Muscles surrounding Complete Denture

As we know that the muscles play an important role in stability and support of a prosthesis,hence we should be well learned about their peripheries and actions.

1. GOOD MORNING

2. PRESENTED BY : NABID ANJUM MDS 1 ST YEAR DEPARTMENT OF PROSTHODONTICS MUSCLES SURROUNDING PERIPHERY OF COMPLETE DENTURE

3. Myolo gy – study of muscles . Muscle is a soft tissue made up of a large number of fibres bound together by connective tissue into bundles,or fascicles. These bundles are surrounded by connective tissue sheaths and grouped together into still larger bundles. The whole muscle is enveloped by a connective tissue sheath,the epimysium . Muscles can be voluntary(skeletal) or involuntary (smooth or cardiac)

4. INTRODUCTION: Musculature is involved directly in several important phases of complete dentures. They exert a direct influence upon the peripheral extensions,shape and thickness of denture bases,position of teeth both horizontally and vertically and facial appearances. In addition they are active during mastication,speech and deglutition. The muscles that are intimately involved with prosthodontics are skeletal muscles.

5. In the majority of skeletal muscles ,the origins and insertions are in bone. However,many skeletal muscles involved in complete denture construction have a bony origin but insert into an aponeurosis,a raphe,or another muscle. Following group of muscles are studied in relation to complete dentures : Muscles of mastication and its accessory muscles . Muscles of facial expression. Muscles of soft palate. Muscles of tongue.

6. MUSCLES OF MASTICATION

7. Process of grinding and chewing food into smaller pieces in the oral cavity ,turning it into a food bolus MASSETER TEMPORALIS MEDIAL PTERYGOID LATERAL PTERYGOID They enable the lower jaw to make closing,opening , protrusive,retrusive movements along with side to side movements . INNERVATED BY : MANDIBULAR BRANCH OF TRIGEMINAL NERVE DEVELOPMENT: 1 ST BRANCHIAL ARCH

8. QUADRILATERAL 3 layers- Superficial,Middle and Deep. Superficial layer- Largest. Origin- anterior 2/3rd of lower border of zygomatic arch. Insertion- lower part of lateral surface of ramus. Middle layer Origin- anterior 2/3rd of deep surface and posterior 1/3rd of lower border of zygomatic arch. Insertion- middle part of ramus. Deep layer Origin-deep surface of zygomatic arch Insertion- upper part of ramus and coronoid process MASSETER:

9. ACTION - Elevates the mandible to close the mouth INNERVATION - Masseteric nerve, branch of anterior division of mandibular nerve.

10. CLINICAL IMPLICATIONS: ON DENTURE BORDER: In this area ,the buccal flange must converge medially to avoid displacment due to contraction of masseter muscle,because the muscle fibres in that area are vertical and oblique. An active masseter muscle will create concavity in the outline of distobuccal border. A less active masseter may result in convex border.

11. MASSETERIC NOTCH: Instruct the patient to open mouth wide and then close against the resting force of your finger. Instructing the patient to close against the finger on tray handle causes masseter muscle to contract and push against the medially situated buccinator muscle.

12. PALPATION : The patient is asked to clench their teeth and using both hands,the practioner palpates the masseter muscles on both sides extraorally,making sure that the patient continues to clench during the procedure. Palpating the origin of the masseter bilaterally along the zygomatic arch and continue to palpate down the body of mandible where the masseter is attached .

13. FAN SHAPED ORIGIN- temporal fossa and temporal fascia INSERTION- coronoid process and anterior border of ramus. INNERVATION- Deep temporal branch, branch of anterior division of mandibular nerve TEMPORALIS:

14. ACTION - Elevates the mandible Helps in protruding Helps in side to side grinding movements. CLINICAL IMPLICATIONS:

15. PALPATION: Pateint is asked to clench the teeth. The anterior region above the zygomatic arch and anterior to TMJ. The middle region above TMJ and superior to zygomatic arch. The posterior region above and behind the ear.

16. Quadrilateral Small superficial and large deep head ORIGIN: Superficial head-maxillary tuberosity. Deep head-medial surface of lateral pterygoid plate. INSERTION -Medial surface of angle and ramus of mandible, as high as the mandibular foramen. . MEDIAL PTERYGOID:

17. ACTION- Elevates the mandible Helps protruding the mandible. Right medial pterygoid and left lateral pterygoid helps turn chin to the left side . INNERVATION - Nerve to medial pterygoid ,branch of main trunk of mandibular nerve

18. CLINICAL IMPLICATIONS: Most commonly involved muscle in MYOFACIAL PAIN DYSFUNCTION SYNDROME. Trismus following inferior alveolar nerve block is mainly due to involvement of medial pterygoid muscle.

19. PALPATION: Functional manipulation is done when the muscles becomes fatigued and symptomatic. The muscle contracts as the teeth are coming in contact .

20. Short and conical Has upper and lower head Upper head: Origin - infratemporal fossa and crest of greater wing of sphenoid Insertion - pterygoid fovea on the anterior surface of neck of mandible Lower head: Origin -lateral surface of lateral pterygoid plate Insertion - articular disc in TMJ LATERAL PTERYGOID:

21. ACTION - Depresses the mandible to open the mouth Helps protrude the mandible (along with medialpterygoid ) Left lateral pterygoid and right medial pterygoid turn the chin to the left side. It is the only muscle that helps in abduction of the jaw. INNERVATION -branch from anterior division of mandibular nerve

22. CLINICAL IMPLICATIONS: Most commonly involved muscle is MYOFACIAL PAIN DYSFUNCTION SYNDROME UNILATERAL FAILURE OF LP : deviation of mandible towards the affected side on opening. BILATERAL FAILURE OF LP : Limited opening,loss of protrusion.

23. PALPATION SUPERIOR HEAD : equal pressure on lateral poles of condyle as patient opens and closes his mouth. INFERIOR HEAD : placing the forefinger ,over the buccal area of the maxillary third molar region and slide in medial direction behind the maxillary tuberosity .

24. ACCESSORY MUSCLES OF MASTICATION DIGASTRIC MYLOHYOID GENIOHYOID INFRAHYOID

25. DIGASTRIC ORIGIN INSERTION ANTERIOR BELLY DIGASTRIC FOSSA TENDON ATTACHED TO THE BODY POSTERIOR BELLY MASTOID NOTCH GRETER CORNUA OF HYOID BONE ACTION Depresses mandible while opening mouth Elevates hyoid bone while swallowing

26. MYLOHYOID ORIGIN INSERTION MYLOHYOID LINE OF MANDIBLE POSTERIOR FIBRES TO THE HYOID BONE. MIDDLE & ANTERIOR FIBRES DECUSSATE TO FORM FIBROUS BANDS ACTION Depresses mandible while opening mouth Elevates hyoid bone and floor of mouth during deglutition

27. GENIOHYOID ORIGIN INSERTION Inferior genial tubercle of mandible Anterior surface of hyoid bone ACTION Elevates hyoid bone. Depresses mandible while opening mouth .

28. INFRAHYOID STERNOHYOID Depresses hyoid bone STERNOTHYROID Depresses larynx THYROHYOID Depresses hyoid bone Elevates larynx OMOHYOID Depresses hyoid bone and larynx

29. MUSCLES OF FACIAL EXPRESSION The muscles in this region convey the emotional state of an individual by controlling expressions of the face. These muscles move the skin , create lines and folds and cause movement of facial features. Also called mimetic muscles.

30. Frontalis Procerus Corrugator supercilli Depressor supercilli Orbicularis oculi Nasalis Orbicularis oris Zygomaticus major Zygomaticus minor Levator anguli oris The facial muscles include : Depressor anguli oris Levator labii superioris Depressor labii inferioris Risorius Buccinator Mentalis Platysma

31. Forms the occipito-frontalis muscle along with the occipitalis muscle ORIGIN- G alea aponeurotica INSERTION- into the orbicularis oculi muscle and skin of forehead INNERVATION- facial nerve BLOOD SUPPLY- supratrochlear and supraorbital arteries ACTION -lift the eyebrows(surprise) Also acts when a view is too distant or dim FRONTALIS

32. Only muscle capable in closing eyes 3 parts- orbital ,palpebral ,lacrimal Orbital part-around the orbital margin Origin - medial part of medial palpebral ligament Insertion -forms concentric rings and blends with frontalis Action – closes eyes tightly Palpebral part-in eyelids Origin -lateral part of medial palpebral ligament Insertion -lateral palpebral raphae Action -closes eyes gently- sleep or blinking ORBICULARIS OCULI

33. Lacrimal part-lateral and deep to lacrimal sac Origin - lacrimal fascia and lacrimal bone Insertion - upper and lower eyelids Action – dilates the lacrimal sac Antagonist muscle- levator palpebrae superioris INNERVATION - temporal and zygomatic branch of facial nerve BLOOD SUPPLY - opthalmic , angular and zygomatico -orbital arteries

34. Originate from maxilla and mandible in midline forms an ellipse around the mouth 2parts-extrinsic and intrinsic Intrinsic part- Origin - The superior incisivus and inferior incisivus Insertion - Angle of the mouth Extrinsic part- Origin -Formed by converging muscles ( buccinator and elevator and depressors of lips) Insertion – Lips and angle of the mouth ORBICULARIS ORIS

35. ACTION - Kissing muscle Closes and puckers lips P urses the mouth INNERVATION - Buccal branch of facial nerve BLOOD SUPPLY- Superior and inferior labial artery

36. PROSTHODONTIC CONSIDERATIONS: Because of horizontal direction of fibres of orbicularis oris,it has indirect effect on impression and denture base. Main muscle of lip. Its tone depends on the support it gets from buccal flange and position of the teeth . Frenum contains fibres of orbicularis oris and mentalis muscle,hence the denture should be carefully fitted around it to maintain a seal without causing soreness.

37. FROWNING MUSCLE Small pyramidal shaped muscle Located in the medial end of the eyebrows ORIGIN -medial end of supercilliary arch INSERTION -skin of medial half of eyebrow ACTION -draws eyebrows medially downwards,producing vertical wrinkles INNERVATION -temporal branch of facial nerve BLOOD SUPPLY- opthalmic artery CORRUGATOR SUPERCILLI

38. ORIGIN- from nasal bone and upper part of nasal cartilage INSERTION- skin between eyebrows ACTION - Helps in frowning, bring the fibres along the medial angle of eyebrows. Contributes to expression of anger. INNERVATION- T emporal, lower zygomatic and buccal branch of facial nerve BLOOD SUPPLY- F acial artery PROCERUS

39. ORIGIN - Anterior part of zygomatic bone INSERTION - Skin at the corner of the mouth( modiolus ) ACTION - draws angle of mouth upward and laterally. Responsible for smiling. INNERVATION - B uccal and zygomatic branch of facial nerve. BLOOD SUPPLY –Facial artery ZYGOMATICUS MAJOR

40. ZYGOMATICUS MINOR ORIGIN - Malar bone INSERTION - Upper lip medial to corner of mouth ACTION - Draws the lip upward, backward and outward (sad facial expressions) INNERVATION - B uccal branch of facial nerve BLOOD SUPPLY- F acial artery

41. LEVATOR LABII SUPERIORIS Quadratus labii superioris . ORIGIN - Medial half of infraorbital margin of maxilla. INSERTION -Skin of lateral half of upper lip. ACTION -Elevates the upper lip retracts or evert the lower lip(pouting or sadness). INNERVATION- Z ygomatic branch of facial nerve. BLOOD SUPPLY- F acial artery.

42. Also called caninus . ORIGIN - Canine fossa immediately below infraorbital foramen INSERTION - Skin at the corner of the mouth forming modiolus . ACTION - Elevates corners of mouth during expressions such as smile INNERVATION - B uccal branch of facial nerve BLOOD SUPPLY- F acial artery LEVATOR ANGULI ORIS It attaches beneath the frenum and affects the position of frenum .

43. Associated with frowning. ORIGIN - oblique line of mandible in relation to canine and premolars INSERTION - skin at the corner of the mouth, blending with orbicularis oris muscle ACTION - draws corner of the mouth down and laterally INNERVATION - mandibular branch of facial nerve BLOOD SUPPLY- facial artery DEPRESSOR ANGULI ORIS

44. Quadratus labii inferioris ORIGIN -Oblique line of mandible INSERTION -Skin of lower lip ACTION- D epresses the lower lip draws the lip downward and laterally INNERVATION - Mandibular branch of facial nerve BLOOD SUPPLY- F acial artery DEPRESSOR LABII INFERIORIS

45. BUCCINATOR Primary muscle of cheek 3 fibres-upper ,middle and lower Upper fibres Origin - maxilla , opposite to molar teeth Insertion - upper lip Middle fibres Origin - Pterygomandibular raphae . Insertion- Decussate before passing onto the lips. Lower fibres Origin -mandible opposite to molar teeth Insertion-lower lip Lower fibres . Origin -mandible opposite to molar teeth Insertion -lower lip

46. Pterygomandibular raphae separate buccinator and superior constrictor muscle ACTION -Whistling action Aids in mastication Aids in neonates to suckle INNERVATION - B uccal branch of facial nerve BLOOD SUPPLY - Buccal artery

47. PROSTHODONTIC CONSIDERATIONS : The buccinator muscle provides support and mobility for the soft tissues of the cheek. A major function of this muscle is to keep the cheeks taunt.If this were not so,when the jaws close,the cheeks would collapse and be caught between the teeth. Another very important function is its participation in deglutition . It is important to know that the proper external or polished surface is obtained by functional influence of buccinator to provide stability to the denture bases . The polished surface occupies a position of equilibrium among these group of muscles and is referred as NEUTRAL ZONE .

48. Overlaps sternocleidomastoid. ORIGIN - Upper part of pectoral and deltoid fascia INSERTION - Anterior fibres-Base of mandible Poterior fibres-Skin of lower face and lip ACTION -Depresses mandible Pulls the angle of the mouth downwards Draws the skin of neck superiorly during clenching INNERVATON - Cervical branch BLOOD SUPPLY- S uprascapular and S ubmental arteries PLATYSMA

49. Chiasma of facial muscles. Location- lateral and slightly superior to angle of mouth (10-12mm lateral to the angle of the mouth) Comprises of- Orbicularis oris Buccinator Levator anguli oris Depressor anguli oris Zygomaticus major Levator labii superioris Risorius Platysma MODIOLUS

50. PROSTHODONTIC CONSIDERATIONS: Activity of modiolus muscle is a guide for occlusal plane determination. Muscles radiate from the modiolus like an array of fans. The modiolus is lateral to lower premolars so it will displace a lower denture if those teeth are set too far buccally . With teeth loss, the modiolus displaced and give appearance of sunken cheeks.

51. MENTALIS Pouting muscle Paired central muscle of the lower lip ORIGIN -Incisive fossa of mandible INSERTION -Skin of the chin ACTION- raises central portion of lips In conjunction with orbicularis oris , it allows the lips to pout. Mentalis contraction causes wrinkles in the chin ; eg - doubt INNERVATION -Mandibular branch of facial nerve

52. The mentalis muscle attachment to the alveolar ridge can dictate the level of extension of the labial flange of the mandibular denture below the crest of the ridge. PROSTHODONTIC CONSIDERATIONS : The contraction of this muscle is capable of dislodging a mandibular denture,particularly when the ridge in the anterior region is the same height as the formix of the vestibule .

53. RISORIUS ORIGIN - fascia of parotid gland INSERTION -Skin at the corner of the mouth ; modiolus ACTION -Retracts angle of mouth to produce a smirk INNERVATION - Buccal branch BLOOD SUPPLY- Facial artery

54. FACIAL NERVE Motor nerve supply Emerges from the parotid gland and gives 5 branches- 1. Temporal -frontalis,auricularis,orbicularis oculi 2. Zygomatic -orbicularis oculi 3. Buccal - cheek and upper lip 4. Marginal mandibular – lower lip 5. Cervical - platysma

55. Damage to the facial nerve results in paralysis of the muscles of facial expression on one side of the face Infranuclear lesions- Bell’s palsy Whole of the face on the same side -gets paralysed Supranuclear lesions -Lower part of the opposite side of the face is affected CLINICAL SIGNIFICANCE

56. MUSCLES OF SOFT PALATE The soft palate(velum) is a mobile muscular flap . It hangs down from the posterior border of the hard palate into the pharyngeal cavity like a curtain . It separates the nasopharynx from oropharynx. The oral surface of soft palate is thicker and lined by non keratinized stratified squamous epithelium .

57. The soft palate consists of five pairs of muscles,i.e : EXTRINSIC MUSCLES: Tensor palati ( tensor veli palatini ) Levator palati ( levator veli palatini ) Palatoglossus Palatopharyngeus INTRINSIC MUSCLE: Musculus uvulae INNERVATION: MOTOR SUPPLY- All muscles of soft palate except tensor Veli palatini are supplied by cranial root of accessory nerve ,whereas tensor veli palatini is supplied by nerve to m edial pterygoid ,a branch of mandibular nerve. SENSORY SUPPLY- Lesser palatine nerves and glossophary n geal nerve.

58. PALATINE APONEUROSIS It is a sheet of fibrous tissue that provides stability and flexibility to the soft palate and serves as an anchoring point for a number of its muscles. Along its attachment to the hard palate,the palatine aponeurosis continues with the periosteum and submucosal connective tissue on the oral and nasal surfaces on the hard palate.

59. TENSOR VELI PALATINI( tensor palati ) Thin,triangular muscle. ORIGIN : Lateral side of auditory tube. Part of the base of skull. INSERTION: It descends,converges to form a delicate tendon,which winds round the pterygoid h amulus,passes through buccinator and flattens to form palatine aponeurosis . ACTIONS: Tightens the soft palate. Opens the suditory tube.

60. LEVATOR VELI PALATINI Cylindrical muscle. ORIGIN: Inferior aspect of auditory tube. Inferior surface of petrous temporal bone. INSERTION: Into the upper surface of palatine aponeurosis . ACTIONS: Elevates soft palate and closes pharyngeal isthmus. Opens auditory tube.

61. PALATOGLOSSUS ORIGIN : Oral surface of palatine aponeurosis . INSERTION: Descends into palatoglossal arch,to the side of the tongue at the junction of its oral and pharyngeal parts. ACTIONS : Pulls up the root of the tongue.

62. PALATOPHARYNGEUS It consists of two fasciculi that are separated by levator veli palatini . ORIGIN : Anterior fasciculi : from posterior border of hard palate. Posterior fasciculi : from palatine aponeurosis . INSERTION: Posterior border of the lamina of the thyroid cartilage. Wall of the pharynx . ACTIONS : Pulls up the wall of pharynx and shortens it during swallowing.

63. PASSAVANT’S RIDGE : Fibres of palatopharyngeus Membrane of pharynx Form a sphincter in Superior constrictor Constitute Passavant’s muscle Contraction o f the muscle r aises a ridge PASSAVANT’S RIDGE Soft palate when elevated comes in Contact with PASSAVANT’S RIDGE Closure of Pharyngeal Isthmus.

64. MUSCULUS UVULAE Longitudinal strip,placed on each side of median plane. ORIGIN : Posterior nasal apine . Palatine aponeurosis . INSERTION: Mucous membrane of uvula. ACTIONS: Pulls up the uvula.

65. PROSTHDONTIC CONSIDERATIONS: CLASSIFICATION OF SOFT PALATE : BY HOUSE Large and normal in form. Shows a movable band of tissue 5mm-12mm distal to a line drawn across the distal edges of tuberosities . CLASS 2 Medium sized and normal in form. Shows a resilient band of 3-5mm distal to a line drawn across the palate distal to tuberosities . CLASS 3 CLASS 1 Usually accompanies a small maxilla. The curtain of soft tissue turns abruptly 3-5mm anterior to a line drawn across the palate distal to tuberosities .

66. POSTERIOR PALATAL SEAL: The soft tissues along the junction of the hard and soft palates on which pressure within the physiologic limits of the tissues can be applied by a denture to aid in the retention of the denture.- GPT 8 It is the most posterior most limiting structure in maxillary denture. Resist the horizontal and lateral torquing of the maxillary denture and provide the rete tion . Maintains contact of the denture with soft palate during functional movements.

67. PTERYGOMAXILLARY SEAL : Extends through pterygomaxillary notch continuing 3-4mm anterolaterally approximating the mucogingival junction. Occupies the entire width of hamular notch.

68. VIBRATING LINE : The imaginary line across the posterior part of the Palate marking the division between movable and immovable tissues Of soft palate. ANTERIOR VIBRATING LINE: CUPID BOW SHAPED APPEARANCE. ALWAYS ON SOFT PALATAL TISSUES. TO PERFORM VALSALVA MANEUVER ALSO LOCATED BY ASKING THE PATIENT TO SAY ‘AH’ WITH SHORT VIGOROUS BURSTS. POSTERIOR VIBRATING LINE: MARKS THE DEMARCATION BETWEEN MOVABLE & IMMOVABLE PART OF SOFT PALATE MARKS THE MOST DISTAL EXTENSION OF DENTURE BASE. IMAGINARY LINE AT JUNCTION OF TENSOR VELI PALATINI MUSCLE AND MUSCLES OF SOFT PALATE.

69. TONGUE “ Tongue is barely three inches long but it can kill a person six feet tall ” Tongue is a muscular organ situated in the floor of the mouth. Associated with the functions of taste,speech,mastication and deglutition. Oral part – lies in the mouth. Pharyngeal part – lies in the pharynx . These parts are separated by a V shaped sulcus: Sulcus terminalis

70. DEVELOPMENT OF TONGUE Appears at the end of 4 th week. Connective tissue develops from local mesenchyme. ANTERIOR 2/3RD : From two lingual swellings and one tuberculum impar,which arise from 1st branchial arch Supplied by lingual nerve and chorda tympani POSTERIOR 1/3rd : From the cranial large part of the hypobranchial eminence,from the third arch. Supplied by glossopharyngeal nerve. POSTERIOR MOST: From the fourth arch. Supplied by superior laryngeal nerve .

71. EXTERNAL FEATURES OF TONGUE : A ROOT : Attached to the mandible and soft palate above,and to the hyoid bone below. It is related to geniohyoid and mylohyoid muscle. A TIP OR APEX : Forms the anterior free end. At rest lies behind the upper incisor teeth. A BODY : a curved upper surface or dorsum. an inferior surface. The dorsum is divided into oral and pharyngeal parts. The inferior surface is confined to the oral part only.

72. FUNCTIONS OF TONGUE

73. PAPILLAE OF THE TONGUE : Gives the anterior 2/3 rd of the tongue its characteristics rough appearnce . FILIFORM PAPILLAE: Smallest and most numerous. Located along the entire dorsum of the tongue. G ive rise to velvety appearance of the tongue. FOLIATE PAPILLAE: S mall folds of mucosa located just infront of palatoglossal arch along the lateral surface of the tongue. CIRCUMVALLATE PAPILLAE: Large is size 1-2mm in diameter and 8-12 in number . Arranged in form of V with apex pointing backwards . Each is cylindrical projection surrounded by circular sulcus. FUNGIFORM PAPILLAE: Numerous near tip and margins of tongue. Smaller than vallate papillae. Visible as discret pink or bright red pin heads.

74. WRIGHT’S CLASSIFICATION OF TONGUE POSITION : CLASS I : The tongue lies in the floor of the mouth with the tip forward and slightly below the incisal edges of the mandibular anterior teeth. CLASS II : The tongue is flattened and broadened but the tip is in normal position. CLASS III : The tongue is retracted and depressed into the floor of the mouth ,with the tip curled upward,downward or assimilated into the body of the tongue. CLASS I position is ideal,because in such a case the floor of the mouth is at an adequate height ,hence the lingual flange of the denture contacts it and maintains the peripheral seal of the denture .

75. ARTERIAL SUPPLY OF TONGUE : Tongue is supplied by the lingual artery which is branch of external carotid artery. Root of the tongue is also supplied by tonsillar artery which is a branch of facial artery.

76. A middle fibrous septum divides tongue into right and left halves. Each halves contains Four intrinsic and Four extrinsic muscles. INTRINSIC MUSCLES : SUPERIOR LONGITUDINAL INFERIOR LONGITUDINAL TRANVERSE VERTICAL EXTRINSIC MUSCLES : STYLOGLOSSUS HYOGLOSSUS GENIOGLOSSUS PALATOGLOSSUS MUSCLES OF TONGUE

77. INTRINSIC MUSCLES: Occupy upper part of the tongue. Attached to the submucous fibrous layer and to the median fibrous septum. Alter the shape of the tongue. SUPERIOR LONGITUDINAL- Lies beneath the mucous membrane. Shortens the tongue ,makes its dorsum concave . INFERIOR LONGITUDINAL- Lying close to the inferior surface of the tongue. Between genioglossus and hyoglossus . Shortens the tongue,makes its dorsum convex .

78. TRANSVERSE- Extends from median septum to the margins. Makes the tongue narrow and elongated. VERTICAL- Found at the borders of the anterior part of tongue. Makes the tongue broad and flattened.

79. EXTRINSIC MUSCLES: GENIOGLOSSUS- LIFE SAVING MUSCLE Fan shaped muscle. Forms the bulk of tongue. ORIGIN : Upper genial tubercle of mandible. INSERTION: Upper fibres –tip of the tongue Middle fibres – dorsum Lower fibres – the hyoid bone ACTIONS : Retracts the tongue. Depresses the tongue. Pulls the posterior part of tongue forwards and protude the tongue forwards.

80. HYOGLOSSUS- ORIGIN : Greater cornu ,front of lateral part of body of hyoid bone. INSERTION : Side and inferior aspect of tongue. ACTION : Depresses the tongue. Retracts the protruded tongue.

81. STYLOGLOSSUS: ORIGIN : Tip and part of anterior surface of styloid process. INSERTION : Into the side of tongue. ACTION : Pulls tongue upwards and backwards during swallowing.

82. PALATOGLOSSUS- ORIGIN : Oral surface of palatine aponeurosis . INSERTION : Side of tongue(junction of oral and pharyngeal parts ) ACTION : Pulls up the root of tongue, approximates palatoglossal arches, closes oropharyngeal isthmus.

83. NERVE SUPPLY OF TONGUE :

84. EFFECT OF TONGUE IN COMPLETE DENTURE Role of tongue in impression making in alveolingual sulcus: ANTERIOR PART: Mainly influenced by G enioglossus muscle,lingual frenum and to a lesser extent by sublingual gland. The lingual border of the impression in this region should extend down to make contact with the floor of the mouth,when the tip of the tongue touches the upper lip. MIDDLE PART: When the middle of the lingual flange is made to slope towards the tongue,it can extend below the level of mylohyoid ridge. In this way the tongue rests on the top of the flange and aids in stabilizing the lower denture on residual ridge.

85. POSTERIOR PART: Flange can turn laterally towards the ramus to fill the fossa and complete the typical s shaped lingual flange. Role of tongue size: SMALL : Facilitate impression making but jeopardize the lingual seal. LARGE: Problem in impression making Denture stability Tongue biting. In edentulous patients,without replacement the tongue often remains hypertropied .

86. Role of tongue space: Artifical teeth must be arranged in NEUTRAL ZONE, where , inward pressure of cheeks and lips=outward pressure of tongue If tongue is cramped by denture lateral pressure exerted instability in denture when tongue moves.

87. ANOMALIES OF TONGUE: FISSURED TONGUE MACROGLOSSIA BENIGN MIGRATORY GLOSSITIS TONGUE TIE CLEFT TONGUE LINGUAL VARICES HAIRY TONGUE LINGUAL VARICES

88. CONCLUSION Knowledge of anatomy,physology and functions of the muscles is an essence to understand the complex morphological and functional changes in the muscle with aging or with complete and partial edentulism . The knowledge will help us to reach optimal prosthetic success,as muscles plays significant and perhaps didacting role in affecting stability and retention of prosthesis.

89. REFERENCES BD Chaurasia’s HUMAN ANATOMY for Dental students;2 nd edition. Syllabus of complete denture: Charles M.Heartwell ;4 th edition. Essentials of complete Denture: Sheldon winkler ;3 rd edition . Anatomy of facial expression and its prosthodontic significance Alexander L,MartoneD.D.S.; jpd vol 12,issue 6 nov-dec 1962 THANK YOU