are small projections of the tongue’s mucosa. Taste buds are groups of specialised sensory cells that detect dissolved substances. Not every type of papilla contains taste buds.

• Filiform papillae are slender projections covering much of the oral dorsum. They provide friction for handling food and do not contain taste buds.
• A fungiform papilla is a rounded projection found especially near the tip and sides. This type contains taste buds.
• A vallate papilla is a larger projection surrounded by a trench. These papillae form a row just in front of the sulcus terminalis, with taste buds in their walls.
• Foliate papillae are folds along the posterolateral margins, meaning the back portions of the sides. They also contain taste buds.

Taste qualities are not confined to separate, sharply bounded zones of the tongue.

How do the tongue muscles work?

The tongue contains interlacing skeletal muscle fibres, the contractile tissue used for voluntary movement. A fibrous partition called the lingual septum separates the right and left sides internally. The muscles are grouped by whether they lie entirely within the tongue or connect it to surrounding structures.

Intrinsic muscles, which lie within the tongue, change its shape. The superior and inferior longitudinal muscles shorten it and curl its tip; the transverse muscle narrows and elongates it; the vertical muscle flattens and broadens it.

Extrinsic muscles connect the tongue to other structures and mainly change its position:

• Genioglossus arises from the inner surface of the lower jaw and draws the tongue forwards.
• Hyoglossus arises from the hyoid bone and depresses the tongue.
• Styloglossus arises from the styloid process, a bony projection beneath the skull, and draws the tongue backwards and upwards.
• Palatoglossus extends from the soft palate, the muscular posterior part of the palate, to the tongue and elevates its posterior region.

Together, these muscles reposition food, form a bolus—a cohesive mass of chewed food—and push it towards the throat. They also shape airflow and contact the palate or teeth to articulate speech sounds.

What supplies blood to the tongue, and where does lymph drain?

The lingual artery, a branch of the external carotid artery in the neck, provides the main arterial supply. Its branches supply the posterior region, tongue substance and underside. The ascending pharyngeal artery also contributes to the posterior region.

The lingual vein drains blood from the tongue towards the internal jugular vein, a major vein of the neck.

Lymph, fluid collected from tissues, drains through lymphatic vessels to lymph nodes. The tip drains mainly to submental nodes beneath the chin; the lateral oral regions drain mainly to submandibular nodes beneath the jaw. Central oral regions and the posterior region drain to deep cervical nodes along the internal jugular vein. Drainage can cross the midline, particularly from central and posterior regions.

Which nerves supply the tongue?

Motor supply activates muscles; general sensory supply carries sensations such as touch, pain and temperature. Taste has separate sensory pathways. Cranial nerves are nerves connected directly to the brain.

The small tongue region immediately adjacent to the epiglottis receives sensory and taste fibres through the internal laryngeal branch of the vagus nerve.

How can you locate the tongue in the 3D model?

In the 3D model next to this article, rotate and zoom around the mouth, then select the tongue and isolate it. Switch layers on and off to compare its position with the lower jaw and neighbouring structures. A sagittal section, a cut in a plane dividing right from left, can help orient its relationship to the palate and throat.