4. Oral Cavity anatomy ,vasculation and lympatic drainage

A brief description of the structure of the oral cavity

1. ORAL CAVITY, TONGUE AND PALATE

2. Oral Cavity (Mouth) ⦿ Exte n d s fro m t h e l i p s t o t he oroph a r y ng e a l isthmus The oroph a r y ng e a l isthmus: I s th e j u ncti o n o f mou t h and pharynx. I s bou n de d : Above b y th e sof t p a l ate an d th e pa l ato g lossa l fo l ds Be l o w b y th e dorsu m o f t h e tongue ⦿ Subdivided into Vestibule & Oral cavity proper

3. Oral Cavity (Mouth)

4. Vestibule ⦿ S l it l ik e spac e betwe e n th e cheek s a n d th e gums ⦿ Communicates with the exterior thro u g h th e ora l fissure ⦿ Wh e n th e jaw s ar e closed, commun i cate s with th e ora l c avity prop e r be h i n d th e 3 r d mo l a r to o t h on eac h s ide ⦿ Superiorly and inferiorly limited by the refl e ctio n o f mucou s membra n e from l i p s an d chee k ont o th e gums

5. Vestibule cont’d ⦿ The la t era l wall o f t h e v estib u l e is form e d b y th e c he e k – The cheek is composed of B u c c in a to r muscle , cove r ed l a tera l l y b y th e ski n & me d i a l l y b y th e mucou s mem b rane ⦿ A smal l pa p i l l a o n th e m u cosa op p osit e th e up p e r 2 n d mo l a r to o th mark s th e op e ni n g o f th e duc t of th e paroti d gl a nd

6. Oral Cavity Proper ⦿ I t i s th e cavit y wit h i n th e alveo l ar margi n s o f th e maxi l la e an d the mandible It s Ro o f i s form e d b y th e hard palate anteriorly and the soft palate posteriorly It s Floor i s forme d b y th e mylohyo i d muscl e . The anterio r 2/3 r d o f t h e to n gu e l i e s o n th e fl o o r . ha r d soft palate mylohyoid

7. Floor of the Mouth ⦿ Co vere d with mucou s membrane ⦿ I n th e mid l ine , a mu c osa l fold , the frenulu m , connect s th e tong u e t o the floo r o f th e mouth ⦿ O n eac h sid e o f frenulu m a small papi l l a ha s th e op e ni n g o f t h e duc t of th e submandibula r gland ⦿ A rounded ridge extendin g bac k ward & laterall y fro m th e papi l l a i s produ c ed b y t h e subl i ng u a l gl a nd

8. Nerve Supply Sensory Roof : by greater palatine and nasopalatine nerves (branches of maxi l l a ry nerv e ) Floor : by lingual nerve (branch of mandibular nerve ) Cheek : by buccal nerve (branch of mandibular nerve ) Motor Muscle in the cheek ( buccinator ) and the lip ( orbicularis oris ) are supplied by the branches of the facial nerve

9. Lips They ar e 2 mobi l e musculof i brou s fo l d s that sur r ou n d t h e ope n i n g o f th e mou t h The upper and lower lips meet laterally at the angle of the mouth(usually infront of the 1 st premolar) Li p s ar e l i ne d b y s k i n external l y and in t erna l l y b y mucou s mem b rane

10. Structure & blood supply of the lip From superficia l t o d eep Skin S u perfici a l fascia O r bicu l ari s ori s muscle S u bm u cos a cont a i n i n g mucu s g l and Mucu s mem b rane B l oo d supp l y t o t h e l i ps Each lip is supplied by labial branches of facia l arter y . E a c h l i p ha s a n arteri a l arc h form e d b y the end-on anastomosis btwn labial branches o f t h e fa c ia l arteries.

11. L ymphatics to the lips The lympha t ic s fro m th e centra l par t o f th e l o wer l i p drai n int o submen t a l lymp h no d e s . The lymphatics from lateral parts of lower lip & who l e o f uppe r l i p drai n in t o subman d ib u la r lymph nodes. Ner v e Supply to the lips hav e ri c h sen s or y s uppl y fro m trigemina l ner v e. The upper lip is supplied by labial branches of the in f raorbit a l nerv e (a branc h o f m a xil l ar y divisi o n) l o wer l i p b y th e me n ta l nerv e ( a branc h of man d ib u la r divisi o n o f t h e t r ig e mi n a l nerve). The red p o rtions o f l i p ar e hi g hl y sensitiv e and represented by a large area in the sensory cortex of cerebra l hem i sphere

12. THE CHEEKS are fleshy flaps forming a large part of the face. Each cheek is continuous in front with the lip. The junction between the two is marked by the nasolabial sulcus or the nasolabial furrow, which extends from the side of the nose to the angle of the mouth. cheeks are lined externally by the skin and internally by the mucus membrane.

13. Layers of the Cheek From superficial to deep, the layers of the cheek are as follows: Skin. Superficial fascia containing some muscles of facial expression, viz. zygomaticus major, risorius. Buccal pad of fat. Buccopharyngeal fascia. Buccinator muscle between the alveolar processes of both jaws. Submucosa containing buccal (mucus) glands. Mucus membrane

14. GUMS (GINGIVA) The gums are composed of fibrous tissue covered with a smooth vascular mucous membrane. They envelop the alveolar processes of the jaws & necks of the teeth. Parts of Gum:- free gingiva- surrounds the neck of tooth like a collar. Attached gingiva- firmly attached to the alveolar process. Interdental gingiva- extension of the attached gingiva between the teeth.

15. Nerve Supply to gums Upper gums on: T he lab i a l aspec t ar e supplie d b y t he posterior, middle, & anterior-superior alveo l a r nerve s , T he l i ngua l aspec t ar e supplie d b y t he greate r palat i n e & nasopalat i n e nerves. Lower gums on: T he lab i a l aspec t ar e supplie d b y buccal branc h o f mandibu l a r nerv e & inc i sive branc h o f m enta l nerve T he l i ngua l aspec t ar e supplie d b y t he l i ngua l nerves

16. Clinical correlate Gingivitis: The improper oral hygiene may cause inflammation of gums (gingivitis) & suppuration with formation of pockets of pus between teeth and gums leading to clinical condition called pyorrhea It clinically present as: discharge of pus at the margins of gums foul smell during breathing. Scurvy: In scurvy due to deficiency of vitamin C the gums become swollen, spongy, and

17. T ongue ⦿ Mas s o f st r ia t e d mus c le s co v ered with th e m u cou s me m brane ⦿ Divid e d in t o r ig h t an d le f t ha l ve s b y a me d i a n sept u m ⦿ Three p a rt s : O r a l (anteri o r ⅔ ) P h arynge a l (posteri o r ⅓ ) Root ( base) ⦿ T wo surfaces: Dorsal Ventral

18. Dorsal Surface ⦿ Divided into anterior two third and posterior one third by a V-shaped sulcus terminalis . ⦿ The apex of the sulcus faces backward and i s marke d b y a p i t call e d th e fora m e n cecum ⦿ Foramen c ecum , a n e mbryolog i ca l remnant, mark s th e sit e o f th e uppe r en d o f the thyrog l ossa l duct

19. Dorsal Surface cont’d ⦿ A n teri o r tw o third : mucos a is rough, show s thre e t ype s of papillae: Filliform Fungiform Vallate ⦿ P o sterio r on e th i r d : No papi l lae bu t s how s no d ul a r surfa c e beca u s e o f und e rlying lymph a ti c no d ul e s , th e l i ng u al tonsils

20. Ventral Surface ⦿ Sm o ot h (no pa p i l la e ) ⦿ In the midline anteriorly, a mucosal fold, frenu l u m connect s th e ton g u e with the fl o o r o f t h e mo u th ⦿ Lateral to frenulum, deep lingual vein ca n b e s ee n throu g h th e mucosa ⦿ La t era l t o li n gu a l vei n , a f o l d o f mucosa form s th e pl i c a fim b riata

21. Mus c les ⦿ The t o ng u e i s compose d o f two type s o f muscles: Intrinsic Extrinsic

22. Intrinsic Muscles ⦿ Co n fi n e d t o t on g ue ⦿ No bon y att a chment ⦿ Co n sis t of: Longitud i na l fibers T rans ve r s e f ibers V ertica l fibers Functio n : A l te r th e s ha p e o f the tongue

23. Extrinsic Muscles ⦿ Conn e c t th e ton g u e t o t h e s urround i ng structures : th e sof t p a l at e an d th e bones (mandi b le , hyoi d bon e , st y lo i d p r oces s ) ⦿ Inclu d e: Palatoglossus Genioglossus Hyoglossus Styloglossus ⦿ Functio n : Help i n movement s o f the tongue

24. Movements Protrusion : Geni o gl o s s u s o n b ot h s id e s actin g tog e ther Retraction : S t ylo g l o s s u s an d hyog l ossu s o n bot h sid e s actin g tog e ther Depression: Hyoglossus and genioglossus on both sides actin g tog e ther Elevation : Styloglossus and palatoglossus on both sides actin g tog e ther

25. Sensory Nerve Supply e ⦿ A n terio r ⅔: Gen e ral s ensa t i o ns : L i ng u a l nerv S p ecia l sensatio n s : chorda tympani ⦿ P o sterior Genera l & specia l sensatio n s: g l ossoph a r y ng e a l nerve ⦿ B a se: Genera l & specia l sensatio n s: i n tern a l l a r y ng e a l nerve

26. Motor Nerve Supply ⦿ Intr i nsi c muscles: Hypogl o s s a l nerve ⦿ Extri n si c muscles: A l l suppl i e d b y th e hypog l ossal nerve , except the palatoglossus ⦿ The pa l ato g lossu s suppl i e d b y the ph a r y ng e a l p l exus

27. Blood Supply Arteries : L i ng u a l artery T onsi l la r branc h o f f a cial artery Ascendi n g ph a r y ng e a l artery Veins : L i ng u a l vei n , ult i ma t e l y dra i ns in t o th e in t erna l ju g ul a r vein H y poglossal nerve Lingual artery & vein Deep lingual vein Dorsal lingual artery & vein

28. Lymphatic Drainage Tip: Submental nodes bilaterally & the n de e p c ervica l no d es A n terio r tw o third: S u bma n di b ul a r un i la t eral l y & th e n dee p cer v ica l no d es P o sterio r th i rd: – Deep ce r vica l no d es ( ju g ul o di g astri c ma i nly)

29. F unct i ons The ton g e i s th e mos t im p ortan t articul a tor for speech production . During speech, the ton g u e c a n mak e amazi n g range of movements The p rim a ry fu n ctio n o f t he tongue is to provide a mechanism for taste . T ast e b u d s ar e l o cate d o n d i f feren t area s of th e to n gu e , bu t ar e ge n era l l y fo u n d arou n d th e edg e s . They ar e sensitiv e to fou r m a i n tastes : B i tte r , S o ur , S a lt y & Swe e t

30. The t o ng u e i s ne e de d fo r suc k in g , chewin g , swall o win g , eat i n g , drinkin g , kis s i n g , sweep i n g th e mo u t h fo r f o od de b ris an d oth e r particle s an d for makin g fun n y face s (poking th e tongue ou t , wagg l i n g it) T rumpet e rs an d hor n & fl u t e players hav e v er y we l l devel o pe d ton g ue muscles , an d ar e a b l e t o p erfor m r ap i d, control l e d moveme n t s o r articul a ti o ns

31. Clinical Notes ⦿ Lacerati o n s o f t h e tongue ⦿ T on g u e - T i e ( ankylog l ossi a ) (due to larg e frenu l um) ⦿ Les i o n o f t h e hypo g l o s s a l nerve The protrud e d tongu e devia t es towar d th e sid e o f th e lesi o n T on g u e i s atro p h i e d & wrinkled

32. i r s o o n s s n yo r ri, i w ll o io yo r ion

33. P al a te ⦿ L i e s i n th e roof o f th e oral cavity ⦿ Has tw o part s : Hard ( bon y ) pa l ate anteriorly S o f t ( muscula r ) pal a te posteriorly ha r d soft palate

34. Hard Palate ⦿ Li e s i n th e roof o f th e ora l cavity ⦿ Forms th e fl o o r o f t h e nasa l cavity ⦿ Formed by: P a l a ti n e processe s o f m a xil l ae i n front Horizontal pl a te s o f pala t ine bone s be h i n d B o un d e d b y alveo l a r arches

35. Hard Palate ⦿ P o steriorl y , cont i nu o u s with soft palate ⦿ Its undersurface covered by mucoperiosteum ⦿ S h ow s trans v ers e ridges i n the ant e rior parts

36. Soft Palate ⦿ At t ache d t o th e posterio r b o rder of th e har d pa l ate ⦿ Covered o n it s upp e r an d low e r surface s b y muco u s me m brane ⦿ Comp o se d of: Muscl e fi b ers A n ap o ne u rosis L ympho i d tissue Glands B l oo d ves s els Nerves

37. Palatine Aponeurosis ⦿ Fibro u s shea t h ⦿ At t ache d t o posterio r borde r of har d p al a te ⦿ I s expa n de d te n do n o f te n so r vel l i palatini ⦿ S p l i t s t o e nclos e mus c ulu s uvulae ⦿ Give s orig i n & insertio n t o p al a ti n e muscles

38. Mus c les ⦿ T enso r vel i palatini Origin: spine of sphenoid; auditory tube Insertion : form s palatin e ap o neu r osis Action: T ense s sof t palate Leva t o r vel i palatini Origin: petrous temporal bone, auditory tube, palatin e ap o neu r osis In s ertion : palatin e aponeurosis Action: Raises sof t palate Musculu s uvulae Origi n : pos t erio r borde r o f har d palate Insertion : mucos a o f uvula Action: Elevates uvula

39. Mus c les Palatoglossus O r ig i n : pa l at i n e ap o ne u rosis Insert i on : sid e o f t on g ue Acti o n : pu l l s root o f ton g ue upward , narrowing orop h arynge a l isth m us Palatopharyngeus O r ig i n : pa l at i n e ap o ne u rosis Insertio n : posterio r b o rder of thyroi d cartil a ge Acti o n : E l evates wall o f the pharynx

40. Sensory Nerve Supply Mostl y b y th e maxi l lar y nerve thro u g h it s branch e s: G r eat e r pal a ti n e nerve Lesse r p a l a ti n e nerve Nasopa l at i n e nerve Glossopharyngea l nerve supp l i e s th e reg i o n o f th e s oft palate

41. Motor Nerve Supply A l l th e muscles , excep t tenso r vel i pa l at i n i , are suppl i e d b y the: Pharyngeal pl e xus T enso r vel i pa l at i n i suppl i e d b y the: Nerve to medial pterygoid, a branch of the mandibu l a r divisio n o f th e trige m in a l nerve

42. Blood Supply Branches o f th e maxi l lar y artery Greate r p a l at i ne Lesse r pala t ine Sphenopalatine Ascendi n g pa l at i ne , branc h o f the faci a l artery Ascen d i n g ph a r y ng e a l , branc h o f the externa l ca r ot i d a r tery

43. Clinical Notes Cl e f t pa l at e : Unilateral Bilateral Median P a ralysis o f th e sof t palate The ph a r y ng e a l isth m u s ca n n ot b e c lose d durin g swall o wing and speech P har y nge a l isthmus