Orofacial musculatue

DR.CHAITHRASHREE

1. ORO-FACIAL MUSCULATURE DR. CHAITHRASHREE.S.RAO IST MDS

2. CONTENTS: Introduction Classification Embryology of muscle Anatomy of muscle Muscles of – Scalp Ear Eyelid Extraocular Nose

3. Mouth Mastication Suprahyoid Infrahyoid Lateral Cervical muscles Lateral Vertebral muscles Tongue Palate Pharynx Triangles of the neck Conclusion

4. INTRODUCTION Muscles are formed from Myoblasts of the Mesenchyme which forms the bulk of the mesoderm . There are more than 600 muscles in our body . Muscle cells can be excited chemically, electrically and mechanically to produce an action potential that is transmitted along their cell membranes. In man, muscle tissue constitutes 40–50% of the body mass. These muscles have their full complement of cells during development and increase in size only by increasing the volume of individual myocytes, rather than by increasing the number of cells.

5. Both striated and smooth muscles arise from Mesoderm with an exception for a few which originate from the Ectoderm . The intrinsic muscles of the trunk are derived from the myotomes while the muscles of head and limbs differentiate directly from the mesoderm. A  myotome  is a group of muscles innervated by the ventral root a single  spinal nerve . This term is based on the combination of two Ancient Greek roots; “ myo -” meaning “muscle”, and “tome”, a “cutting” or “thin segment”. Like spinal nerves, myotomes are organised into segments because they share a common origin

6. During the  third week  of gestation, the notochord has developed and the mesoderm lateral to it has differentiated into three columns . The column running directly next to the notochord is the  paraxial mesoderm . The paraxial mesoderm will then start to divide into cube- shapebilaterally paired segments called  somites . Each of these segments corresponds to a division of the  vertebral column  and spinal cord in an adult . EMBRYOLOGY

7. Each somite will differentiate into three different regions. The ventral portion will form the sclerotome while the dorsal portion forms the  dermomyotome  which later splits into the dermatome and myotome . sclerotome – forms the  ribs  and vertebrae dermatome – forms connective tissue and dermis of the  skin myotome  – forms the skeletal muscle of the  neck , trunk, and limbs

8. MESODERMAL ORIGIN MUSCLES INNERVATION SOMITOMERE 1,2 SUPERIOR, INFERIOR, MEDIAL RECTI; INFERIOR OBLIQUE C-3 SOMITOMERE 3 SUPERIOR OBLIQUE C-4 SOMITOMERE 4 MUSCLES OF MASTICATION C-5 SOMITOMERE 5 LATERAL OCULAR C-6 SOMITOMERE 6 FACIAL MUSCLES C-7 SOMITOMERE 7 STYLOPHARYNGEUS C-9 SOMITES 1,2 LARYNGEAL MUSCLES C-10 SOMITES 1-4 TONGUE C-12 SOMITES 3-7 STERNOMASTOID TRAPEZIUS C-11 CRANIO-FACIAL MUSCLE ORIGINS:

9. General principles of muscle differentiation MYOBLASTS , the precursors of muscle cells develop from mesenchymal cells. They have a prominent nucleus and an enlarged nucleolus, many free ribosomes and polysomes in their cytoplasm, a few uniformly distributed globular mitochondria and sparse endoplasmic reticulum.

10. Structure of muscle fibres:

11. TYPE 1 V/S TYPE 2 MUSCLES TYPE 1 • Small • Slow-firing • Relatively fatigue resistant • Oxidative fibres TYPE 2   • Large • Fast-firing • Fatigable fibres • Type 2a – fast, oxidative, glycolytic fibres • Type 2b – fast, glycolytic, fibres

12. CRANIO-FACIAL MUSCLES :

13. VARIOUS CLASSIFICATION HAVE BEEN SUGGESTED TILL NOW TOPOGRAPHICALLY & FUNCTIONALLY ACC. TO LOCATION ALONE 3. COSMETICALLY

14. ACC. TO LOCATION THESE INCLUDES MUSCLES OF SCALP OR EPICRANIUM EYELID NOSE EAR & MOUTH NECK

15. TOPOGRAPHICALLY & FUNCTIONALLY EPICRANIAL CIRCUMORBITAL AND PALPEBRAL NASAL BUCCOLABIAL

16. COSMETICALLY THEY ARE DIVIDED INTO TWO MAJOR CATEGORIES FACIAL ELEVATORS : levator labii superioris aleque nasi , levator labii superioris , zygomaticus major, levator anguli oris , zygomaticus minor, risorius FACIAL DEPRESSOR : depressor labii inferioris , depressor anguli oris , mentalis

17. OCCIPITOFRONTALIS Origin & Insertion: Has 4 bellies- 2 occipital and 2 frontal which are connected by an aponeurosis ( galea aponeurotica ) Occipital bellies arise from the highest nuchal line and passes forward to attach to the aponeurosis . The 2 muscle bellies are separated in the midline. Frontal belly arises from the aponeurosis and passes forwards to become attached to the upper part of orbicularis oculi and the skin of the eyebrow.

18. NERVE SUPPLY: Facial nerve Post auricular branch to occipitalis Temporal branches to frontalis BLOOD SUPPLY : Branches of the superficial temporal, ophthalmic, posterior auricular and occipital arteries.

19. ACTION: Frontalis: Raise the eyebrows and the skin over the root of the nose, and at the same time draw the scalp forward forming transverse wrinkles of the forehead. Occipitalis : in some individuals occipitalis can pull the scalp backwards, but otherwise it merely anchors the aponeurosis when frontalis elevates the eyebrows.

20. TEMPOROPARIETALIS Variably developed sheet of muscle that lies on either sides of the frontal parts of occipito frontalis and anterior and superior auricular muscles ACTIONS: Elevates the ear. Tightens the scalp.

21. NERVE SUPPLY: Facial nerve Post auricular branch Temporal branches BLOOD SUPPLY : Branches of the superficial temporal, ophthalmic, posterior auricular and occipital arteries.

22. EPICRANIAL APONEUROSIS Fibro muscular sheet that extends from occipital to the eyebrows, Thin and continious over the temporal facia to the zygomatic arch. Ant: splits to enclose the frontal parts Post: btw the occipitalis muscle attached to external occipital protruberance and highest nucal lines On either sides: anterior and superior circular muscles Over the cranial vault: united to skin by fibrous superficial fascia

23. Nerve supply: Occipital part: posterior auricular branch Frontal part: temporal branches of facial nerve Actions: From above: raises eyebrows and skin over the nose as in surprise horror or fright From below: draws scalp forwards , forms transverse wrinkles Occipital part: draws scalp backwards Together moves the scalp backwards and forwards

24. Frontalis muscle is one among the many muscles examined to check the functioning of facial nerve. Transverse wrinkles on the forehead are absent when the patient is asked to look upwards without moving his head in cases of infranuclear lesions of the facial nerves APPLIED ASPECTS

25. Lacerations of the Scalp : The scalp has a profuse blood supply to nourish the hair follicles. Even a small laceration of the scalp can cause severe blood loss. It is often difficult to stop the bleeding of a scalp wound because the arterial walls are attached to fibrous septa in the subcutaneous tissue and are unable to contract or retract to allow blood clotting to take place. Local pressure applied to the scalp is the only satisfactory method of stopping the bleeding

26. Sebaceous gland cysts : The skin of the scalp possesses numerous sebaceous glands, the ducts of which are prone to infection and damage by combs. For this reason, sebaceous cysts of the scalp are common . Scalp Infections: Infections of the scalp tend to remain localized and are usually painful because of the abundant fibrous tissue in the subcutaneous layer. Occasionally, an infection of the scalp spreads by the emissary veins, which are valveless , to the skull bones, causing osteomyelitis. Infected blood in the diploic veins may travel by the emissary veins farther into the venous sinuses and produce venous sinus thrombosis.

27. Black Eye The blood and fluid gathering in the layer of loose areolar tissue following a strike on head tracks freely under the scalp creates generalized swelling over the dome of the  skull . This cannot enter either occipital or temple regions due to the bony attachments of the occipitofrontalis . The blood and fluid track forwards into the  eyelids   as occipitofrontalis has no bony connection anteriorly. This result in creation of hematoma few hours after a head injury or cranial surgery causing black discoloration of skin around the eyes, a condition named black eye.

28. MUSCLES OF THE FACE Also known as muscles of facial expression are subcutaneous muscles. These muscles are regulators (sphincter or dilators) of the three opening on the face namely; the palpebral fissures, nostrils and oral fissure. Facial expressions produced are secondary functions of these muscles. Some anatomists think that facial expressions are merely side effects of the action of the muscles of face.

29. FUNCTIONAL GROUP OF FACIAL MUSCLES :

30. MUSCLES OF EYELID Levator palpebrae superioris Corrugator supercilli Orbicularis oculi

31. ORBICULARIS OCULI Origin and Insertion: From nasal part of the frontal bone and from the frontal process of the maxilla in front of the lacrimal groove. the muscle has three parts:- the palpebral portion, the orbital portion and the lacrimal portion.

32. Palpebral portion: Thin and pale muscle which arises from the bifurcation of the medial palpebral ligament Forms a series of concentric curves and gets inserted into the lateral palpebral raphe.   Orbital portion: Reddish colour form complete ellipse without interruption at the lateral palpebral commisure . The upper portion of the muscle blends with Frontalis and Corrugator   Lacrimal portion: Situated behind the medial palpebral ligament and lacrimal sac. Divides into two; upper and lower parts which are inserted into the superior and inferior tarsi medial to puncta lacrimalia .

33. CORRUGATOR SUPERCILI Origin and Insertion: Arises from medial end of the super- cilliary arch and its fibres pass upwards and lateral between the palpebral and orbital portions of the Orbicularis oculi. Inserted into deep surface of skin, above the middle of the orbital arch .

34. LEVATOR PALAPEBRAE SUPERIORIS Origin: Arises from the under surface of the small wing of the sphenoid anterosuperior to the optic foramen. The narrow tendinous muscle becomes broad and fleshy and end in the wide aponeurosis which splits into three lamellae. Insertion : Superficial lamella: blends with the orbital septum and inserts into the anterior surface of the superior tarsus . Middle lamellae: inserted into the upper margin of the superior tarsus. Deep lamellae: blends with the sheath of rectus superior and attached to the superior fornix of the conjunctiva.

35. NERVE SUPPLY: Both Orbicularis oculi and Corrugator supercilli are supplied by the facial nerve. BLOOD SUPPLY: ORBICULARIS OCULI: Branches of the facial, superficial temporal, maxillary and ophthalmic arteries CORRUGATOR: Branches from adjacent arteries, mainly from the superficial temporal and ophthalmic arteries.

36. FUNCTIONS: Orbicularis oculi: It acts a sphincter muscle. Palpebral portion is involuntary - closes the lid during sleeping/blinking. Orbital portion is voluntary – firm closure of the eyelids. During closure the medial palpebral ligament is tightened and the wall of the lacrimal sac is drawn lateral and forwards forming a vacuum and tears are sucked through the lacrimal canals.

37. ACTIONS: Levator palpebrae superioris – direct antagonist of orbicularis oculi. It raises the upper eyelid and exposes the bulb of the eye. Corrugator supercilli - D raws the eyebrow downwards and medially producing vertical wrinkles of the forehead. Drags the eye brows medially and downward and protects eye from bright sunlight.

38. APPLIED ASPECTS Paralysis from of orbicularis oculi prevents eye from being closed and exposes cornea leaving it to become dry. Lower eyelid falls away from the eyeball forming a pond in which the tears pool and spill over the face. It also causes conjunctival sac to get accumulated with grit causing infections.

39. EXTRA-OCCULAR MUSCLES: Rectus superior Rectus inferior Rectus medialis Rectus lateralis Obliquus superior Obliquus inferior

40. RECTI MUSCLES: Origin and insertion: Arises from a fibrous ring (common annular tendon or tendinous ring) which surrounds the upper, medial, and lower margins of the optic foramen and encircles the optic nerve. It also encloses the lower and medial part of the superior orbital fissure. Two specialised parts of the fibrous ring : A lower, LIGAMENT/TENDON OF ZINN: gives origin to inferior rectus and lower head of lateral rectus. An upper, SUPERIOR TENDON OF LOCKWOOD: gives origin to superior rectus, medial rectus and upper head of lateral rectus. Each muscle passes forward and is inserted into the sclera by a tendinous expansion.

41. SUPERIOR OBLIQUE MUSCLES: Origin and insertion: Arises: above the margin of the optic foramen, above and medial to the origin of superior rectus. The fibres become a rounded tendon and pass through fibrocartilaginous ring or pulley attached to the trochlear fovea of frontal bone . The tendon passes backwards laterally and downwards below the superior rectus Insertion: sclera of the lateral part of the bulb of the eye between insertions of superior rectus and lateral rectus.

42. INFERIOR OBLIQUE MUSCLE: Origin and insertion: Arises from the orbital surface of the maxilla , lateral to the lacrimal groove. The fibres pass laterally backward and upwards between inferior rectus and the floor of the orbit Insertion: sclera of the lateral part of the eye between superior rectus and lateral rectus behind the insertion of superior oblique

43. NERVE SUPPLY : Lateral Rectus: abducent nerve (VI) Superior Oblique: trochlear nerve (IV) Rest of the muscles: occulomotor nerve (III) BLOOD SUPPLY : All extraocular muscles are supplied by Ophthalmic artery.

44. ACTIONS Two extraocular muscles , the medial rectus  and  lateral rectus , work together to control horizontal eye movements Contraction of the medial rectus pulls the eye towards the nose ( adduction  or medial movement).  Contraction of the lateral rectus pulls the eye away from the nose (abduction or lateral movement).  Contraction of the superior rectus produces eye elevation and contraction of superior oblique produces eye depression.   Inferior rectus produces eye depression and Inferior oblique  produces eye elevation

45. Strabismus: or the squint eye A squint is a condition where the eyes do not look together in the same direction. Whilst one eye looks straight ahead, the other eye turns to point inwards, outwards, upwards or downwards. Squints are common and affect about 1 in 20 children. By the direction of the squinting (turning) eye: An eye that turns inwards is called an esotropia . An eye that turns outwards is called an exotropia . An eye that turns upwards is called a hypertropia . An eye that turns downwards is called a hypotropia

46. Congenital squints Congenital squint means that the child is born with a squint, or it develops within the first six months of life. Cause: In most cases, the eye muscles are not balanced but the reason for this is not known. In most cases one eye turns inward. This is called congenital esotropia (sometimes called infantile esotropia ).

47. Paralysis to the Orbital Muscles If the  facial nerve  becomes damaged, the orbital muscles will cease to function. As they are  the only muscles that can close the eyelids, this has some serious clinical consequences. The eye cannot shut  – this can cause the cornea to dry out. This is known as  exposure keratitis . The lower eyelid droops, called  ectropion .   Lacrimal fluid pools in the lower eyelid, and cannot be spread across the surface of the eye. This can result in a failure to remove debris, and ulceration of the corneal surface. The test for facial nerve palsy involves raising the eyebrows and closing the eyelids

48. MUSCLES OF NOSE: DEPRESSOR SEPTI PROCERUS NASALIS DILATOR NARIS POSTERIOR DILATOR NARIS ANTERIOR LEVATOR LABII SUPERIORIS ALAEQUAE NASI

49. ORIGIN AND INSERTION: Procerus ( pyramidalis nasi ): fascia covering the lower part of the nasal bone and upper part of the lateral nasal cartilage . inserted into the skin over the lower part of the forehead between two eyebrows. Its fibres decussate with that of frontalis.

50. Nasalis : Two parts: T ransverse and alar. Transverse part : from maxilla, superior and lateral to incisive fossa. Fibres expand into a thin aponeurosis which is continuous on the bridge of the nose . Alar part is attached by one end to the greater alar cartilage , and by the other to the integument at the point of the nose .

51. The Depressor septi (Depressor aloe nasi ) A rises from the incisive fossa of the maxilla Inserted into the septum and back part of the ala of the nose . It lies between the mucous membrane and muscular structure of the lip . The Dilatator naris posterior: Is placed partly beneath the Quadratus labii superioris . arises from the margin of the nasal notch of the maxilla , and from the lesser alar cartilages . Inserted into the skin near the margin of the nostril. The Dilatator naris anterior : Is a delicate fasciculus, passing from the greater alar cartilage to the integument near the margin of the nostril.

52. Levator labii superioris alaequae nasi : Arises from the upper part of the frontal process of the maxilla and divides into medial and lateral slips. Insertion: Medial slip blends into the perichondrium of the lateral crus of the major alar cartilage of the nose and the skin over it. Lateral slip is prolonged into the lateral part of the upper lip , where it blends with levator labii superioris and orbicuris oris .

53. Nerve supply Facial nerve Blood supply Procerus is supplied mainly by branches from the facial artery Nasalis is supplied by branches from the facial artery and from the infraorbital branch of the maxillary artery Depressor septi is supplied by the superior labial branch of the facial artery Levator labii superioris alaequae nasi is supplied by the facial artery and the infraorbital branch of the maxillary artery

54. A CTIONS: Procerus: draws down the medial angle of the eyebrows and produces transverse wrinkles over the bridge of the nose. The two Dilators (Anterior and Posterior ): E nlarges the aperture of the nares. resist the collapse of the nostrils due to atmospheric pressure. strongly contract during the expression of some emotions such as Anger.

55. Depressor septi : A ntagonist to other muscles of nose. Draws the ala of nose downwards and constricts the nares. Nasalis: D epresses the cartilaginous part of the nose D raws the ala towards the septum.

56. MUSCLES OF THE MOUTH Buccinator Orbicuaris oris Risorius Platysma Levator labii superioris Caninus Zygomaticus Mentalis Levator labii inferioris Triangularis

57. LEAVATOR LABII SUPERIORIS Origin and Insertion Has three heads Angular head Intermediate head/infraorbital head Zygomatic head Angular head : arises from the frontal process of the maxilla passes obliquely downwards and splits into two; one inserts into the greater alar cartilage the other into the lateral part of the upper lip , blending with infraorbital head and orbicularis oris .

58. Intermediate head/infraorbital head: Arises from the lower margin of the orbit above the infra- orbital foramen . Inserted into the muscular substance of the upper lip between the angular head and the Caninus . Zygomatic head: Arises from the malar surface of the zygomatic bone behind the zygomaticomaxillary suture Inserts into medial aspect of the upper lip.

59. CANINUS/ LEVATOR ANGULI ORIS: Origin and insertion Arises from the the canine fossa immediately below the infraorbital foramen Inserted into the angle of the mouth intermingling with those of the Zygomaticus, Triangularis and Orbicularis oris .

60. ZYGOMATICUS MAJOR Origin and insertion: It arises from the anterior aspect of lateral surface of zygomatic bone Inserts into the upper lip medial to the angle of the mouth . Origin and insertion: Arises from the zygomatic bone, in front of the zygomaticotemporal suture . Inserted into the angle of the mouth , where it blends with the fibres of the Caninus , Orbicularis oris and Triangularis . ZYGOMATICUS MINOR

61. NERVE SUPPLY: facial nerve. BLOOD SUPPLY : Levator labii superioris is supplied by the facial artery and the infraorbital branch of the maxillary artery. Caninus is supplied by the superior labial branch of the facial artery and the infraorbital branch of the maxillary artery. Zygomaticus is supplied by the superior labial branch of the facial artery.

62. ACTIONS: Levator labii superioris : elevator of upper lip. Angular head: dilator of naris . Infraorbital and zygomatic head assist in forming the nasolabial furrow. When the whole muscle contracts it gives the expression of contempt and disdain Caninus : helps in producing the nasolabial furrow. Zygomaticus: helps in smiling. Zygomaticus major: pulls the angle of the mouth upwards and lateral Zygomaticus minor: elevates the upper lip

63. DEPRESSOR LABII INFERIORIS Origin and insertion : Arises from the oblique line of mandible, between symphysis and mental foramen. Inserts into the integument of the lower lip . Its fibres blend with that of orbicularis oris and with those from the opposite side.

64. MENTALIS ORIGIN AND INSERTION : Arises from the incisive fossa of the mandible Inserts into the integument of the chin . ORIGIN AND INSERTION : Arises from the oblique line of the mandible. Inserts into the angle of the mouth. At the origin its fibres are continuous with platysma and at the insertion it is continuous with that of orbicularis oris . TRIANGULARIS/ DEPRESSOR ANGULI ORIS

65. NERVE SUPPLY: Facial nerve BLOOD SUPPLY: Mentalis is supplied by the inferior labial branch of the facial artery and the mental branch of the maxillary artery. Depressor labii inferioris is supplied by the inferior labial branch of the facial artery and the mental branch of the maxillary artery. Triangularis : supplied by the inferior labial branch of the facial artery and the mental branch of the maxillary artery

66. ACTIONS: MENTALIS: Raises and protrudes the lower lip and at the same time wrinkles the skin of the chin, expressing doubt or disdain. DEPRESSOR LABII INFERIORIS: draws the lower lip downwards and laterally, as in expression of Irony TRIANGULARIS: depresses angle of mouth medially along with Platysma

67. BUCCINATOR ORIGIN AND INSERTION : Arises from the outer surface of the alveolar process of the maxilla and mandible, corresponding to the molars anteriorly and from the anterior border of pterygomandibular raphe posteriorly. Insertion: the fibres converge towards the angle of the mouth. The central fibres intersect with each other, those from below continuous with upper segment of Orbicularis oris and those from above with the lower segment.

68. ORBICULARIS ORIS ORIGIN AND INSERTION It arises from Anterior surface of maxilla Anterior surface of mandible Modiolus Insertion : Into the skin and mucous membrane of lips. Occupies the entire width of lips No direct attachment to the skeleton Fibers are divided in the upper & lower gp . That can cross each other at acute angle lateral to corner of mouth

69. Previously considered as a sphincter muscle but recent studies have shown that the muscle consists of 4 independent quadrants (viz. upper, lower, left and right) Each quadrant contains large Pars peripheralis and small Pars marginalis . Both peripheralis and marginalis originate from the modiolus . Pars peripheralis decussate at the midline and insert into the contralateral philtrum edge where as pars marginalis is a continuous band from modiolus to modiolus

70. NON-SYNDROMIC CLEFT LIPS: Non syndromic cleft lip is a complex genetic disorder with variable phenotype, largely attributed to interactions of environment and multiple genes. A cleft is non syndromic if there is only single malformations. The severity of CL, varies from minimal to complete bilateral CL. Minimal CL, includes superficial scarring, notching of upper lip, notching of alveolar ridge and asymmetry in alar cartilages . Various literature supports that non syndromic cleft lips are caused due to orbicularis oris sub-epithelial defects. In cases of cleft lip the pars peripheralis runs all the way the columella while the pars marginalis end at the margin of the defect

71. RISORIUS ORIGIN AND INSERTION Arises in the fascia over Masseter and passes horizontally forward above the platysma. Insertion: into the skin of the angle of the mouth.

72. Nerve supply: Facial nerve Blood supply: Orbicularis oris : supplied mainly by the superior and inferior labial branches of the facial artery, the mental and infraorbital branches of the maxillary artery and the transverse facial branch of the superficial temporal artery Buccinator is supplied by branches from the facial artery and the buccal branch of the maxillary artery. Risorius is supplied mainly by the superior labial branch of the facial artery

73. ACTIONS: Orbicularis oris : Pursing of lips and pouting. Buccinator : compresses the cheeks so that during mastication the food is kept under immediate pressure of the teeth. whistling Risorius : retracts the angle of the mouth and helps in producing unpleasant grinning expression

74. PLATYSMA Origin and insertion Origin: upper parts of pectoral and deltoid fasciae and fibres run upwards and medially Insertion: Anterior fibres to the base of the mandible Posterior fibres to the skin of the lower face and lip and maybe continuous with the Risorius

75. Nerve supply: Facial nerve Blood supply: By the submental branch of the facial artery and by the suprascapular artery Actions: Releases pressure of skin on the subjacent veins Depresses mandible Pulls the angle of the mouth downwards as in horror or surprise

76. MODIOLOUS It is defined as a lateral point to the corner of the angle of the mouth where the muscles of facial expression converge. The muscles which form the modiolus are: Orbicularis oris Buccinators Caninus Triangularis Zygomaticus major Risorius Platysma Levator labii superioris

77. A few of the common facial expressions and the muscles producing them: EXPRESSION MUSCLES RESPONSIBLE SMILING AND LAUGHING ZYGOMATICUS MAJOR SADNESS LEVATOR LABII SUPERIORIS GRIEF DEPRESSOR ANGULI ORIS ANGER DILATOR NARIS AND DEPRESSOR SEPTI FROWNING CORRUGATOR SUPERCILLI AND PROCERUS HORROR PLATYSMA SURPRISE FRONTALIS DOUBT MENTALIS GRINNING RISORIUS CONTEMPT ZYGOMATICUS MINOR CLOSING THE MOUTH ORBICULARIS ORIS WHISTLING BUCCINATOR

78. DEVELOPMENT OF EMOTIONAL EXPRESSIONS IN INFANTS : EXPRESSIONS AGE SURPRISE 5 MONTHS SMILING 6-8 WEEKS ENJOYMENT 16-18 WEEKS LAUGH 7 MONTHS CRY BIRTH DISGUST 4 MONTHS ANGER 3-4 MONTHS SAD 6MONTHS FEAR 7-11 MONTHS Margaret Wolan Sullivan, PhD; Michael Lewis, PhD, Emotional Expressions of Young Infants and Children. Infants and Young Children:Vol . 16, No. 2, pp. 120–142

79. The development of spontaneous facial responses to others’ emotions in infancy: An EMG study Jakob Kaiser ,  Maria Magdalena Crespo- Llado ,  Chiara Turati  &  Elena Geangu Viewing facial expressions often evokes facial responses in the observer. In the current study, 4- and 7-month old infants were presented with facial expressions of happiness, anger, and fear. Electromyography (EMG) was used to measure activation in muscles relevant for forming these expressions: zygomaticus major (smiling), corrugator supercilii (frowning), and frontalis (forehead raising). The results indicated no selective activation of the facial muscles for the expressions in 4-month-old infants. For 7-month-old infants, evidence for selective facial reactions was found especially for happy (leading to increased zygomaticus major activation) and fearful faces (leading to increased frontalis activation), while angry faces did not show a clear differential response. Such mechanisms seem to undergo important developments at least until the second half of the first year of life.

80. CLINICALLY, THE FACIAL NERVE IS EXAMINED BY TESTING THE FOLLOWING FACIAL MUSCLE: FRONTALIS Ask the patient to look upwards without moving his head, and look for the normal wrinkles of forehead. CORRUGATOR SUPERCILLI: Frowning and making vertical wrinkles of the forehead. ORBICULARI OCULI: Tight closure of the eyes. ORBICULARIS ORIS: Whistling and pursing the teeth. BUCCINATOR: Puffing the mouth and then blowing as in whistling DILATORS OF TEETH: Showing the teeth.

81. BELL’S PALSY Definition : The bell’s palsy is definied as a facial paralysis of acute onset attributed to a acute non- supportive inflammation of facial nerve within stylomastoid foramen . It may occur at any age from infancy to old age, but appears to be most common in young adults; males are affected more than female. 

82. Causes: 1-Trauma : Basal skull fractures, Facial injuries, Penetrating injury to middle ear, Altitude paralysis. (barotrauma), Scuba diving & Lightning . 2-Infection: External otitis, Otitis media & Mastoiditis,, etc ) 3-Metabolic : Diabetes mellitus & Hypertension. 4-Neoplastic : Seventh nerve tumor & Benign lesions of parotid. 5-Idiopathic : Familial Bell palsy, Autoimmune syndrome & Multiple sclerosis.

83. clinical features: 1-Pain behind ear (mastoid foramen). 2- affection of taste and hearing. 3-Inability to raise eye brow. 4-Inability to close eye on affected side. 5-Flattening of nosolabial fold. 6-Accumulation of food inside the cheek(affected side). 7-Dropping corner of mouth. 8-Dripping of saliva.

84. Assessment Tests for bell's palsy include the following: Muscle test : 1. Forehead wrinkling (frontalis muscle) 2 . Eye closure (orbicularis oculi muscle) 3 . Wide smile 4 . Whistling 5 . Blowing ( eg , buccinator muscle, orbicularis oris muscle, zygomatic muscle).

85. TETANUS Tetanus is a clinical diagnosis characterized by a triad of muscle rigidity, muscle spasms and autonomic instability. Clostridium tetani spores enter into the body through any abrasions on the skin. Release tetanospasmin (potent neurotoxin)

86. C/F: Early symptoms of tetanus include  neck stiffness, sore throat dysphagia trismus . Spasm extending to the facial muscles causes the typical facial expression, ‘ risus sardonicus ’. Truncal spasm causes opisthotonus .

87. MOBIUS SYNDROME : It is an extremely rare congenital neurological disorder Characterized by facial paralysis and the inability to move the eyes from side to side. Born with complete facial paralysis and cannot close their eyes or form facial expressions. Limb and chest wall abnormalities sometimes occur with the syndrome.

88. MELKERSONS-ROSENTHAL SYNDROME : It is a rare neurological characterized by recurring facial paralysis, swelling of the face and lips (usually the upper lip), and the development of folds and furrows

89. Ramsay Hunt Syndrome: Ramsay Hunt Syndrome: Peripheral facial nerve palsy May be unilateral or bilateral Vesicular rash on ear Ear pain, tingling, tearing, loss of sensation and nystagmus. Ramsay Hunt Syndrome Type II : Reactivation of latent Herpes zoster virus within the dorsal root ganglion of facial nerve is associated with vesicles affecting ear canal

90. Effects of a myofunctional appliance on orofacial muscle activity and structures Antje Tallgren , LDS, Odont Dr; Richard L. Christiansen, DDS, MSD,PhD ; Major M. Ash Jr., DDS, MS , The aim of the study was to examine the effect of an oral shield treatment on orofacial muscle activity and facial morphology in children with lip and/or tongue dysfunction. The sample consisted of 7 girls and 2 boys, 7 to 1 2 years old. EMG recordings with and without the shield in situ were obtained when the shield was placed, and 3, 6, and 12 months later. Lateral cephalograms were obtained at the initial and 1 -year stages. The lip muscles showed dominant activity when the subjects were sucking on an empty straw and during swallowing; this was strongest during the first 3 months. The mentalis, buccinator , and digastric muscles generally showed weaker activity. The anterior temporal muscle showed dominant activity during maximal clench, but after the 3-month stage a significant decrease was noted. After 1 year of treatment, no significant changes in overjet or overbite were observed. Most of the craniofacial growth changes were normal for the age group. The results indicate that treatment with an oral shield caused a decrease in orofacial muscle activity during oral functions .

91. MUSCLES OF THE EAR: AURICULARIS SUPERIOR AURICULARIS ANTERIOR AURIULARIS POSTERIOR

92. ANTERIOR AURICULARIS Smallest & weak muscle Protector of outer ear Origin From aponeuratic tendon of scalp in the temporal region Course & insertion Runs horizontally & backwards & insert into cartilage of outer ear at the ant. Border Nerve supply Temporal branch Action Draws the ear upwards & forwards

93. AURICULARIS S UPERIORIS Largest Just behind the anterior Origin Above the ear from aponeuratic tendon of scalp Course & insertion Descends & converge & insert to medial surface of cartilage Nerve supply Both temporal & post auricular branch Action Elevate the ear

94. AURICULARIS POSTERIORIS Small but strong muscle Retractor of the ear Origin From the base of mastoid process of temporal bone & lateral part of sup. Nuchal line Course & insertion Run horizontally over the insertion of sternocledomastoid muscle to insert on the convexity of cranial surface of conche Nerve supply Post auricular of facial nerve Actions Draw the ear backwards

95. MUSCLES OF THE TONGUE: The tongue muscles are developed from occipital myotome , which is formed by the fusion of four pre-cervical somites . The myotome migrates forward to invade the tongue along the epi-pericardial ridge, carrying its own nerve supply. Development of tongue muscles:

96. MUSCLES OF THE TONGUE – Middle fibrous septum divides the tongue into right and left halves . Intrinsic muscles Superior longitudinal Inferior longitudinal Transverse Vertical Extrinsic muscles Genioglossus Hyoglossus Styloglossus Palatoglossus

97. INTRINSIC MUSCLES - Occupy the upper part of the tongue – Are attached to the submucous fibrous layer and to the median fibrous septum. They alter the shape of the tongue Superior longitudinal muscle – Lies beneath the mucous membrane. It shortens the tongue and makes its dorsum concave Inferior longitudinal muscle – Is a narrow band lying close to the inferior surface of the tongue between the styloglossus and the hyoglossus It shortens the tongue and makes the dorsum convex.

98. Transverse / horizontal muscle – Extends from the median septum to the margins. It makes the tongue narrow and elongated. Vertical muscle – Is found at the borders of the anterior part of the tongue. It makes the tongue broad and flattened.

99. EXTRINSIC MUSCLES - Connect the tongue to the : Mandible via genioglossus Hyoid bone through hyoglossus Styloid process via styloglossus Palate via palatoglossus

100. GENIOGLOSSUS - Fan shaped muscle Which forms the main bulk of the tongue It arises from the upper genial tubercle of the mandible From here the fibers fan out and run backwards Upper fibers are inserted into the tip Middle fibers are inserted into dorsum Lower fibers into hyoid bone. ACTIONS : Upper fibers - retract the tip Middle fibers - depress the tongue Lower fibers - pull the posterior part of the tongue forwards and thus protrude the tongue from the mouth.

101. HYOGLOSSUS Is an important landmark in the submandibular region Origin whole length of greater cornua and lateral part of body of hyoid bone. Fibers run upwards and forwards Insertion side of tongue between styloglossus and inferior longitudinal muscle of tongue Nerve supply hypoglossal nerve Action – depresses tongue, makes dorsum convex and retracts the protruded tongue.

102. STYLOGLOSSUS Origin – tip and adjacent part of the anterior surface of the styloid process as well as from the upper end of the stylohyoid ligament. Fibers – pass downwards and forwards Insertion into the si d e of the tongue, intermingling with the fibers of the hyoglossus Nerve supply – hypoglossal nerve Action – during swallowing it pulls the tongue upwards and backwards.

103. PALATOGLOSSUS - Origin – oral surface of palatine aponeurosis Fibers – descends in the palatoglossal arch Insertion- Side of the tongue (at the junction of oral and pharyngeal parts) Nerve supply – cervical part of accessory nerve Action – pulls up the root of the tongue, approximates the palatoglossal arches and thus closes the oropharyngeal isthmus

104. ARTERIAL SUPPLY – Chiefly derived from lingual artery Root of the tongue is also supplied by the tonsillar and ascending pharyngeal arteries . VENOUS DRAINAGE – The deep lingual vein is the largest and the principal vein of the tongue. It is visible on the inferior surface of the tongue. It runs backwards and crosses the genioglossus and the hyoglossus below the hypoglossal nerve. LYMPHATIC DRAINAGE – Tip of the tongue drains bilaterally to the submental nodes Right and left halves of the remaining part of the anterior 2/3rd of the tongue drains unilaterally to the submandibular nodes. Posterior 1/3rd of the tongue drains bilaterally to the jugulo-omohyoid nodes.

105. APPLIED ANATOMY: Orofacial Myofunctional Disorders ( OMD): With OMD, the tongue moves forward in an exaggerated way during speech and/or swallowing . The tongue may lie too far forward during rest or may protrude between the upper and lower teeth during speech and swallowing, and at rest. signs or symptoms Although a "tongue thrust" swallow is normal in infancy, it usually decreases and disappears as a child grows. If the tongue thrust continues, a child may look, speak, and swallow differently than other children of the same age. Older children may become self-conscious about their appearance.

106. Effect of OMD on speech? Some children produce sounds incorrectly as a result of OMD. OMD most often causes sounds like /s/,/z/, " sh ", " zh ", " ch " and "j" to sound differently. For example, the child may say "thumb" instead of "some“ Both pedodontists and orthodontists may be involved when constant, continued tongue pressure against the teeth interferes with normal tooth eruption and alignment of the teeth and jaws Physicians predict the presence of a blocked airway (e.g., from enlarged tonsils or adenoids or from allergies) that may cause forward tongue posture.

107. TREATMENT A speech-language pathologist (SLP) with experience and training in the treatment of OMD will evaluate and treat. Treatment techniques to help both speech and swallowing problems caused by OMD may include the following: increasing awareness of mouth and facial muscles increasing awareness of mouth and tongue postures improving muscle strength and coordination improving speech sound productions

108. Orofacial myofunctional therapy or rest posture therapy We need to teach the muscle where to  rest  again when normal posture is altered. Teeth are moved by light, constant pressure, not by intermittent heavy forces Only treating the intermittent heavy force created by tongue thrusting is not treating the source of the problem. If the tongue is resting low and forward against the teeth and lips are parted for the other 23.5 hours, then we have not addressed the actual problem. The light, constant pressure of the tongue and lips have much more influence on oral equilibrium.