Presented by :- Dr. Aditya ShindeGuided by :- Dr. Lalitagauri Mandke

( 1 - 70 )

Introduction

Definition

Functions

External features of tongue

Histology

Medical Anomalies

Tongue is the sense organ that gives satiety

It also helps is articulation It is also a mirror reflecting various

systemic diseases

A fleshy movable muscular process of the floor of the mouth of the most vertebrates that bears the sense organ and small glands and functions in talking and swallowing

Mass of striated muscles covered with the mucous membrane

Divided into right and left halves by a median septum

Three parts: Oral (anterior ⅔) Pharyngeal (posterior

⅓) Root (base)

Two surfaces: Dorsal Ventral

Divided into anterior two third and posterior one third by a V-shaped sulcus terminalis.

The apex of the sulcus faces backward and is marked by a pit called the foramen cecum

Foramen cecum, an embryological remnant, marks the site of the upper end of the thyroglossal duct

Anterior two third: mucosa is rough, shows three types of papillae: Filiform Fungiform Vallate

Posterior one third: No papillae but shows nodular surface because of underlying lymphatic nodules, the lingual tonsils

Smooth (no papillae) In the midline

anteriorly, a mucosal fold, frenulum connects the tongue with the floor of the mouth

Lateral to frenulum, deep lingual vein can be seen through the mucosa

Lateral to lingual vein, a fold of mucosa forms the plica fimbriata

Root: It is attached to the

mandible and soft palate above and the hyoid bone below. Because of these attachments, we are not able to swallow the tongue itself.

In between the two bones, it is related to geniohyoid and mylohyoid muscles.

TASTE Salt Sweet Sour Bitter umami

Chewing Swallowing cleansing

The tongue is the most important articulator for speech production

The primary function of the tongue is to provide a mechanism for taste. Taste buds are located on different areas of the tongue, but are generally found around the edges. They are sensitive to four main tastes: Bitter, Sour, Salty & Sweet

The tongue is needed for sucking, chewing, swallowing, eating, drinking, , sweeping the mouth for food debris and other particles.

Trumpeters and horn & flute players have very well developed tongue muscles, and are able to perform rapid, controlled movements or articulations

FUNCTIONS in brief :FUNCTIONS in brief :

Extrinsic Muscles Intrinsic Muscles

Genioglossus superior longitudinal

Hyoglossus inferior longitudinal Styloglossus tansverse

Chondroglossus vertical

Palatoglossus

It is triangular in sagittal section, lying near and parallel to the midline.It arises from a short tendon attached to the superior genial tubercle behind the mandibular symphysis, above the origin of geniohyoid. From this point, it fans out backwards and upwards.

BLOOD SUPPLY: Sublingual branch of the Lingual artery. Submental branch of the Facial artery.

NERVE SUPPY Hypoglossal nerve.

Acting bilaterally, they depress the central part of the tongue, making it concave from side to side.

Acting unilaterally, the tongue diverges to opposite side

Protrude the apex

It is thin and quadrilateral.

It arises from the whole length of the greater cornu and

the front of the body of the hyoid

bone.It passes vertically up to enter the side

of the tongue between

Styloglossus laterally and the

inferior longitudinal muscle medially.

Vascular Supply Sublingual branch of the Lingual artery. Submental branch of the Facial artery.

Innervation Hypoglossal nerve.

Actions It depresses the tongue.

It is sometimes described as a part of Hyoglossus and is separated from it by some fibers of Genioglossus.

It is 2 cm long, arising from the medial side and base of the lesser cornu and the adjoining part of the body of the hyoid.

It ascends to merge into the intrinsic musculature between Hyoglossus and Genioglossus muscle.

It is the shortest and smallest of three styloid muscles.

It arises from the anterolateral aspect of the styloid process near its apex and from the styloid end of the stylomandibular ligament.

it passes downwards and forwards and divides at the side of the tongue into a longitudinal part, which enters the tongue dorsolaterally to blend with the inferior longitudinal muscle in front of Hyoglossus and an oblique part, which overlap Hyoglossus and decussate with it.

Vascular Supply Sublingual branch of the Lingual artery.

Innervation Hypoglossal nerve.

Action It draws the tongue up and backward.

It is narrower at its middle than at its end.

It is closely associated with soft palate in function and innervation.

Together with its overlying mucosa, it forms the palatoglossal arch.

It arises from the oral surface of the palatine aponeurosis where it is continuous with its fellow.

It extends forwards, downwards and laterally in front of the palatine tonsil to the side of the tongue.

Vascular Supply Ascending palatine branch of Facial artery. Ascending pharyngeal artery.

Innervation Cranial part of the accessory nerve via the pharyngeal

plexus.

Actions Elevates the root of the tongue and approximates the

palatoglossal arch to its contralateral,shutting off the oral cavity from the oropharynx.

Superior longitudinal

It constitutes a thin stratum of oblique and longitudinal fibers lying beneath the mucosa of the dorsum of the tongue.It extends forwards from the submucous fibrous tissue near the epiglottis and from the median lingual septum to the lingual margins

Inferior longitudinal

It is a narrow band of muscle close to the inferior lingual surface between Genioglossus and Hyoglossus.It extends from the root of the tongue to apex.Some of its posterior fibers are connected to the body of the hyoid bone.

Transverse

They pass laterally from the median fibrous septum to the submucous fibrous tissue at the lingual margin, blending with palatopharyngeus.They extend from the dorsal to the ventral aspect of the tongue in the anterior borders.

Vascular Supply – Lingual artery.

Innervation – Hypoglossal nerve.

The intrinsic muscles alter the shape of the tongue. Contraction of superior and inferior longitudinal muscles

tends to shorten the tongue. The transverse muscle narrows and elongates the tongue.

The vertical muscle flattens and widens the tongue

Anterior ⅔: General sensations:

Lingual nerve Special sensations :

chorda tympani

Posterior ⅓: General & special

sensations: glossopharyngeal nerve

Base: General & special

sensations: internal laryngeal nerve

Intrinsic muscles: Hypoglossal nerve

Extrinsic muscles: All supplied by the

hypoglossal nerve, except the palatoglossus

The palatoglossus supplied by the pharyngeal plexus

Arteries: Lingual artery Tonsillar branch of

facial artery Ascending

pharyngeal artery Veins:

Lingual vein, ultimately drains into the internal jugular vein

Hypoglossal nerve

Lingual artery & vein

Deep lingual vein

Dorsal lingual artery & vein

Tip: Sub mental nodes

bilaterally & then deep cervical nodes

Anterior two third: Submandibular

unilaterally & then deep cervical nodes

Posterior third: Deep cervical nodes

(jugulodigastric mainly)

skeletal muscle supported by connective tissue.

The mucous membrane differs in its structure.

Dorsal Lingual Mucosa

Thicker, no sub mucosa covered by numerous

papillae.

stratified squamous epithelium

Non-keratinized posteriorly / fully keratinized

overlying the filliform papillae anteriorly.

4 principal types – Filiform papillae Fungiform papillae Foliate papillae Circumvallate

papillae

1.1. Filiform papilla:Filiform papilla: Makes up majority of the papillae and covers the anterior partof the tongue. They appear as slender, threadlike keratinized projections(~ 2 to 3 mm) of the surface epithelial cells. These papillae facilitate mastication(by compressing and breaking food when tongue is apposed to the hard palate) and movement of the food on the surface of the tongue. The papillae is directedtowards the throat and assist in movement of food towards that direction. NO TASTE BUDS.

FILLIFORM PAPILLA

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2.2. Fungiform papillaFungiform papilla: (Fungus-like) These are interspersed between the filiform papilla.More numerous near the tip of the tongue. Smooth, round structures that appearred because of their highly vascular connective tissue core, seen through a thin,nonkeratinized stratified squamous epithelium. Taste buds are usually seen withinthe epithelium.

Filiform papilla

FUNGIFORM PAPILLA

3.3. Foliate PapillaFoliate Papilla: (Leaf-like). Present on the lateral margins of the posterior tongue.Consist of 4 to 11 parallel ridges that alternate with deep grooves in the mucosa,and a few taste buds are present in the epithelium. They contain serous glandsunderlying the taste buds which cleanse the grooves.

FOLIATE PAPILLAEFOLIATE PAPILLAE

4.4. Circumvallate papillaCircumvallate papilla: (Walled papilla). 10 to 14 in number these are seen alongthe V-shaped sulcus between the base and the body of the tongue. Large, ~ 3 mmin diameter with a deep surrounding groove. Ducts of von Ebner glands (seroussalivary glands) open into the grooves. Taste buds are seen lining the walls ofthe papillae.

CIRCUMVALLATE PAPILLACIRCUMVALLATE PAPILLA

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Unique sense organs that contain the chemical sense for taste Microscopically visible barrel-shaped bodies found in the oral epithelium . Usually associated with papillae of the tongue (circumvallate, foliate and fungiform). Also seen in soft palate, epiglottis, larynx, and pharynx . Referred to as NEUROEPITHELIAL STRUCTURES. But most correctly referredas epithelial cells closely associated with clib-shaped sensory nerve endings. Thesenerves arise from the chorda tympani in anterior tongue and glossopharyngeal inposterior tongue and come to lie among the taste cells. Each taste bud has ~ 10 to14 cells. Majority are taste cells with elongated microvilli that project into thetaste pore. (Epiglottis and larynx – Vagus nerve)

Type 1 dark cell (60% of cells)Type 2, light cells (30%)Type 3 (7%) and Type 4 (basal cells ~ 3%)

TASTE BUDSTASTE BUDS

all that can be seen from the surface, even with a scanning electron microscope, is a small hole, the taste pore, through which the sapid substance must pass

Supporting cells - contain microvilli, appear to secrete substances into lumen of taste bud.

Sensory receptor cell - has peg-like extensions projecting into lumen. These contain the sites of sensory transduction.

Basal cells - these differentiate into new receptor cells. They are derived from surrounding epithelium. The cells are continuously renewed every 10 days or so.

composed of elongated sensory cells arranged with other nonsensory cells like the segments of an orange

The apical portions of the sensory cells have microvilli that project into the region of the taste pore. These microvilli are 2 to 5 µm long and 0.05 to 0.2 µm wide, and function perhaps to increase the surface area of the cell membrane

The surface of the taste buds is composed of cell membrane with lipid bilayer. When taste substances are adsorbed with the membrane, the electric characteristics such as electric potential change. It is thought that the changes of membrane potential are obtained from various taste buds and neural network calculates them by pattern recognition.

Cranial nerves carry taste information into the brain to a part of the brain stem called the nucleus of the solitary tract.

From the nucleus of the solitary tract, taste information goes to the thalamus and then to the cerebral cortex.

Like information for smell, taste information also goes to the limbic system(hypothalamus and amygdala).

New taste buds are produced every three to ten days to replace the ones worn out by scalding or frozen foods

Location of Taste Buds Innervation

Anterior part of tongue excluding vallate papillae

Chorda tympani via lingual nerve

Inferior surface of the soft palate

Facial nerve, greater petrosal nerve, pterygopalatine

ganglion and lesser palatine nerve.

Circumvallate papillae, Postsulcal part of tongue, palatoglossal arches and

oropharynx.

Glossopharyngeal nerve.

Extreme pharyngeal part of the tongue

Internal laryngeal branch of vagus nerve.

The complete inability to taste is called ageusia, the reduced ability to taste is called hypogeusia, and the enhanced ability to taste is called hypergeusia. Ageusia is a rare disorder

MICROGLOSSIA

This is a condition where the size of the tongue is abnormally small. Cases of complete absence of the tongue have been reported. Fortunately, it is a rare condition. Obviously, a tiny tongue will pose many difficulties related to speech and swallowing. There is no treatment for this condition, and the affected person will have to train their tongue to the best of their abilities.

This is a much more common condition than microglossia, where the tongue is highly enlarged. An enlarged tongue may be congenital, when it is associated with generalized muscular hypertrophy or hemi hypertrophy.

As a rule, macroglossia causes disturbances in the teeth as well. Due to the continuous pressure exerted by the heavy tongue, teeth begin to move away and the tongue occupies these spaces between the teeth, giving it a scalloped appearance. 

The treatment of macroglossia involves the removal of the cause that gives rise to this condition. At times, surgical stripping of the tongue to reduce the heavy musculature is also warranted. 

This condition is also referred to as scrotal tongue since the tongue often resembles the scrotum in this state. Here a transverse groove is present on the tongue from which numerous smaller grooves radiate all over the surface of the tongue. The condition is usually painless and the only problem is with the food debris gets stuck in the grooves. These have to be cleaned by gauze or a toothbrush.

Ankyloglossia occurs as a result of the fusion of the lingual frenum to the floor of the mouth. However, complete fusion rarely occurs; a partial ankyloglossia or "tongue-tie" is a much more common condition. This leads to a myriad of speech problems such as lisping and stuttering. The treatment is to surgically sever the connection between the frenum and the floor of the mouth. 

This condition is a classic developmental disorder of the tongue. It is a failure of the developmental apparatus during the organogenesis of the fetus. A structure called "tuberculum impar" is supposed to withdraw when the two halves of the tongue come close to each other during development. When this does not happen, the structure gets trapped in between the two halves of the tongue, thereby creating an area, which looks like a bald patch on it. Median Rhomboid Glossitis has also been strongly linked with the fungal infection caused by Candida albicans, where the tongue has an ovoid patch just before the entry into the esophagus. This condition is reportedly thrice as common in men as in women. The exact cause for this occurrence is not known, although hormonal links have been suggested.

There is no known treatment for MRG, though doctors have tried to administer anti-fungal agents with mixed results

Cleft tongue is a condition where the tongue has a cleft running right across it horizontally or vertically, although reported cases have had vertical clefts. Complete clefting is extremely rare, and occurs as a result of lack of developmental forces to push both halves of the tongue towards each other. Partial clefting presents as a deep groove in the middle of the tongue and is a common feature in the oro-facial-digital syndrome. Cleft tongue is of little importance other than causing difficulty in eating as food

gets stuck in the cleft. 

This condition is also called a Geographic Tongue due to the behavior of the lesions, which tend to "migrate" from one area of the tongue to another. The exact cause for the condition remains unknown, although it tends to occur with more intensity in cases of emotional stress. Females are twice as affected as males, but no racial differences have been observed. The lesions here are yellowish-white or deep red in color depending on the papillae that are affected. Patients with this condition are usually asymptomatic and the lesions themselves are an incidental finding during routine check-up. Again there is no known treatment for the disease, but some doctors have reported moderate success with vitamins and mineral supplements.

This is a condition characterized by the hypertrophy of the filiform papillae of the tongue as well as desquamation of the area where this occurs. If the papillae become stained with tobacco, they appear black in color and look like hair on the tongue. The tongue could also appear yellowish-white if foodstuff is trapped within these papillae. Anemia and gastric troubles are said to have a significant bearing on the development of this condition. Antibiotics like penicillin and Aureomycin are also responsible for the staining of the papillae. Sometimes, head and neck irradiation after cancer may also produce this condition. The only treatment of the condition is to keep the tongue as clean as possible by using a toothbrush.

A common HIV-related infection is called candidiasis. Symptoms include inflammation of and a white film on the tongue. Another viral infection that affects the mouth is oral hairy leukoplakia, which causes white lesions on the tongue.

A tongue piercing is a body piercing usually done directly through the centre of the tongue.

Standard tongue piercing or one hole in the centre of the tongue is the most common and safest way to have your pierced .According to Canadian Dental Association infection are the most common generalized complication of tongue piercing with an estimate 20% infection rate of intraoral piercing.

It can cause: bleeding , drooling , nerve damage,pain, swelling , allergic reaction.

The tongue jewellery knocks into the teeth and gum tissue, causing teeth to crack, chip or break , damage to the fillings and other restoration and damage to gum tissue.

Tongue is a strong muscle that is anchored to the floor of the mouth and it has the organs of taste reception.

It is associated with the functions of taste , speech , mastication and deglutition.

Papillae are the projections of mucous membrane or corium which gives the anterior two-third of the tongue its characteristic roughness.(filiform,fungiform,vallate).

Tongue appears very mobile still it cannot be swallowed like food because tongue is anchored to hyoid bone , mandible and soft palate with attachment of three extrinsic and four intrinsic muscle.

Thanks to the taste buds that the multiple hotels, restaurants, fast food outlets, chat-pakori shops etc. are flourishing.

1. Gray’s Anatomy For Students: -Richard LD Rake, Wayne Vogl 1st

Ed, chapter 8 Conceptual overview of head and neck, Regional

anatomy, oral cavity- tongue page 989- 996.

2. Shafer’s Text Book Of Oral Pathology – 5th Ed ; Shafer, Hine, Levy,

Section-1, Disturbance of development and growth, R. Rajenrda,

page35-44.

3. B.D. Chauraisa’s human anatomy; Regional And Applied Dissection

and Clinical 4th Ed Vol-3 section-1 chapter-17 “The Tongue” page

249-254.

4. Ten Cate’ oral histology

7. Color atlas of dental medicine – Periodontology ; Herbert. F.

Wolf, Edith. M, Klaus H. Rate’s; 3rd Ed; chapter- Therapy,

Phase-I therapy page237.

8. De Moor RJG, De Witte AMJC, De Bruyne MAA. “Tongue piercing and associated oral and dental complications”  Endod Dent Traumatol 2000; 16: 232–23