ANATOMY AND PHYSIOLOGY OF EAR, NOSE, THROAT and NEWER INVESTIGATION MODALITIES by DR. AKSHAY B K

A conceptual and picture oriented presentation of basics of ent, anat, physio and some techniques of their functional assessment. Much usefull for undergraduate understanding.

1. ANATOMY AND PHYSIOLOGY OF EAR,NOSE&THROAT. ASSESMENT OF HEARING IN CHILDREN - Dr.AKSHAY.B.K .

2. ANATOMY OF EAR

3. THE EXTERNAL EAR 1.AURICLE OR PINNA It is made of single piece of yellow elastic cartilage covered with skin except lobule.There is no cartilage between the tragus and crus of the helix and is called incisura terminalis(used for endaural approach). Cartilage and perichondrium from tragus and fat frm lobule is used for reconstructive procedures of middle ear. Cocnhal cartilage is used for correction of depressed nasal bridge.

4. 2. EXTERNAL AUDITORY CANAL Extends fom bottom of concha to tympanic membrane(24mm). Outer part is directed upward backwards and medially while its inner part is directed downwards forwards and medially. A)CARTILAGINOUS PART it forms outer one third(8mm) of the canal.cartilage is continuation of outer framework of pinna. It has two deficiencies (fissures of Santorini). Skin covering the canal is thick and contains ceruminous and pilosebaceous glands which secrete wax. Hair is present in the outer one third of the canal. B) BONY PART It forms inner two thirds(16mm). Skin lining the canal is thin and continuous with tympanic membrane. 6mm lateral to TM presents a narrowin called ‘ISTHMUS’.(FB) Anteroinferior part presents a deficiency called ‘foramen of huschke ’ upto age of 4 permitting inections to and from parotid.

5. TYMPANIC MEMBRANE It forms the partition between exernal acoustic canal and middle ear. It is obliquely set, posterosuperior part is more lateral than its anteroinferior part. 9-10 mm tall ,8-9mm wide and 0.1 mm thick. It is divided into two parts: 1)PARS TENSA Forms most of tm. Periphery thickened to form a fibrocartilaginous ring ( ANNULUS TYMPANICUS). Central part is tented inwards at the level of tip of malleus(UMBO). ‘Cone of light’ present in the anteroinferior part. 2)PARS FLACCIDA(SHRAPNELLS MEMBRANE) Situated above the lateral process of malleus It is not so tense, appears slightly pinkish.

6. NERVE SUPPLY OF THE EXTERNAL EAR PINNA Greater auricular nerve(C2,3) Lesser occipital nerve (C2) Auriculaotemporal nerve( V3) Auricular branch of vagus (CNX) ARNOLDS NERVE. EXTERNAL AUDITORY CANAL Antr wall and roof:auriculotemporal nerve. Postr wall and floor: auricular branch of vagus TYMPANIC MEMBRANE: Antr half of lateral surface:auriculotemporal nerve Postr half of lateral surface:auricular branch of vagus Medial surface:tympanic branch of CN IX ( jacobsons nerve)

7. Middle ear together with Eustachian tube, aditus and antrum is called MIDDLE EAR CLEFT. DIVIDED INTO 3 REGIONS; 1)EPITYMPANUM OR ATTIC.( ABOVE PARS TENSA) 2)MESOTYMPANUM.(OPP TO PARS TENSA) 3)HYPOTYMPANUM.(BELOW PARS TENSA)

8. MASTOID ANTRUM Large air containing space in the upper part of of mastoid. It communicates with the attic through the aditus . Roof:tegmen antri Lateral wall:bone 1.5cms thick ( macevens triangle). MASTOID AND ITS AIR CELL SYSTEM It consists of bone cortex filled with a “honeycomb” of air cells underneath. Classified into three variants: 1)WELL PNEUMATIZED OR CELLULAR: cells are well developed and intervening septa are thin. 2)DIPLOETIC: consists of marrow spaces and few air cells. 3)SCLEROTIC OR ACELLULAR: there areno cells or marrow spaces.

9. OSSICLES OF MIDDLE EAR: they conduct sound energy from TM to the oval window and then to inner ear fluids 1.MALLEUS:It has head, neck, handle(manubrium), lateral,antr process. 2.INCUS:it has a body,long process and a short process. 3.STAPES:it has a head,neck,anterior and posterior crura and a footplate. INTRATYMPANIC MUSCLES: 1)Tensor tympani:attaches to the TM and tenses the TM.(V3) 2)Stapedius: attaches to the neck of stapes and helps to dampen very loud sound preventing noise trauma to inner ear.(CN VII)

10. BLOOD SUPPLY OF MIDDLE EAR: Anterior tympanic branch of maxillary artery ,supplies TM. Stylomastoid branch of posterior auricular artery,supplies middle ear &mastoid air cells. Four minor vessels: Petrosal branch of middle meningeal artery. Superior tympanic branch of middle meningeal artery. Branch of artery of pterygoid canal. Tympanic branch of internal carotid artery. LYMPHATIC DRAINAGE Middle ear-retropharyngeal and parotid nodes Eustachian tube –retropharyngeal group.

11. It is an important organ of hearing and balance. Consists of 2 components; 1)Bony labyrinth 2)Membranous labyrinth. Membranous labyrinth is filled by a clear fluid”ENDOLYMPH ”. Space between bony and membranous labyrinth is filled by “PERILYMPH”.

12. BONY LABYRINTH: consists of 3 parts 1)VESTIBULE : it is the central chamber of labyrinth.in its lateral wall lies “oval window”.medial wall presents two recesses, ‘SPHERICAL RECESS’-lodges the utricle. ‘ELLIPTICAL RECESS’-lodges the saccule.posterosuperior part has five openings of semicircular canal . 2)SEMICIRCULAR CANALS: three in no. lateral ,posterior and superior which lie at rightangles to each other and open into vestibule . 3) COCHLEA :It is a coiled tube making 2.5 -2.75 turns round a central pyramid of bone called ‘ modiolus ’. Base pf modiolus transmits vessels and nerves to the cochlea . It has 3 compartments: Scala vestibuli : Scala tympani. Scala media

13. MEMBRANOUS LABYRINTH: 1)COCHLEAR DUCT(membranous cochlea): it is a blind coiled tube. On cross section it has 3 walls formed by: Basilar membrane which supports organ of cortil Reissners membrane which separtes it from scala vestibuli . Stria vascularis which secretes endolymph. 2)UTRICLE AND SACCULE: it lies in postr part of bony vestibule & receives openings of SCC. Saccule lies anterior to utricle. Both have “macula”, concerned with linear acceleration & deceleration. 3)SEMICIRCULAR CANALS: three in no. they open into utricle, the ampullated end contains neuroepithelium (crista ampullaris ). 4)ENDOLYMPHATIC DUCT AND SAC: Formed due to union of two ducts, one each from saccule and utricle. its terminal part is dilated to form ‘endolymphatic sac’which lies b/n two layers of dura on the postr surface of petrous bone.

14. Blood supply of labyrinth: It is mainly through ‘internal auditory artery or labyrinthine artery’ , a branch of anterior inferior cerebellar artery. INNER EAR FLUIDS : 1)PERILYMPH: resembles CSF ,it fills space between bony and membranous labyrinth.it communicates through CSF via aqueduct of cochlea. Formation(2views): a)filtrate of blood serum secreted by blood capillaries. b)Direct continuation of CSF. 2)ENDOLYMPH: resembles intracellular fluid, fills membranous labyrinth. Secreted by the secretory cells of stria vascularis of cochlea. 1. 2.

15. ORGAN OF CORTI PHYSIOLOGY OF H EARING: ORGAN OF CORTI: THE SENSE ORGAN OF HEARING Situated on the basilar membrane 1)HAIR CELLS: receptors of hearing, transduce sound energy to electrical energy. Richly supplied with afferent cochlear fibres. 2)TECTORIAL MEMBRANE : It overlies organ of corti , shearing force between tectorial membrane and hair cells produce stimulus to hair cells. 3)SUPPORTING CELLS.

16. INNER EAR SOUND SIGNAL(environment) PINNA EXTERNAL AUDITORY CANAL TYMPANIC MEMBRANE OSSICLES STAPES FOOT PLATE MECHANISM OF HEARING : 1)CONDUCTION OF SOUND

17. Movements of stapes footplate transmitted to cochlear fluids movement of basilar membrane shearing force between tectorial membrane and the hair cells distortion of hair cells trigger nerve impulse auditory nerve AUDITORY CORTEX(area 41 ). 2)TRANSDUCTION OF MECHANICAL ENERGY TO ELECTRICAL IMPULSES: TRAVELLNG WAVE THEORY: A sound wave ,depending on its frequency,reaches a maximum amplitudeon a particular place on the basilar membrane and stimulates that segment . Higher frequency sounds are represented in the basalturn of cochlea and lower ones towards the the apex.

18. ANATOMY OF NOSE NOSE is pyramidal in shape with its root up and base directed downwards. Nasal pyramid consists of osteocartilaginous framework covered by muscles and skin. Mainly studied under three headings: THE EXTERNAL NOSE. THE INTERNAL NOSE. THE PARANASAL SINUSES.

19. THE EXTERNAL NOSE: OSTEOCARTILAGINOUS FRAMEWORK: upper 1/3 rd is bony while lowen2/3rds are cartilaginous, BONY PART: consists of two nasal bones meeting in midline,resting on nasal process of frontal bones & held between frontal processes of maxillae. CARTILAGINOUS PART : consists of Upper lateral cartilages: extend from undersurface of nasal above to the alar cartilages below,fuse with each other & with upper border of septal cartilage in midline. Lower free edge is seen intranasally as ‘nasal valve’. Lower lateral cartilages(alar): each alar cartilage is U shaped. It has a lateral crus which forms ala amd a medial crus which runs in the columella . Lesser alar cartilages(sesamoid): two or more in no. Lie above and lateral to alar cartilages. They are connected with oneanother & with adjoining bones by perichondrium & periosteum. Septal cartilage: It runs under the nasal bones to nasal tip. Supports the dorsum of cartilaginous part of nose.

20. These bring about the movements of nasl tip, ala & overlying skin. PROCERUS NASALIS LEVATOR LABII SUPERIORIS ALAEQUE NASI DEPRESSOR SEPTI ANTR AND POSTR DIALATOR NARES

21. 2)THE INTERNAL NOSE It is divided into 2 cavities by nasal septum. Nasal cavity communicates with exterior through nostrils & with nasopharynx through ‘ choana ’ . Skin lined portion-the vestibule . Mucosa lined portion-the nasal cavity proper. VESTIBULE OF NOSE: It is the anterior and inferior skin lined portion of nasal cavity. It contains sebaceous glands,hair follicles and hair caleed ‘ vibissae ’. A) nasal valve : Boundaries: Laterally by lower border of upper lateral cartilage& antr end of inferior turbinate Medially by cartilaginous part of septum. Caudally by floor of pyriform aperture. B)nasal valve area: It is the cross sectional area forming the boundaries of the valve. It is least cross sectional area of nose which regulates airflow and resistance on inspiration. vestibule

22. NASAL CAVITY PROPER Each nasal cavity has a lateral wall,medial wall,roof and a floor. ROOF: Antr sloping part by nasal bones. Postr part by sphenoid phone. Middle horizontal part by cribriform plate. FLOOR: Anterior 3/4 th by palatine process of maxilla. Posterior 1/4 th by horizontal part of palatine bone. LATERAL NASAL WALL: Three occasionally, four turbinates mark the lateral wall. Turbinates are scroll like bony projections covered by a mucous membrane. LATERAL WALL OF NOSE

23. MIDDLE TURBINATE: It is a part of ethmoid bone. It is attached to lateral wall by a bony lamella (basal lamella). Its attachment is in an S shaped manner. Ostia of various sinuses draining antr to basal lamella form antr group of PNS& those opening postr to it for postr group of PNS. MIDDLE MEATUS lies below middle turbinate. Uncinate process :hook like structure running from anterosuperior to posteroinferior direction. Anteroinferior border is attached to lateral wall Posteroinferior end is attached to inferior turbinate. Bulla ethmoidalis : it is an ethmoidal cell situated behind the uncinated process. Bulla may be a pneumatized cell or a solid bony prominence. The space between uncinate process and bulla ethmoidalis is called HIATUS SEMILUNARIS. Various sinuses opening in middle meatus: A)maxillary sinus, frontal sinus,middle ethmoidal sinuses.

24. SUPERIROR TURBINATE: It is also a part of ethmoid bone. Situated postr and supr to middle turbinate. Important landmark to identify ostium of sphenoid sinus. SUPERIOR MEATUS: It is a space below supr turbinate. Postr ethmoid cells (1-5)open into it. SPHENOETHMOIDAL RECESS : It is situated above the supr turbinate, sphenoid sinus opens into it. INFERIROR TURBINATE : a separate bone, below it lies the inferior meatus where NLD opens.

25. MEDIAL WALL OF NOSE: FORMED BY NASAL SEPTUM Septum consists of 3 parts: 1)COLUMELLAR SEPTUM: formed by fusion of medial crura of both the alar cartilages. 2)MEMBRANOUS SEPTUM: Consists of double layer f skin with no bony or cartilaginous support. It lies b/n columella & caudal border of septal cartilage. 3) SEPTUM PROPER: Consists of osteocartilaginous framework with mucous membrane. Its principal components are: A)PERPENDICULAR PLATE OF ETHMOID. B)THE VOMER. C)QUADRILATERAL CARTILAGE Minor contributions from crest of nasl bones,nasal spine of frotal bone,rostrum of sphenoid,anteriror nasal spine of maxilla,crests of maxilla and palatine bone

26. PARANASAL SINUSES: These are air containing cavities in certain bones of skull. They have been divided into two groups: 1)ANTERIOR GROUP: includes maxillary, frontal & anterior ethmoidal sinuses. Their ostia lie anterior to basal lamella. 2)POSTERIOR GROUP: Includes posterior ethmoidal sinuses which opens into superior meatus. Sphenoid sinus which opens in sphenoetmoidal recess.

27. BLOOD SUPPLY OF LATERAL WALL OF NOSE

28. LITTLE’S AREA OR KIESSELBACH’S PLEXUS: It’s a vascular area in the anteroinferior part of septum. Anterior ethmoidal, sphenopalatine, greater palatine and septal branch of superior labial arteries & their corresponding veins form anastomosis. Commonest site of epistaxis.

29. NERVE SUPPPLY OF LATERAL NASAL WALL

30. PHYSIOLOGY OF NOSE : Functions pf nose are classified as: 1)RESPIRATION : it is the natural pathway for breathing. It also permits breathing and eating simultaneously. It allows ventilation of the PNS. Nasal cycle: nasal mucosa undergoes rhythmic cyclical congestion and decongestion,thus controlling the airflow. It varies 2-4 hrs. 2)AIRCONDITIONING OF INSPIRED AIR: A)filtration & purification : Vibrissae acts as filters against larger particles. Mucus filters finer particles (0.5-3 µm) like dust ,pollen ,bacteria. B)temperature control of inspired air: It is regulated by the large surface of nasal mucosa, mucous membrane is highly vascular with cavernous spaces & sinusoids which controls the blood flow,thus acts a efficient ‘radiator’. As a result temp of inspired air is brought to that of bodys normal temp. C)humidification: Relative humidity of atmospheric air varies depending on climatic conditions. Nasal mucous membrane adjusts the relative humidity of inspired air to 75% or more.

31. 3) PROTECTION OF LOWER AIRWAY Mucociliary mechanism: nasal mucosa is rich in goblet cells,secretory glands which produceb’mucus blanket’ It consists of superficial mucus layer & deeper serous layer floating on top of cilia which are constantly beating like a conveyer belt towards nasopharynx carrying FB. B) Enzymes & immunoglobulin: Mucus contains “ muramidase ”(lysozyme) which kills bacteria &viruses. Also contains IgE,IgA , inteferons . C)sneezing It is a protective reflex, FB which irritate nasal mucosa are expelled by sneezing. 4)VOCAL RESONANCE: Nose forms a resonating chamber for certain consonants in speech (like M/N/NG) When nose is blocked speech becomes denasal ( i.e M/N/NG are uttered asB /D/G. 5)NASAL REFLEXES: Smell of food causes reflex secretion of saliva & gastric juice. Sneezing reflex. Nasobronchial & nasopulmonary reflexes ( ses pulmonary resistance) NASOPHARYNX

32. 6)OLFACTION: It is important for pleasure & enjoying taste of food,when nose is blocked food tastes bland. Smell is perceived in the olfactory region in nose, situated high up in the nasal cavity. This area contains millions of olfactory receptor cells . Central processes of olfactory nerves passthrough the cribriform plate of ethmoid & ends in mitral cells olfactory bulb. Axons of mitral cells form olfactory tract & carry smell impulses to prepyriform cortex and amygdaloid nucleus where it reaches consciousness.

33. ANATOMY OF THROAT : It is studied under three headings: 1)ANATOMY OF ORAL CAVITY. 2)ANATOMY OF PHARYNX AND PHYSIOLOGY OF DEGLUTITION.. 3)ANATOMY OF LARYNX AND PHSIOLOGY OF PHONATION.

34. ANATOMY OF ORAL CAVITY: LIPS : they form anterior boundary of oral vestibule. BUCCAL MUCOSA: it lines the the inner surface of cheeks and lips, anteriorly it extends to the meeting line of lips. GUMS(GINGIVAE): they surround the teeth & cover upper and lower alveolar ridges. RETROMOLAR TRIGONE: it is a triangular area of mucosa covering anterior surface of the ascending ramus of mandible. HARD PALATE: it forms the roof of the oral cavity. FLOOR OF MOUTH: it is crescent shaped area between the gingivae and undersurface of tongue. Ducts of submandibular salivary glands open here. Parts of oral cavity

35. THE TONGUE: anterior 2/3rds of tongue of are included in the oral cavity. posterior 1/3 rd is situated behind the circumvallate papilla & forms part of oropharynx . Actions of tongue muscles: Inferior Longitudinal: moves tip up & down Superior Longitudinal: moves tip up & down Transverse: narrows & lengthens tongue Vertical: flattens & depresses tongue Genioglossus : Prevents tongue from falling back Styloglossus : Pulls tongue up & back Palatoglossus : Pulls tongue back Hyoglossus : Depresses tongue INTRINSIC MUSCLES OF TONGUE EXTRINSIC MUSCLES OF TONGUE

36. Nerve Supply of Tongue *** except palatoglossus which is supplied by pharyngeal plexus Anterior 2/3 Posterior 1/3 Sensory Lingual N Glosso -pharyngeal N Motor Hypoglossal N *** Taste Chorda tympani Glosso -pharyngeal N

37. Papillae in tongue THESE ARE ELEVATED PROJECTIONS ON THE SURFACE OF TONGUE. Lingual taste buds sit on lateral borders of raised papillae. Papillae in tongue

38. CLASSIFICATION OF PAPILLAE: Fungiform: at tip & sides of tongue Circumvallate: just in front of terminal sulcus Foliate: at posterior lateral margins of tongue Filiform: centre of tongue, have no taste buds. TASTE MAP: Sweet = Sucrose Salty = NaCl Sour = HCl Bitter = Quinine

39. Taste Pathway

40. LYMPHATIC DRAINAGE OF ORAL CAVITY

41. ANATOMY OF PHARYNX Pharynx is a conical fibromuscular tube forming upper part of the air and food passages. It is 12-14cm long extending from base of skull to loer border of cricoid cartilage. Width of pharynx 3.5cm at its base but narrows to 1.5cm at pharyngo- esophageal junction. S TRUCTURE OF PHARYNGEAL WALL:(From within outwards it has 4 layers) 1)MUCOUS MEMBRANE:it is formed by ciliated columnar in the nasopharynx and squamous epithelium elsewhere. 2)PHARYNGOBASILAR FASCIA: it is a fibrous layer which lines the muscular coat. 3)MUSCULAR COAT: it consists of 2 ayers of muscles with 3 muscles in each A)External layer :containing superior, middle & inferior constrictors. B)Internal layer :containing stylopharyngeus,salpingopharyngeus,palatopharyngeus muscles. 4)BUCCOPHARYNGEAL FASCIA: it covers the outer surface of constrictor muscles. LAYERS OF PHARYNX

42. MUSCLES OF PHARYNX

43. K ILLIANS DEHISCENCE: infr constrictor has two parts : thyropharyngeus & cricopharyngeus . The gap between these 2 layers is called killians dehiscence. Common site for herniation of pharyngeal mucosa in cases of pharyngeal pouch. WALDEYERS RING: Scattered throughout the subepithelial layer of pharynx is the lymphoid tissue which is aggregated at places to form masses collectively called waldeyers ring; A)the adenoids. B)palatine tonsils. C)lingual tonsil. D)tubal tonsils. E)lateral pharyngeal bands F)nodules in posterior pharyngeal wall.

44. DIVISIONS OF PHARYNX Anatomically pharynx is divided inti three parts: 1)Nasopharynx. 2)Oropharynx. 3)Hypopharynx or laryngopharynx. Lower Limit of Nasopharynx Lower border of soft palate or Junction b/w hard & soft palate Oropharynx Tip of epiglottis or Body of hyoid bone or Base of vallecula Hypopharynx Lower border of cricoid or Lower border of C6 vertebra

45. NASOPHARYNX : Its the uppermost part of pharynx, extending from the base of skull to the level of the soft palate. ROOF: formed by basisphenoid & basiocciput . POSTERIOR WALL: formed by arch of the atlas vertebra covered by prevertebral muscles & fascia. FLOOR: formed by soft palate anteriorly & deficient posteriorly to form nasopharyngeal isthmus. ANTERIOR WALL: formed by choana separted from each other by nasal septum. LATERAL WALL : each lateral wall presents the pharyngeal opening of Eustachian tube. Above and behind the elevation formed by Eustachian tubal opening, is a recess called FOSSA OF ROSSENMULLER ,which is the commonest site for origin of carcinoma.

46. NASOPHARYNGEAL ISTHMUS: It separates nasopharynx from oropharynx. Bounded anteriorly by soft palate ,posteriorly by mucosal ridge on nasopharyngeal wall called PASSAVANT’S ridge( palatopharyngeus ). Closure of this isthmus prevents nasal regurgitation & nasal intonation. NASOPHARYNGEAL TONSIL: It is a subepithelial collection of lymphoid tissue at the junction of roof and postr wall of nasopharynx. It increases in size upto age of 6 years and then gradually atrophies. EPITHELIAL LINING: Lined by pseudostratifed ciliated columnar epithelium.

47. Functions of nasopharynx Acts as passage for air which has been warmed & humidified in the nose into larynx & trachea. Through Eustachian tube it ventilates the middle ear and equalizes air pressure on both side of TM.This function is important for hearing. Elevation of soft palate against posterior pharyngeal wall helps to cut off nasopharynx from oropharynx. This function is important during swallowing,vomiting,gagging&speech . Acts as a resonating chamber during voice production. Acts as a drainage channel for the mucus secreted by nasal & nasopharyngeal glands. LYMPHATICS: Drain into upper deep cervical nodes either directly or indirectly through retropharyngeal and parapharyngeal lymph nodes.

48. OROPHARYNX It extends from the plane of hard palate above to the plane of hyoid bone below. BOUNDARIES: 1)Posterior wall : it lies opposite to 2 nd & upper part of 3 rd cervical vertebrae. 2)Anterior wall: formed by base of tongue,postr to circumvallate papillae. Lingual tonsils one on either side, situated in the base of tongue. Valleculae:they are cup shaped depressions lying between the base of tongue & anterior surface of epiglottis. 3)Lateral wall: Formed by palatine tonsil. Anterior pillar(palatoglossal arch). Posterior fold( palatopharyngeal arch). LYMPHATICS: They drain into upper jugular chain particularly the jugulodigastric node.

49. Oropharyngeal Isthmus Separates oral cavity from oropharynx Boundaries are: Superior: Junction between hard & soft palate Inferior: Circumvallate papillae Lateral: Anterior tonsillar pillars ( palatoglossus )

50. Functions of oropharynx: As a chamber for passage of food and air. Helps in pharyngeal phase of deglutition. Forms part of vocal tract for certain speech sounds. Helps in appreciation of taste. 5) Provides local defence & immunity against harmful intruders into air and food passages. ( waldeyers ring: they are strategically placed at the portals of air and food entry, pathogens which happen to enter these lymphoid masses are dealt by IgM & IgG antibodies.

51. It is the lowest part of pharynx & lies behind and partly on larynx. Its upper limit is a plane passing from the body of hyoid to posterior pharyngeal wall. Lower limit is the lower border of cricoid cartilage. It lies opposite to 3 rd ,4 th ,5 th ,6 th cervical vertebrae . Subdivided into three regions: 1)PYRIFORM FOSSA. 2)POSTCRICOID AREA 3)POSTERIOR PHARYNGEAL WALL. HYPOPHARYNX OR LARYNGOPHARYNX

52. HYPOPHARYNX OR LARYNGOPHARYNX: 1)PYRIFORM FOSSA: it lies on either side of larynx & extends from pharyngoepiglottic fold to upper end of esophagus . Bounded laterally by thyroid cartilage & thyrohyoid membrane & medially by AEfold , posterolateral surfaces of arytenoid & cricoid cartilages. It forms the lateral chanel of food. 2)POSTCRICOID REGION: It is the part of the anterior wall of laryngopharynx b/n upper & lower borders of cricoid lamina. 3)POSTERIOR PHARYNGEAL WALL: Extends from the level of hyoid bone to the level of cricoarytenoid joint.

53. LYMPHATIC DRAINAGE: Pyriform sinus drains into upper jugular chain. Lymphatic from posterior pharyngeal wall & postcricoid region drain into lateral pharyngeal or parapharyngeal nodes and then to deep cervical lymph nodes. FUNCTIONS OF LARYNGOPHARYNX: It is a common pathway fro food and air. Provides a vocal tract for resonance of certain speech sounds helps in deglutition,ni.e cricopharyngeal sphincter must relax when pharyngeal muscles are contracting.

54. Anatomy of larynx The larynx lies in front of hypopharynx opposite the 3 rd to 6 th cervical vertebrae. The larynx is divided anatomically in to : supra glottis . glottis . And sub glottis . By the falls and true vocal cords.

55. The supraglottis consists of superiorly the epiglottis and aryepiglottic folds as they sweep down to the arytenoids. Its lower border is the ventricular bands ( false cords) which form the upper border of the glottis . The glottis includes the vocal cords and anterior commissure and posterior commissure. The sub glottis becomes the trachea at the lower border of the cricoid .( between true v.c . and lower border of the cricoid ) .

56. The framework of the larynx Consists of : hyoid bone number of cartilages ( thyroid,cricoid,arytenoid,corniculate,cuneiform ) connected by ligaments, membranes and intrinsic and extrinsic muscles to give it stability. Lined with a mucous membrane that is continuous above with the pharynx and below with that of the trachea .

57. Cartilaginous skeleton of larynx 9 different cartilages are present in the larynx . Unpaired cartilages: (thyroid, cricoid , epiglottis) Paired cartilages: ( arytenoid , corniculate ,cuneiform)

58. 1)THYROID CARTILAGE: Shield like. Largest of the laryngeal cartilages. Has two laminae meet in the midline inferiorly. The angle of fusion between the laminae is about 90 degree in men and 120 degrees in women. The fused anterior borders in men form a projection, which can be easily palpated known as Adams apple. The laminae diverge posteriorly. The posterior border of the two laminae are prolonged as two slender processes known as the superior and inferior cornua . 2 )CRICOID CARTILAGE: The only cartilage forming a complete ring. Shaped like a signet ring. Composed of of a deep broad quadrilateral lamina posteriorly and a narrow arch anteriorly. The lamina of the cricoid cartilage has articular facets for arytenoid cartilage . These joints are synovial in nature. The cricoid cartilage also articulates with the thyroid cartilage Anterior view Posterior view

59. 3)EPIGLOTTIS: Leaf shaped yellow elastic cartilage . Projects upwards behind the tongue and the body of the hyoid bone . Its upper part is broad and is directed upwards and backwards. Superior margin is free. The sides of the epiglottis is attached to the arytenoid cartilages by aryepiglottic folds . Attached to body of hyoid bone by hyoepiglottic ligament. Stalk like process called petiole petiole

60. The anterior surface of the epiglottis is free and is covered with the same mucous membrane which is of the of pharynx. Forms a single median glossoepiglottic fold and two lateral glossoepiglottic folds. Between these folds lie a depression known as the vallecula . In neonates and infants the epiglottis is omega shaped. This long, deeply grooved, floppy epiglottis protects the nasotracheal air passage during sucking.

61. 3)ARYTENOID CARTILAGES: They are paired. Each cartilage is pyramidal in shape. It has a base which articulates with cricoid cartilage. A muscular process which gives attachment to intrinsic laryngeal muscles. A vocal process which gives attachment to vocal cord. An apex which supports corniculate cartilage. 4) CORNICULATE CARTILAGES: They are paired. Each articulates with the apex of arytenoid cartilage. 5) CUNEIFORM CARTILAGES: They are rod shaped. Each is situated in the AEfold infront of corniculate cartilage. Corniculate cartilage

62. LARYNGEAL JOINTS: 1)CRICOARYTENOID JOINT: It’s a synovial joint. Formed between the base of arytenoid & cricoid lamina. 2 types of movements occur: A)rotatory; here arytenoid moves around a vertical axis.(abduction & aduuction of vocal cords). B)gliding movements; here one arytenoid glides towards the other.(opening& closing of postr part of glottis) 2)CRICOTHYROID JOINT: It’s a synovial joint. Formed by the inferior cornua of thyroid cartilage with a facet on the cricoid cartilage.

63. LARYNGEAL MEMBRANES EXTRINSIC : when membrane or ligament attaches to the structures outside larynx (hyoid bone,trachea ). INTRINSIC : when membranes join within larynx. EXTRINSIC MEMBRANES & LIGAMENTS: THYROHYOID MEMBRANE: it connects thyroid cartilage to hyoid bone. It is pierced by superior laryngeal vessels & internal laryngeal nerve. CRICOTRACHEAL MEMBRANE: it connects cricoid cartilage to 1 st tracheal ring. HYOEPIGLOTTIC LIGAMENT: it attaches epiglottis to hyoid bone.

64. EXTRINSIC MEMBRANES AND LIGAMENTS: a) CRICOVOCAL MEMBRANE: it is a triangular fibroelastic membrane. Its upper border is free & stretches between middle of thyroid angle to the vocal process of arytenoid forming vocal ligament Lower border attaches to the arch of cricoid cartilage. b)QUADRANGULAR MEMBRANE: It lies deep to AE folds. Stretches between epiglottic & arytenoid cartilages. Its lower border forms vestibular ligament which lies in false cord. C) CRICOTHYROID LIGAMENT:the anterior part of cricothyroid membrane is thickened to form cricothyroid ligament. D)THYROEPIGLOTTIC LIGAMENT:it attaches epiglottis tothyroid cartilage.

65. extrinsic muscles of the larynx connect the laryngeal cartilages to Hyoid bone above and trachea below and maintain the position of the larynx in the neck . Divided Into : Infra hyoid group ( strap muscles ) ( Thyrohyoid , Sternothyroid , Sternohyoid , omohyoid ) . Supra hyoid group ( Mylohyoid , Geniohyoid , Stylohyoid , Digastric , Stylopharyngeus , Palatopharyngeus , Salpingopharyngeus (

66. Fig. show strap muscles of the neck

67. Intrinsic muscles of larynx The intrinsic muscles are all paired and move the cartilages in the larynx and regulate the mechanical properties of the larynx. They control the position and shape of the vocal folds and control the elasticity and viscosity of each layer . 1)ACTING ON VOCAL CORDS: ABDUCTORS: posterior cricoarytenoid . B)ADDUCTORS : Lateral c ricoarytenoid,interarytenoid , thyroarytenoid . C)TENSORS: cricothyroid,vocalis (internal part of thyroarytenoid )

68. B)ACTING ON LARYNGEAL INLET: A)OPENERS: thyroepiglottic (part of thyroarytenoid ). B)CLOSERS: interarytenoid (oblique part),aryepiglottic ( postr oblique part of interarytenoids )

69. Interior of larynx : The laryngeal cavity extends from the level of 3rd cervical vertebra to the lower border of the cricoid cartilage (c6) level. At the level of cricoid cartilage it becomes continuous with that of the trachea.

70. Laryngeal cavity is divided by the presence of vestibular and vocal folds into : : 1)VESTIBULE: Larynx above the vestibular fold is known as superior vestibule. 2)VENTRICLE: The ventricle or sinus of the larynx lies between the vestibular and vocal folds. 3)SUBGLOTTIC SPACE : Below the vocal folds is the subglottic space which extends to the level of the lower border of the cricoid cartilage.

71. False vocal cord ( the ventricular bands): which are formed by the mucous membrane covering the ventricular ligament and the upper part of the external portion of the thyroarytenoid muscle. True vocal cords : 2 pearly white bands extending from the middle of thyroid ANGLE TO THE VOCAL PROCESSES OF ARYTENOIDS. Each vocal ligament is ture upper edge of cricovocal membrane covered by closely bound mucous membrane.The blood supply is poor, hence the pearly white appearance of the vocal cords.

72. Vestibule : Lies between the laryngeal inlet and the edges of the false cords. Bounderies : Posterior surface of epiglottis in front. Interval between the arytenoid cartilages behind. Inner surface of the aryepiglottic folds and upper surfaces of the false cords on each side. GLOTTIS(RIMA GLOTTIDIS): it is an elongated space betwwen vocal cords anteriorly & vocal processes and base of arytenoid posterirorly . Anterior2/3 rd is caleed phonatory glottis concerned with phonation. Posterior 1/3 rd is called respiratory glottides.

73. MUCOUS MEMBRANES OF THE LARYNX: Lines the larynx except over the posterior surface of epiglottis ,true vocal cords & corniculate cartilage. Epithelium is ciliated columnar type except over the vocal cords & upper part of vestibule where it is stratified squamous type. LYMPHATIC DRAINAGE: Supraglottic larynx above vocal cords is drained by upper deep cervical nodes. Infraglottic larynx below the vocal cords is drained to prelaryngeal and pretracheal lymph nodes and then to lower deep cervical nodes. Practically no lymphatics for vocal cord.

74. Blood supply of the larynx : Is derived from the laryngeal branches of the superior thyroid artery . . laryngeal branches of the inferior thyroid artery . the cricothryoid branch of the superior thyroid artery . The superior thyroid artery arises from the external carotid artery, and the inferior thyroid artery arises from the thyrocervical trunk . The veins leaving the larynx accompany the arteries; The superior vessels drain to the internal jugular vein by way of the superior thyroid or facial veins , The inferior vessels drain by way of inferior thyroid vein into the brachiocephalic veins. Some venous drainage also occur through the middle thyroid vein into the internal jugular vein.

75. Nerve supply of the larynx : The larynx is supplied by branches of vagus nerve . Superior laryngeal nerve has two laryngeal branches : Internal branch . Entirely sensory . It pierces the thyrohyoid membrane with the superior laryngeal artery and vien . It supplies the cavity of the larynx as far down the level of the vocal cords . External branch . Travels down on the inferior constrictor muscle of the pharynx . It supplies the cricothyroid muscle and part of the ant. Subglottis .

76. Recurrent laryngeal branch of the vagus nerve (CN X) : It has much longer course on the left side than on the right side . On the lt. side it Turns round the arch of aorta . On the rt. Side it Turns round the subclavian artery. In the neck it lies between the trachea and oesophagus as it approach the larynx . It is divided In to : An antero lateral ( motor branch ) : which supply all the intrinsic muscles Of the larynx except the cricothyroid m. Posteromedial ( sensory branch) : which supplies the cavity of the larynx below the level of vocal cords .

77. Physiology of larynx: 1)PROTECTION OF LOWER AIRWAYS: it protects the lower air passage in three different ways; a) Sphincteric closure of laryngeal opening.( closure of laryngeal inlet,false cords,true cords on swallowing of food). b) Temporary cessation of respiration .(reflex generated by afferent fibres of IX th nerve when food touches posterior pharyngeal wall). c) Cough reflex (important mechanism to dislodge & expe l a foreign particle when it comes in contact with respiratory mucosa). 2)PHONATION: voice is produced by the following mechanism(AERODYNAMIC MYOELASTIC THEORY OF VOICE PRODUCTION) Vocal cords are kept adducted. Infraglottic air pressure is generated by the exhaled air from the lungs. The airforce open the cord & is released as small puffs which vibrate the vocal cords to produce sound. The sound is converted into speech by the modulatory action of lips,tongue,palate,pharynx & teeth, Intensity depends on the air pressure produced by lungs. Pitch depends on the frequency with which vocal cords vibrate.

78. 3)RESPIRATION: Larynx regulates the flow of air into the lungs . Vocal cords abduct during inspiration and adduct during expiration. 4)FIXATION OF CHEST: when larynx is closed,chest wall gets fixed & various thoracic & abdominal muscles can act best. This function is important in digging,pulling,climbing,coughing,vomiting .

79. ASSESMENT OF HEARING IN CHIDREN: SCREENING FOR HEARING: Hearing impairment can have a major impact on a child’s development, and because early identification improves prognosis, screening programs have been widely and strongly advocated. Data from the Colorado newborn screening program suggest that if hearing-impaired infants are identified and treated by age 6 mo , these children should develop the same level of language as their age-matched peers who are not hearing impaired. The recommended hearing screening techniques are either otoacoustic emissions (OAE) testing or auditory brainstem evoked responses (ABRs).

80. IDENTIFICATION OF HEARING IMPAIRMENT: The impact of hearing impairment is greatest on an infant who has yet to develop language ; consequently, identification, diagnosis, description, and treatment should begin as soon as possible . In general, infants with a prenatal or perinatal history that puts them at risk (ALPORT SYNDROME,USHER SYNDROME)or those who have failed a formal hearing screening should be monitor Criteria for Referral for Audiologic Assessment AGE (months) REFERRAL GUIDELINES FOR CHILDREN WITH “SPEECH” DELAY 12 No differentiated babbling or vocal imitation 18 No use of single words 24 Single-word vocabulary of ≤10 words 30 <100 words; no evidence of 2 word combinations; unintelligible 36 <200 words; no use of telegraphic sentences; clarity <50% 48 <600 words; no use of simple sentences; clarity ≤80%

81. Guidelines for Referral of Children with Suspected Hearing Loss AGE ( mo ) NORMAL DEVELOPMENT 0-4 Should startle to loud sounds, quiet to mother’s voice, momentarily cease activity when sound is presented at a conversational level 5-6 Should correctly localize to sound presented in a horizontal plane, begin to imitate sounds in own speech repertoire or at least reciprocally vocalize with an adult 7-12 Should correctly localize to sound presented in any plane Should respond to name, even when spoken quietly 13-15 Should point toward an unexpected sound or to familiar objects or persons when asked 16-18 Should follow simple directions without gestural or other visual cues; can be trained to reach toward an interesting toy at midline when a sound is presented 19-24 Should point to body parts when asked; by 21-24 mo , can be trained to perform play audiometry

82. 0-6 months of age Behavioural observation audiometry (BOA ) unconditioned, reflexive responses to complex (not frequency-specific) test sounds such as noise, speech, or music presented using calibrated signals from a loudspeaker or uncalibrated noisemakers. Does not give indication of threshold. Can rule out severe and profound losses only. Reflexive response can be inhibited, particularly with repeated presentation of stimulus. Tests of preference to assess hearing for this age group are therefore objective tests. Responses to sound in neonates and young infants  Eyeblink ( auropalpabrel reflex)  Gross motor response  Stilling  Startle  Eye movement/widening  Crying  Grimacing  (Heart rate changes/breathing changes) ASSESMENT OF HEARING

83. Objective Test Methods Otoacoustic emissions (OAEs) Can be used for any age child provided are settled and quiet. Active processes in the outer hair cells of the cochlea. OAEs are the sounds produced by these active processes. OAEs are measured in the ear canal in response to a stimulus presented to the ear. What are OAE's? Low-intensity sound generated by the cochlea (inner part of the ear) and measured in the ear canal.  First discovered in 1978. “Return or release of acoustic energy from the cochlea” produced by active processes within the cochlea. presence of OAEs indicates mechanically active outer hair cells (OHCs). Do not provide a measure of threshold. Presence of OAEs rules out a greater than mild hearing loss (not frequency specific). Absence of OAEs indicates a hearing loss but no indication of the degree of hearing loss. OAEs can be absent if there is blockage in the ear canal or middle ear (e.g. glue ear). OAEs abolished for hearing loss > 25dBHL.

84. Auditory Brainstem Response ( ABR) This test is used to screen newborn hearing, confirm hearing loss in young children, obtain ear-specific information in young children, and test children who cannt cooperate with behavioral test methods. The ABR test is a far-field recording of minute electrical discharges from numerous neurons The ABR result is not affected by sedation or general anesthesia . Infants and children from about 4 mo to 4 yr of age routinely are sedated to minimize electrical interference caused by muscle activity during testing. The ABR is recorded as 5-7 waves. Waves I, III, and V can be obtained consistently in all age groups; waves II and IV appear less consistently. For audiometry, the goal is to find the minimum stimulus intensity that yields an observable ABR.

85. Threshold ABR  Ideally baby is asleep.  Intensity of stimulus is reduced to find the minimum level at which the response is present to determine threshold.  Results give the average hearing at threshold across the range 1-4kHz.  Can also carry out bone conduction ABR to determine whether hearing loss is conductive, sensorineural or mixed.  Variations are available to provide frequency specific information but not widely used. Screening ABR  Clicks are presented at one intensity level only, typically 40dBnHL.  Clear Response – waveforms present and repeatable at screening level.  No Clear Response - waveforms are absent at screening level.  Those with hearing losses worse than a mild hearing loss will fail the hearing test.  May not detect mild hearing losses USES; Audiometry. It also is used in the differential diagnosis or monitoring of central nervous system pathology

86. Tympanometry and Acoustic reflexes Tympanometry provides a graph of the middle ear’s ability to transmit sound energy. A probe is inserted into the entrance of the external ear canal so that an airtight seal is obtained. The probe varies air pressure, presents a tone, and measures sound pressure level in the ear canal through the probe assembly  For assessing the middle ear and auditory nerves.  Non-invasive and can be performed when child awake but need to be relatively still.  A small probe is placed into the ear canal and the pressure is varied to move the eardrum and record a trace.  Assists in diagnosis of middle ear effusion (congestion behind the eardrum) or “glue ear”.  Presence or lack of acoustic reflexes can be a useful tool to assist in diagnostic procedures.

87. 6-18 months of age Distraction test  Traditional test of choice.  Based on the ability of this age group to localise sounds at and close to ear level.  Works on the fact that younger children need social reinforcement for responding to sounds.  In practice difficult above 12m.  Requires 2 testers.  A ‘distractor’ in front who controls the attention of the child, the test and assesses whether there has been a response  A ‘presenter’ behind the child presenting the sounds  Tests hearing to a range of sounds – frequency specific warble tones, high frequency rattle, voice.  Lots of potential flaws and possibilities for missing child with hearing loss.

88. 6-30 months of age Visual Reinforcement Audiometry (VRA)  A conditioned response to sound (usually head turn) is reinforced by a visual reward.  Conditioned by simultaneous presentation of sound and reinforcer (reward ).  Sounds typically presented from a loud speaker.  Once child is reliably conditioned for the test, only then can go on and start testing the child’s hearing.  Assesses hearing across frequency range, typically 0.5kHz to 4kHz which are important for speech and language access.  Present sound, child turns head, present re- inforcer once child has turned .  Can also be presented using insert earphones or headphones to obtain ear specific information.  Also can do bone conduction VRA (tests the underlying hearing - the cochlea, inner part of the ear ).  CORA – conditioned operative reinforcement audiometry – e.g. tactile reward, edible reward.  Tests the hearing in the better hearing ear

89. 30-36 months of age Performance audiometry  Can start trying at 24m (although limited success).  Conditioned voluntary response to a stimulus (warble tone) presented in the sound field.  E.g putting man in boat, peg in board when a sound is heard.  Assess hearing typically at 0.5, 1 (or 2), and 4kHz. (all if have co-operation of child).  Verbal comprehension not required – child is conditioned by demonstration. 36+ months of age Play audiometry  As for performance audiometry but with headphones.  Obtain ear specific information across frequency range.  Usually only get information at 3 frequencies for each ear for younger end of age group.  Test technique usually modified compared with adult version of test so that reliable results can be obtained in short a time as possible.

90. 5/7 years of age Puretone audiometry An audiometer is a device which produces pure tones,the intensity of which can be increased or decreased in 5db steps. Hearing thresholds are assessed as a function of frequency using pure tones (sine waves) at octave intervals from 250-8,000 Hz . hearing is assessed independently for each ear. Air-conducted signals are presented through earphones . bone–conducted signals are delivered to the ear through an oscillator that is placed on the head, usually on the mastoid. The amount of intensity that has to be raised above the normal level is a measure of degree of hearing impairment at that frequency. it is charted in the form of a graph called ‘ audiogram’.An audiogram provides the fundamental description of hearing sensitivity. the difference in thresholds of air and bone conduction is a measure of conductive deafness.(A-B gap). audiometer AUDIOLOGY SETUP

91. Speech-Recognition Threshold it is the lowest intensity level at which a score of approximately 50% correct is obtained on a task of recognizing spondee words. Spondee words are 2 syllable words or phrases that have equal stress on each syllable, such as baseball, hotdog. The SRT should correspond to the average of pure-tone thresholds at 500, 1,000, and 2,000 Hz. The SRT is relevant as an indicator of a child’s potential for development and use of speech and language. it also serves as a check of the validity of a test because children who malingerer might show a discrepancy between the pure-tone average and SRT.

92. References Diseases of ear,nose and throat by pl dhingra . Scott browns otolaryngology. Nelson text book of paediatrics. Clinical audiovestibulometry - anirban Biswas.

93. Thank you….