 Hello everyone, welcome back to another session in dentistry and world today. We have a new topic in Anatomy that is development of tongue the tongue we had covered a part of tongue We are covered in dental histology. That was about the papilla and epithelium of tongue So this video is about the development of tongue how it develops from the pharyngeal arches So regarding the pharyngeal arches this we had covered in anatomy previous session So it was a detailed Description of how the pharyngeal pouches Giving rise to the various structures in head and neck region. So this is particularly about the development of tongue So let's see the development of tongue in detail So development of tongue as we all know tongue is largest single muscular organ inside the oral cavity, which lies relatively free and The tongue develops in relation to the pharyngeal arches. So pharyngeal arches we had seen Previously pharyngeal arches. We have one two three four five pharyngeal arches and pouches and The pharyngeal clefs all we had studied in detail So this is also developed from the pharyngeal arches because most of the structures in Head and neck region is developing from the primitive pharyngeal arches So the first arch is known as mandible arch. It is always bilateral Second is hyoid arch. From mandible arch various structures like mandible, malleus, incus The second arch is known as hyoid arch The cartilage is known as Rachel's cartilage. The first arch Cartilage is known as Michael's cartilage, which give rise to various bones and ligaments So the tongue develops from pharyngeal arches mainly in two portions that is anterior two-third and posterior one-third so The anterior two-third of tongue so we need to learn few structures from which the anterior two-third develops the first one is tuberculum impar, okay, this Red color which is present in the first arch. Okay That is tuberculum impar Or you can redrawn it is here. This is a tuberculum impar this red one So it starts as a swelling in the middle of the mandibular process So this is a mandibular process for the mandibular arch So it starts as a swelling arise at the middle of the mandibular process and is flanked by two other Swillings, so these are the two swellings which is present the either side So these swellings are known as lingual swelling So the two lingual swellings and tuberculum impar which is present in the first pharyngeal arch, okay, and These lingual swellings they are present on the lateral part of the mandibular process Which are the mesenchymal thickening which develops to form The lateral sides of this tuberculum impar and ultimately the anterior two-third of tongue So these lingual swelling which merge with each other and forms a mucus membrane of anterior two-third of the tongue Okay, so lingual swellings and tuberculum impar Forms the anterior two-third and there is a structure which is known as foramen cecum which differentiate the anterior two-third and posterior one-third And these lateral swellings what happens is they quickly enlarge and Merge with each other and the tuberculum impar to form a large mass So these all will merge which these two will merge and this merge with this tuberculum impar This lingual swelling They quickly enlarge and merge with each other and then also with tuberculum impar to form a large mass From which mucus membrane of anterior two-third of the tongue is formed and this anterior two-third is supplied by Phrygium anal nerve so that will learn in detail the nerve supply and What about the posterior one-third so this is a posterior one-third Okay, this is a posterior one-third. It's a posterior one-third So this posterior one-third of the tongue arises from a large midline swelling which develops from Mason came up second third and fourth arch, okay So this anterior two-third develops only from first touch and The posterior one-third develops from second third and fourth arch. So the development of tongue involve first second third and fourth arches of Primitive farings. Okay, so it involves one two three and four arches So this has two structures, which is known as Coppola which is associated with second arch Coppola Coppola is associated with second arch and there will be a structure which is known as hypo Branquil eminence Coppola is a part of second pharyngeal arch whereas the hyperbranquil eminence is part of Third and fourth pharyngeal arch. Okay, so the posterior one-third develops from second third and fourth arch The anterior two-third develops from first touch first touch is also known as mantibular arch Okay, so posterior one-third is developing from second third and fourth arch So posterior one-third is having two structures one is known as Coppola and the hyperbranquil eminence So hyperbranquil eminence having the cranial point and caudal point cranial point is towards the head and caudal point is towards the tail and The Coppola is another structure, which is present in the posterior one-third. So what happens when the growth is happening? So this hypobranquil eminence which overgrows. Okay, so these Root of the tongue so this is a posterior one-third or root of the tongue which arises from the large midline swelling Okay, so these midline swelling so it has both Coppola and So there will be Coppola Coppola and hyperbranquil eminence, which is present in the midline at the posterior part So what happens is this hyperbranquil eminence? Which overgrows the Coppola? Which overgrows Coppola and there will be Separation from floor of the mouth. Okay, so how this separation from the floor of the mouth happens is When the tongue overgrows or this posterior one-third or the hyperbranquil eminence overgrows The ectoderm which is present at the bottom Will be degenerated. Okay, and creating lingual sulcus. So before it was a complete Mass of tissue but at the bottom point the ectoderm which is present in the peripheral will be Degenerating and creating lingual sulcus. Okay, so when lingual sulcus is created The tongue will get its mobility So tongue needs to be mobile. So there will be a degeneration of ectoderm which is present at the periphery And creating lingual sulcus. Okay So the posterior one-third is Supplied by gluosopharyngeal nerve whereas anterior one-third is separate supplied by tricheminal nerve So the muscles of the tongue which have a different origin they arise from the occipital somites which have migrated Forward in the tongue area carrying with them their nerve supply that is hypoglossal nerve So hypoglossal nerve is supplying the muscular tongue muscular hypoglossal nerve So there are lots of nerve supply involving tongue. It's taste sensation Uh General sensation So anterior third is supplied by tricheminal nerve, especially mandibular nerve posterior one-third by gluosopharyngeal Taste sensation by facial nerve so That's about the developmental part of tongue That is the anterior two-third and posterior one-third how it develops anterior two-third develops from mandibular Arch number one And posterior one-third is developed from arch number two three and four. So you need to Remember the structures which is giving rise to anterior two-third that is lingual swellings and tuberculum impar There will be two lingual swellings and Between that there will be tuberculum impar. So all this gross and Merge and forming anterior two-third and there is something called as foram and cecum So which is separating anterior and posterior one-third? So posterior one-third is developing from corpula and hyperbranquil eminence So hyperbranquil eminence over gross corpula and there will be degeneration at the bottom part which is creating lingual sulcus and providing the mobility of tongue So tongue basically has three parts. That is a root A tip and a body. Okay. So this will be the root. This is the tip and this body And the body has a Curve surface upper surface is known as the dorsal surface You cannot differentiate it because this dimension And the dorsal and the dorsal surface which has a papilla And the inferior surface or the ventral surface. Okay, which is closer to the floor of the mouth So this picture shows the oral part and the pharyngeal part of the same tongue We are separating the anterior two-third as oral part and this is a pharyngeal part of the posterior one-third sulcus terminus, which is the junction of anterior and posterior one-third And also we have a structure known as foram and cecum Which is a small midline depression at the border between these oral and pharyngeal portion of the tongue And we have at the most posterior part the epiglottis Now let's learn about the papilla of tongue So this we had covered in dental histology. Anyway, we have four types of papilla basically fungiform papilla philiform papilla folate papilla and circumvalid or valid papilla. Okay. So each papilla is a assigned Sensory function that is a taste sensation These are the projections of mucus membrane which gives the anterior two-third of the tongue its characteristics roughness So valid papilla. These are the valid papilla, which is present in front of sulcus terminus, which is the largest papilla which has blend and dead cylindrical in shape 1 to 2 millimeter in diameter number is 8 to 12 Which is occur in a v-shape Whereas a philiform papilla, which is makes the majority of papilla and covers the anterior part of tongue They appear as slender tread-like keratinized projections And it doesn't have any papilla because it is completely keratinized And these papilla facilitate mastication by compressing and breaking food when tongue is opposed to heart palate So that was the philiform papilla Next is the fungiform papilla And the next papilla is fungiform papilla, which is a mushroom shaped and more numerous Which is present near the tip and margins of tongue, but some of them are scattered all over They have smooth round structures that appear red because of their highly vascular connected tissue core And they have taste buds, okay, these taste buds seen within the epithelium Now we have foliate papilla, which is sign which is present at the side of the tongue They are leaf-like mucosal root just bilaterally at the sides of tongue near sulcus terminalis And this also has taste buds only The first one that is philiform papilla is not having any taste buds And the pharyngeal part regarding the posterior part It is lies behind the palaturglossus glosalarchus Which forms the anterior wall of auro pharynx, okay So from here we have starting the pharynx. So anterior wall of auro pharynx Which doesn't have any papillae and the mucous membrane has many lymphoid follicles that collectively Consude the lingual tonsil. So all these follicles are known as lingual tonsil And on either side it has palatine tonsils So we are talking about the dorsal surface So we have the ventral surface that is closer to the floor of the mouth It is covered by smooth mucous membrane There will be a thin strip of tissue that runs vertically from the Floor of the mouth to under surface of the tongue, which is known as lingual frenem We can feel the lingual frenem inside our floor of the mouth and tongue at the junction And it tends to limit some movement of tongue So lingual frenem is a structure which prevents tongue movement And on either side of frenem there is a prominence Which is produced by deep lingual veins Are more laterally, which is known as plicca fimbriata, okay Plica fimbriata Plica fimbriata Plica fimbriata is nothing but On either side of this frenulum, there is a prominence produced by deep lingual veins Which are more laterally And it looks like a fold, which is known as plica fimbriata, which is present on the ventral side, okay Next is arterial supply. So the main artery which supplies a tongue is lingual artery Lingual artery, which is a branch of external carotid artery, which is Reaching the tongue after passing deep to the hyoglossus muscle Which divides into dorsal lingual artery, deep lingual artery and sublingual artery, okay Which is dividing into dorsal deep lingual and sublingual arteries So this dorsal Lingual artery supplies the posterior part And the deep lingual artery supplies the anterior part And the sublingual artery supplies the submandibular gland and floor of the mouth, okay So lingual artery divides into dorsal lingual artery, deep lingual artery and sublingual artery And also we have tonsillar artery and ascending pharyngeal artery, which is supplying the most posterior part of the tongue Whereas the venous drainage, we have dorsal lingual vein, which drains the dorsum and sides of the tongue And also deep lingual veins, which drains the tip, okay, so this is a deep lingual vein Drains the tip And it joins sublingual vein from the sublingual gland, okay, so sublingual Gland is drained by sublingual vein So this deep lingual vein joins with sublingual vein, okay, this two will join And all these ultimately terminate directly or entirely into Internal jugular vein So that is about venous drainage, so we have dorsal lingual vein, which drains the dorsal part Then the deep lingual vein, which drains the tip, then it joins to sublingual vein, which was Collecting or draining the sublingual gland, it both joins and ultimately all joins to terminate in inter jugular vein Now we have nerve supple nerve supple is Supplied anterior two-third and posterior one-third So we have general sensation And also taste sensation, so the anterior two-third, the taste sensation is by corda timpani That is a branch of facial nerve, whereas the general sensation is by lingual nerve, which is a branch of mandibular nerve Which is again a branch of trigeminal nerve, okay Whereas a posterior one-third, but this doesn't include valet or circumvalent Papillae, which is the taste sensation which is present in the anterior two-third So the taste sensation is by facial nerve, that is a corda timpani nerve except Circumvalent papillae Whereas a posterior one-third, the general sensation and taste sensation is by Glosopharyngeal nerve, including the circumvalent papillae, okay And the most posterior part Is supplied by vagus nerve through internal laryngeal nerve And the muscles, regarding the muscles, all the muscles are supplied by hypoglossal nerve Except the palato Glossus muscle, which is supplied by vagus nerve, so I repeat So anterior two-third, the taste sensation by facial nerve And general sensation by lingual nerve, which is a branch of mandibular nerve, which is again a branch of trigeminal nerve So seven and five nerve numbers And the posterior one-third Glosopharyngeal nerve, general sensation and also taste sensation, including the circumvalent papillae, which is present in the anterior two-third And the Most posterior part is supplied by vagus nerve through internal laryngeal nerve And all the muscles supplied by hypoglossal nerve, except palato glossus muscle, palato glossus muscle is supplied by vagus nerve Now we have the lymphatic drainage, okay So the lymphatic drainage So the tip of tongue is drained into submental nodes and then directly to deep cervical nodes So the tip, this is a tip, it goes to Submental, submental lymph nodes Okay, submental lymph nodes, then to deep cervical node Deep Cervical node That is tip And the right and left half of the anterior two-third Trained, you need actually to submandibular node. So this is anterior two-third The right and left This goes to Submandibular node, okay Submandibular node Submandibular lymph node, so I'm talking about lymph node, okay So before we Studied arterial supply, venous supply and now supply, now we are in lymph nodes So the anterior two-third, right and left Are going into The submandibular nodes, whereas the posterior one-third, so this part Is drained directly and bilaterally to deep cervical node, okay So this directly goes to deep cervical node This is unilaterally going to right and left submandibular nodes The deep cervical nodes usually involved in jugulo-omohoid and digastic nodes. So this deep cervical nodes goes to Jugulo-omohoid and jugulo-digastic Jugulo-omohoid Or jugulo-digastic Okay So that is an lymphatic drainage Tip goes to submandibular, it goes to deep cervical node Anterior two-third, from right and left unilaterally go to submandibular Posterior one-third, bilaterally directly goes to deep cervical Deep cervical is associated with jugulo-omohoid or jugulo-digastic Now we have few developmental disturbances of tongue The first one is microglosia Microglosia, it is a rare congenital anomaly manifested by the presence of rudimentary or very small tongue The condition When tongue being completely absent is known as aglosia, okay Aglosia is a condition where the complete absence of tongue So this condition we have studied in dental histology In developmental disturbances, so classification would be True microglosia and relative microglosia So it can be corrected by auto-correction or speech and language development Microglosia is a condition when patient have an enlarged tongue, okay, microglosia Which could be associated with the Down syndrome back with Whitman syndrome And there will be associated many problems such as noise breathing, drooling, slur, speech Scaloping, open bite, cracked tongue Ankyloglosia is nothing but a condition where the tongue is fixed to the floor of the mouth That is Ankyloglosia And it can be either complete Ankyloglosia or partial So partial is known as tongue tie Tongue tie is a common condition, it is a partial Ankyloglosia So it is happening due to the short lingual freedom Or due to a freedom which attaches too near to the tip of the tongue So we know tongue is like this and lingual freedom is attached here So when it is attaching to the tip, there will be limited movements of tongue and Ankyloglosia will happen But the complete Ankyloglosia is a result of fusion between tongue and floor of the mouth So complete fusion will be there So there will not be any movement for tongue And cleft tongue is a complete cleft tongue occurs due to the lack of margin of lateral lingual feeling So when this is supposed to merge here with hypobranquil eminence When this fail to merge, there will be cleft tongue Fisher tongue is a, so that was cleft tongue And fisher tongue is a malformation manifested clinically by numerous small grooves So when this is the tongue, so there will be numerous small grooves present In the tongue Okay, on the surface of tongue So that is a fisher tongue Next we have muscles of tongue Various muscles intrinsic and extrinsic muscles of tongue Now let's see the muscles of tongue So we have two categories in muscles of tongue That is intrinsic muscles which is not attached to any bone And which alter the shape of the tongue And extrinsic muscles, they are attached to various bonds The intrinsic muscles are superior and inferior longitudinal Transverse and vertical Whereas extrinsic muscles, they are genioglossus Hyoglossus, styloglossus and palatoglossus So intrinsic muscles, they are four-paired intrinsic muscles Originate and insert within the tongue Okay, they are not attached to Anywhere else they are originated and inserted within the tongue They are four pairs And these muscles basically alter the shape of the tongue So in intrinsic muscle, the first muscle is superior longitudinal It originates in submucous fibrous layer below the dorsum of tongue and lingual septum This is a superior longitudinal It is just a diagrammatic picture on the frontal view Antirisection And insertion, it extends to the lingual margin Its action is it shortens the tongue and turns the apex and sides of the tongue upward Okay, so apex and sides of the tongue upward And it makes the dorsal surface concave Whereas inferior longitudinal This is where is inferior longitudinal This is inferior longitudinal It is an aeroband which is close to the inferior surface of tongue Its origin is root of the tongue and insertion is at apex of tongue That also action shortens the tongue Whereas it makes the dorsal convex Okay, makes the dorsal surface convex The superior longitudinal makes the dorsal surface concave Turning the upward tip of the tongue Up makes the concavity and tip the down It makes the convexity Next pair of intrinsic muscle is transverse Transverse is like this So it is a median fibrous septum And insertion is at the margin of tongue So this is the tongue means it will be inserted It is running in transverse direction Okay, so it inserted in right and left borders of the tongue Action narrows and elongates tongue Okay, so it is narrows and elongates Whereas vertical muscle fibers they originated at the anterior part of tongue Inserted at the ventral surface and borders Action flattens and broadens Okay, flattens and broadens Flattens and broadens is a function of vertical Whereas transverse function is narrowing and elongation Okay, narrowing and elongation This is just opposite functions The transverse and vertical fibers So they are the intrinsic muscles They are not attached to any bones They are just present its origin and insertion within the Insertion within the tongue Now the extrinsic muscle We have styloglossus and palatoglossus attached to tongue superiorly This is attached to tongue superiorly And genioglossus and hyoglossus attach the tongue inferiorly To the genoid bone and hyoid bone This is to the styloid process and to the palatal bone Okay, so all are attached to one bone This glossus means tongue This is attached to genoid bone This is attached to hyoid bone This is attached to styloid process This is attached to palatal bone So genioglossus So we can see the main part of tongue Genioglossus, it arises from superior Genial tubercles above the origin of geniohyd Inserted the upper fibers to tip of the tongue Upper fibers to the tip of the tongue Middle fibers to the dorsum and lower fibers to the hyoid bone And its action upper fibers retract the tip Middle fibers depress the tongue and lower fibers protrude the tongue So that is genioglossus It has upper middle and lower fibers It's starting upper fibers from tip of tongue Then middle fibers from dorsum and lower fibers from hyoid bone And its action is retracting the tip Then middle fibers depressing the tongue Lower fibers protruding the tongue And next one is styloglossus Styloglossus origin from styloid process Insertion into the longitudinal part of the inferior longitudinal muscle And function it elevates and retracts the tongue The hyoglossus muscles It is a quadrilateral shape muscle And origin from the hyoid bone Insertion into the lateral surface of tongue Function depress and retract the tongue The last one is palatoglossus It's origin from the palatine aponeurosis Insertion into the lateral margins of tongue Action elevates and elevates the posterior part of the tongue So that was about various muscles They are intrinsic and extrinsic muscles Intrinsic muscles not attached to a bone But extrinsic muscle attached to a bone So the movements of tongue The intrinsic muscles are basically involved in broadens the tongue It flattens the tongue It turns the tip upward It turns the tip downward And the sideways movement Whereas extrinsic muscles are involved in Protrusion, retraction, depression and elevation Protrusion is done by genioglossus on both sides acting together Retraction is done by styloglossus and hyoglossus on both sides Acting together Depression of tongue is done by hyoglossus and genioglossus on both sides Elevation is done by styloglossus and palatoglossus So depression and elevation You can imagine the structures which is present above the tongue and below the tongue So these are the muscles That is extrinsic muscles Involvement in the movement of tongue So that's how we complete a tongue So we learned about the development of tongue From the anterior to the third, posterior to the third All these parts, lingual swelling Tuberculum, impar, copula and hyperbranchal eminence Then we learned about the arterial supply The venous supply The lymphatic drainage The nerve supply The muscles of tongue That is intrinsic muscle and extrinsic muscles So it is a very common question You could expect the development of tongue The arterial supply Venous and lymphatic drainage could be a short knot Nerve supply could be a short knot And also the muscles, intrinsic muscles and extrinsic muscles And you may expect each one muscle as a short knot Like genioglossus Like styloglossus So I have not explained each muscle in detail So when Christian asked about single muscle You need to draw a neat label diagram And explain its origin, insertion and its action So I will come up with a new topic in anatomy Thank you