Downloaded 72 times
More Related Content
![EAR_ANAT_PP[1].pptx](https://cdn.slidesharecdn.com/ss_thumbnails/earanatpp1-230506175502-99011333-thumbnail.jpg?width=640&height=640&fit=bounds)
![CTEV [ clubfoot] DR ARUN LAL ,DR MOHAMED ASHRAF travancore medical college k...](https://cdn.slidesharecdn.com/ss_thumbnails/ctevclubfootdrarunlaldrmohamedashraftravancoremedicalcollegekollamkeralaindia-260208063247-18fc466c-thumbnail.jpg?width=640&height=640&fit=bounds)
Ear
- 1. 1 THE EAR Major RahulJha Graded Specialist Anatomy ACMS
- 2. Introduction • Organ ofhearing and also plays an important role in equilibrium. • Divided into three parts:- – External ear. – Middle ear. – Internal ear. • External ear consists of Pinna/auricle. • Tympanic membrane at the medial end of EAM. • Middle ear – an air filled space containing ear ossicles. • Communicates with the nasopharynx through auditory tube. • Internal ear consists of bony labyrinth & fluid filled labyrinth. 2
- 3.
- 4. EXTERNAL EAR Components –Pinna –EAM –Concerned withreception of noise. 4
- 5.
- 6. 6 EXTERNAL AUDITORY MEATUS •Length: 2.5 cms • Parts – Cartilagenous : lateral 1/3rd – Bony: medial 2/3rd Bends – B/T lat 1/3rd & medial 2/3rd – 5 mm from TM Direction – Backwards & medially • To examine, pull ear. LAT MED
- 7. 7 EAMEpithelium – Adherent tobone & cartilage – Ceruminous glands – Secretions prevent entry of bacteria, make it waterproof Blood supply – Ant tympanic – Deep auricular – Post auricular Nerve supply Medial 1/4: • IX CN • Auricular br of X CN (Arnold’s) Lateral 3/4: • Roof: ATN • Floor: Great auricular N
- 8. Tympanic membrane • Thinsemi-transparent membrane which forms the partition between the EAM & the middle ear. • Placed obliquely at an angle of 55 degrees with the floor. • Faces forward, downward & laterally. 8 TYMPANIC MEMBRANE
- 9. 11 Angle of TMto EAM
- 10. 12 TYMPANIC MEMBRANE Subdivisions • Bymalleolar folds – Pars flaccida (Shrapnel’s membrane) • Present between folds • Lax area – Pars tensa • Rest of membrane • Tense due to – Attachment of handle of malleus – Radiating fibres of intermediate layer PF PT AMF PMF Line of attach of handle of malleus on medial surface
- 11. 13 TYMPANIC MEMBRANE Surfaces Lateral surface •Concave, directed down, forward & laterally Medial surface • Convex, max at umbo • Handle of malleus attached here • Chorda tympani is medial to handle of malleus
- 12. 14 Structure From lateral tomedial Outer cuticular layer • Lined by str squamous nonkeratinized epithelium Intermediate fibrous layer • Outer radiating, inner circular fibres Inner mucous layer • Lined by columnar epithelium with patchy ciliated Handle of malleus & chorda tympani lie b/t mucous & intermediate fibrous layer TYMPANIC MEMBRANE
- 13. 15 Outer cuticular layer Middlefibrous layer Inner mucous layer Deep circular fibres Superficial Radiating fibres Pars flaccida TM: STRUCTURE
- 14.
- 15. 17 Nerve Supply – Lateralsurface – ATN – Vagus N (auricular br) – Medial surface • IX CN (tympanic br-Jacobson’s N) • Chorda tympani Blood Supply – Deep auricular br of maxillary (lateral surface) – Ant tympanic Ar – Post auricular: stylomastoid br TYMPANIC MEMBRANE
- 16. 18 CLINICAL ANATOMY • ASOM –Pus discharged laterally • Myringotomy • Incision at posteroinferior quadrant –Prevent damage to chorda tympani –Rich blood supply: healing faster
- 17.
- 18. 20 MALLEUS • Head – Inepitympanic recess – Post surface: facet for incus- Incudomalleal jt: Saddle jt • Neck – against pars flaccida – Chorda tympani cross medial to neck • Handle – Project down & back till umbo – processes • lateral pr : Upper end, handle & lat pr attached to fibrous layer of TM, malleolar folds • Anterior pr : attachment of ant lig of malleus
- 19. 21 INCUS Body • In epitympanicrecess • Articulates anteriorly with head of malleus Short process • Lig attached to fossa incudis (post wall of TC) Long process • Hook medially, articulate with stapes • Incudostapedial joint: ball & socket
- 20. 22 STAPES • Head – Articulateswith lenticular nodule of incus • Neck – Stapedius attached to back of neck • Ant & post limbs • Foot plate – anchored to fenestra vestibuli by annular lig – syndesmosis
- 21. 23 MIDDLE EAR Biconcave boxlike cavity Location – Petrous temporal bone Parts – Roof – Floor – Walls • Anterior & Posterior • Medial & Lateral
- 22. 24 Canal for TT Auditory tube Aditus to antrum Mastoid antrum Mastoid cells Mastoid process EAM Middle ear (Tympanic cavity) MIDDLE EAR Ht & Length: 15 mm Medial & lateral walls: 2 mm Roof: 6 mm Floor: 4 mm
- 23. 25 Auditory tube Tegmen tympaniAditus to antrum Mastoid antrum Mastoid air cells Mastoid process Middle Ear ANT & POST WALLS & ROOF
- 24. 26 Epitympanic recess Aditus Auditory tube ICA Sup bulbof IJV VII CN ROOF & FLOOR
- 25. 27 Auditory tube Cochlea Semicircular canal Middleear Tympanic antrum Vestibule Stapes Tympanic membrane EAM Internal acoustic meatus Inner ear LATERAL & MEDIAL WALLS
- 26. 28 LATERAL & MEDIALWALLS
- 27.
- 28. 30 MIDDLE EAR: COMMUNICATIONS Anteriorwall • auditory tube Posterior wall • mastoid antrum Medial wall • inner ear Lateral wall • tympanic membrane
- 29. 31 Left ear: TMremoved Roof Floor Medial wall Ant wall Post wall
- 30. 32 MIDDLE EAR: WALLS& FEATURES
- 31. 33 Formed by – Tegmentympani • Thin bony plate of petrous temporal • Separates tympanic cavity from MCF • Pierced by lesser & greater petrosal nerves Applied – If unossified: spread of infection to meninges – Venous drainage to superior petrosal sinus through petrosquamous suture: infection to sinus ROOF
- 32.
- 33.
- 34. 36 FLOOR Formed by – Plateof bone above jugular fossa Relations – Anterior • Carotid canal – Posterior • IJV Tympanic canaliculus - tympanic br of IX CN enters Applied – Spread of infection to IJV: thrombosis
- 35. 37 Epitympanic recess Aditus Auditory tube ICA Sup bulbof IJV VII CN MIDDLE EAR: FLOOR
- 36. 38 ANTERIOR WALL Shortened byapproximation of roof & floor Anteriorly has post wall of carotid canal Features – Canal for • Tensor tympani • Auditory tube – Processus trochleariformis • Bony shelf extends back on medial wall & turns lateral: provide pulley for tensor tympani to get attached to handle of malleus
- 37. 39 POSTERIOR WALL Wider abovethan below Features 1. Aditus to mastoid antrum • Epitympanic part communicate with mastoid antrum 1. Facial canal: in lower part 2. Pyramid • Projects above facial canal • Contains stapedius, from apex tendon
- 38. 40 Left ear, TMremoved Roof Floor Medial wall Ant wall Post wall
- 39. 41 LATERAL WALL Components Tympanic Membrane Epitympanicrecess • Part above tympanic cavity – Contains » Upper half of malleus » Greater part of incus
- 40. 42 MEDIAL WALL Features 1. Promontory •Due to basal turn of cochlea • Tympanic plexus (IX CN) 1. Fenestra vestibuli (fossa ovalis) • Behind & above promontory • Closed by base of stapes & annular ligament 1. Fenestra cochleae (fossa rotunda) • Below & behind promontory • Closed by secondary TM (separate TC from scala tympani) 1. Sinus tympani • Depression behind promontory • Position of ampulla of post semicircular canal 1. Facial canal • Oblique part, run back & down above fenestra vestibuli 1. Processus trochleariformis
- 41. 43 Posterior Left ear, TMremoved roof floor Medial wall Ant wall Post wall
- 42.
- 43.
- 44.
- 45. 47 TENSOR TYMPANI Origin • Bony& cart part of AT, becomes tendon, hooks around processus trochleariformis Insertion • Handle of malleus: upper part N/S • Nerve to Medial pterygoid Actions • Pull handle of malleus, TM concave, makes tense • Increase tight adhesion of footplate to fenestra vestibuli – Hence dampens sound
- 46. 48 STAPEDIUS Origin • Interior ofhollow pyramid Insertion • Back of neck of stapes N/S • Facial nerve Actions • Retract neck of stapes from fenestra vestibuli • Paralysis: hyperacusis
- 47. 49 CLINICAL ANATOMY 1. Otitismedia 2. Otosclerosis 3. Injury to nerve to stapedius • Hyperacusis
- 48. 50 Normal TM Wax CLINICALANATOMY
- 49.
- 50.
- 51.
- 52.
- 53.