Anatomy and Structure of the Tongue
- The tongue is a muscular hydrostat in the mouth.
- It is divided into anterior and posterior parts by the terminal sulcus.
- The anterior part is visible and makes up about two-thirds of the length.
- The posterior part is closest to the throat and makes up about one-third of the length.
- The tongue has a rich blood supply.
- The tongue is divided into symmetrical halves by the median sulcus.
- The foramen cecum marks the end of the division and the beginning of the terminal sulcus.
- The terminal sulcus divides the tongue into a posterior pharyngeal part and an anterior oral part.
- The pharyngeal part is supplied by the glossopharyngeal nerve.
- The oral part is supplied by the lingual nerve for somatosensory perception and the chorda tympani for taste perception.
- The undersurface of the tongue has a fold of mucous membrane called the frenulum.
- The frenulum tethers the tongue to the floor of the mouth.
- Sublingual caruncles are small prominences on either side of the frenulum.
- The submandibular glands drain into the sublingual caruncles.
- There are eight muscles of the tongue, classified as intrinsic and extrinsic.
- The four extrinsic muscles originate from bone and extend to the tongue.
- The genioglossus muscle protrudes the tongue.
- The hyoglossus muscle retracts and depresses the tongue.
- The styloglossus muscle draws the sides of the tongue up to create a trough for swallowing.
- The tongue receives its blood supply primarily from the lingual artery.
- The lingual artery is a branch of the external carotid artery.
- The lingual veins drain into the internal jugular vein.
- The blood supply of the tongue is important for its function and health.
- Proper blood circulation ensures the tongue remains sensitive and moist.
Nerve Supply and Lymphatic Drainage
- The mouth receives blood supply from the lingual artery.
- The root of the tongue also receives blood supply from the tonsillar branch of the facial artery and the ascending pharyngeal artery.
- The Pirogov triangle in the neck is formed by the intermediate tendon of the digastric muscle, the posterior border of the mylohyoid muscle, and the hypoglossal nerve.
- Severe hemorrhage from the tongue can be stopped at the lingual artery.
- Motor supply for all intrinsic and extrinsic muscles of the tongue is from the hypoglossal nerve (CN XII), except for the palatoglossus which is innervated by the vagus nerve (CN X).
- Taste and sensation in the anterior two-thirds of the tongue are innervated by the chorda tympani branch of the facial nerve (CN VII) and the lingual branch of the mandibular (V3) division of the trigeminal nerve (CN V), respectively.
- Taste and sensation in the posterior one-third of the tongue are innervated by the glossopharyngeal nerve (CN IX).
- Taste and sensation in the base of the tongue are innervated by the internal branch of the superior laryngeal nerve (a branch of the vagus nerve, CN X).
- The tip of the tongue drains to the submental nodes.
- The anterior two-thirds of the tongue drains to submandibular lymph nodes.
- The posterior one-third of the tongue drains to the jugulo-omohyoid nodes.
- The lymphatic drainage pattern differs based on the location of the tongue.
Microanatomy and Development
- The upper surface of the tongue is covered in masticatory mucosa, a type of oral mucosa.
- The tongue has different types of lingual papillae, including filiform, fungiform, vallate, and foliate papillae.
- Taste buds are housed in some of the lingual papillae.
- The dorsal surface of the tongue is stratified squamous keratinised epithelium with numerous mucosal projections called papillae.
- The ventral surface of the tongue is stratified squamous non-keratinised epithelium.
- The tongue begins to develop in the fourth week of embryonic development from the median tongue bud of the first pharyngeal arch.
- Lateral lingual swellings form on the first pharyngeal arch and cover the median tongue bud, forming the anterior part of the tongue.
- The copula from the second pharyngeal arch and the hypopharyngeal eminence from the third and fourth arches contribute to the development of the posterior part of the tongue.
- The boundary between the anterior and posterior parts of the tongue is marked by the terminal sulcus.
- The terminal sulcus is shaped like a V, with the tip situated posteriorly and contains the foramen cecum.
Function of the Tongue
- The tongue is equipped with taste buds that can sense different classes of tastes.
- Different sections of the tongue are not exclusively responsible for different basic tastes.
- The tongue plays a role in mastication by crushing food against the hard palate.
- The tongue is one of the primary articulators in speech production.
- The tongue is involved in physical intimacy and sexuality.
- The tongue can have various conditions, such as black hairy tongue, bifid tongue, and fissured tongue.
- Oral cancer, mainly squamous cell carcinomas, can affect the tongue.
- A visible tongue coating, formed by food debris, desquamated epithelial cells, and bacteria, can contribute to bad breath.
- Using a tongue cleaner can help manage bad breath caused by the tongue coating.
- The sublingual region underneath the front of the tongue is ideal for the administration of certain medications, bypassing the gastrointestinal tract.
Tongues in Other Animals, Society and Culture, Gestures, Tongue in Food and Body
The tongue is a muscular organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by taste buds housed in numerous lingual papillae. It is sensitive and kept moist by saliva and is richly supplied with nerves and blood vessels. The tongue also serves as a natural means of cleaning the teeth. A major function of the tongue is the enabling of speech in humans and vocalization in other animals.
Tongue | |
---|---|
Details | |
Precursor | pharyngeal arches, lateral lingual swelling, tuberculum impar |
System | Alimentary tract, gustatory system |
Artery | lingual, tonsillar branch, ascending pharyngeal |
Vein | lingual |
Nerve | Sensory Anterior two-thirds: Lingual (sensation) and chorda tympani (taste) Posterior one-third: Glossopharyngeal (IX) Motor Hypoglossal (XII), except palatoglossus muscle supplied by the pharyngeal plexus via vagus (X) |
Lymph | Deep cervical, submandibular, submental |
Identifiers | |
Latin | lingua |
MeSH | D014059 |
TA98 | A05.1.04.001 |
TA2 | 2820 |
FMA | 54640 |
Anatomical terminology |
The human tongue is divided into two parts, an oral part at the front and a pharyngeal part at the back. The left and right sides are also separated along most of its length by a vertical section of fibrous tissue (the lingual septum) that results in a groove, the median sulcus, on the tongue's surface.
There are two groups of muscles of the tongue. The four intrinsic muscles alter the shape of the tongue and are not attached to bone. The four paired extrinsic muscles change the position of the tongue and are anchored to bone.
From Middle English tonge, tunge, tung, from Old English tunge, from Proto-West Germanic *tungā, from Proto-Germanic
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