Anatomy and Pathophysiology for ICD-10 Module 11. Ear and Mastoid

Transcription

1 Anatomy and Pathophysiology for ICD-10 Module 11 Ear and Mastoid

2 Ear Anatomy

3 Outer Ear Ear Flap (Pinna) Ear Canal (Meatus) Middle Ear Tympanic Membrane (Eardrum) Hammer (Malleus) Anatomy and Physiology Major Parts of the Ear Anvil (Incus) Stirrup (Stapes) Inner Ear (Labyrinth) Cochlea Semicircular Canals Auditory Nerve

4 Outer Ear The outer ear or external ear is a visible portion of the ear, which serves as a protective organ for the eardrum. It collects and guides the sound waves into the middle ear. The outer ear consists of the following two parts

5 Ear Flap (Pinna)

6 Ear Flap (Pinna) The visible part of the ear that resides outside of the head The function of the pinna: Collect sound Perform spectral transformations to incoming sounds which enable the process of vertical localization to take place Acts as a funnel, amplifying the sound and directing it to the auditory canal The pinna works differently for low and high frequency sounds

7 Ear Flap (Pinna) For low frequencies, it behaves similarly to a reflector dish, directing sounds toward the ear canal For high frequencies, however, its value is thought to be more sophisticated Some of the sounds that enter the ear travel directly to the canal Others reflect off the contours of the pinna first A delay translates into phase cancellation

8 Ear Flap (Pinna) For low frequencies, it behaves similarly to a reflector dish, directing sounds toward the ear canal For high frequencies, however, its value is thought to be more sophisticated Some of the sounds that enter the ear travel directly to the canal Others reflect off the contours of the pinna first A delay translates into phase cancellation Where the frequency component whose wave period is twice the delay period is virtually eliminated.

9 Otolaryngology Normal Ear Canal

10 Ear Canal (meatus) The ear canal is a tube running from the outer ear to the middle ear The human ear canal extends from the pinna to the eardrum It is approximate 35 mm in length and 5 to 10 mm in diameter The human ear canal is divided into two parts The fibrocartilaginous part forms the outer third of the canal anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous

11 Ear Canal (meatus) The fibrocartilaginous part forms the outer third of the canal Anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous The cartilage is the continuation of the cartilage framework of pinna The bony part is much shorter in children and is only a ring in the newborn Size and shape of the canal vary among individuals

12 Ear Canal (meatus) Earwax, also known as cerumen, is a yellowish, waxy substance secreted in the ear canals Assist in cleaning and lubrication Provides some protection from bacteria, fungus, and insects

13 Middle Ear

14 Middle Ear The portion of the ear internal to the eardrum External to the oval window to the cochlea Transmit external sound energy to the components of the inner ear The mammalian middle ear contains three ossicles Three smallest bones in the human body

15 Eardrum Healthy Eardrum

16 Tympanic Membrane (Eardrum) Thin membrane that separates the external ear from the middle ear Its function is to transmit sound from the air to the ossicles inside the middle ear The malleus bone bridges the gap between the eardrum and the other ossicle The tympanic membrane is shaped like a flat cone pointing inwards towards the inner ear and is made up of three layers 1) Cutaneum ~ skin 2) Radiatum, circulare ~ collagen fibres 3) Mucosum, epithelium

17 Hammer (Malleus)

18 Hammer (Malleus) Hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum Transmits the sound vibrations from the eardrum to the incus

19 Anvil (Incus)

20 Anvil (Incus) Is the anvil-shaped small bone or ossicle in the middle ear Connects the malleus to the stapes Transmits sound vibrations from the malleus to the stapes

21 Stapes (Stirrups) Normal Stape Abnormal Stape

22 Stapes (Stirrups) Transmits the sound vibrations from the incus to the membrane of the inner ear Stabilized by the stapedius muscle, which is innervated by the facial nerve The stapes is the smallest bone in the body Pronounced stay-peas

23 Inner Ear (Labyrinth)

24 Inner Ear (Labyrinth) The innermost part of the vertebrate ear System of passages comprising two main functional parts The cochlea, dedicated to hearing The vestibular system, dedicated to balance

25 Cochlea

26 Cochlea Is the auditory portion of the inner ear It is a spiral-shaped cavity in the bony labryinth A core component of the cochlea is the Organ of Corti, the sensory organ of hearing Filled with a watery liquid, which moves in response to the vibrations coming from the middle ear The walls of the hollow cochlea are made of bone, with a thin, delicate lining of epithelial tissue

27 Middle Ear The malleus (hammer) articulates with the incus and is attached to the tympanic membrane (eardrum), from which vibrational sound pressure motion is passed The incus (anvil) is connected to both the other bones The stapes (stirrup) articulates with the incus and is attached to the membrane of the fenestra ovalis, the elliptical or oval window or opening between the middle ear and thevestibule of the inner ear

28 Semicircular Canal

29 Semicircular Canal Three half-circular, interconnected tubes located inside each ear The three canals are the horizontal semicircular canal (also known as the lateral semicircular canal), superior semicircular canal (also known as the anterior semicircular canal), and the posterior semicircular canal Each canal is filled with a fluid called endolymph and contains a motion sensor with little hairs The semicircular canals are a component of the bony labryinth

30 Auditory Nerve

31 Auditory Nerve A nerve in the head that carries signals from the cochlea of the inner ear to the brain A sensory nerve, one which conducts to the brain information about the environment Arises from within the cochlea and extends to the brainstem

32 Disease and Treatments of the Ear

33 Impacted Cerumen

34 Impacted Cerumen An atypical accumulation of cerumen in the canal of the outer ear. The ear wax hardens and has a tendency to prevent sound waves from reaching the tympanic membrane

35 Impacted Cerumen Signs and Symptoms If the secretions accumulates excessively, a gradual loss of hearing may occur and the patient may have a feelig that the ear is plugged and may experience tinnitus or an earache (otalgia) Impacted cerumen is a common cause of conductive hearing loss

36 Impacted Cerumen Treatment If the cerumen adheres to the wall of the ear canal, it may have to be softened first with oily drops, or hydrogen peroxide and then irrigated with water to accomplish removal Any hearing loss caused by the impaction is alleviated after removal of cerumen

37 Impacted Cerumen Prognosis The prognosis for removal is positive Hearing usually improves once the ear canal is clear of the impacted ear wax. Recurrence is likely so periodic examinations may be necessary

38 Otitits Externa

39 Otitis Externa Inflammation of the external ear canal Condition is usually accompanied by an infectious process

40 Otitis Externa Signs and Symptoms Severe pain Red, swollen ear canal Hearing loss Fever Pruritus Drainage from the ear may be either wax or purulent

41 Otitis Externa Diagnosis Otologic examination and a history of symptoms confirm the diagnosis. If a bacterial infection is suspected, a culture of the material found in the canal may be needed to determine how to properly treat the infection

42 Otitis Externa Treatment The ear canal must be kept clean and free from water Antibiotic or steroid eardrops and systemic antibiotics may be prescribed Tends to recur and can become chronic

43 Otitis Externa Prognosis Prognosis is positive with treatment Chroinic otitis externa may develop with repeated irritation by earphones, earplugs, or hearing aids

44 Otitis Externa Prevention Keep the ear clean and dry Keep earphones, earplugs, and hearing aids clean Use of another s earphones or earplugs is discouraged

45 Swimmer s Ear

46 Swimmer s Ear Inflammation and resulting infection of the outer ear canal after water has been entrapped during

47 Swimmer s Ear Signs and Symptoms Severe pain Red, swollen ear canal Hearing loss Fever Pruritis Drainage that may be watery or purulent

48 Swimmer s Ear Treatment Keep ear canal clean and dry after swimming Antibiotic or steroid eardrops and systemic antibiotics Can become chronic for those with repeated exposure to water

49 Otitis Media

50 Otitis Media Most common reason for visits to physicians by children and can be experienced by adults Classified as either serous or suppurative Nonsuppurative, the fluid is relatively clear and sterile Suppurative, the fluid is purulent The only symptom maybe a feeling of fullness or pressure and some degree of hearing loss

51 Otitis Media Diagnosis Otoscopy reveals the presence of a fluid-filled middle ear Pearl-gray eardrum is inflamed and may be bulging Fluid bubbles may be visible through the membrane If a culture is taken, white blood count would be elevated Measurement with tympanogram

52 Otitis Media Treatment Analgesics and deongestants Antibiotics Surgical evacuation of fluid for the more severe cases Myringotomy tubes Removal of hypertrophic adenoids is a therapeutic measure

53 Otosclerosis

54 Otosclerosis Primarily affects the stapes or third bone or ossicle in the middle ear Movement is impaired, which causes diminished conduction of sound waves and results in hearing loss

55 Otosclerosis Signs and Symptoms Abnormal growth of spongy bone forms around the oval window Ankylosis produces conductive deafness Gradual hearing loss Loss of low or soft sounds Tinnitus (ringing in the ear) Onset begins after puberty and before 35 years of age

56 Otosclerosis Treatment The only treatment that cures otosclerosis is a surgical procedure called a Stapedectomy Removes the diseased stapes and replaces it with a prosthesis

57 Benign Paroxysmal Positional Vertigo (BPV)

58 Benign Paroxysmal Positional Vertigo Benign positional vertigo is usually a vestibular system disorder. The patient complains of his/her head spinning, becoming worse with movement of the heard

59 Benign Paroxysmal Positional Vertigo Signs and Symptoms Spinning sensation with movement of the head Dizziness Feel that their body is moving with eyes open Nausea, vomitting, and involuntary eye movement

60 Benign Paroxysmal Positional Vertigo Diagnosis History and examination Audiogram or other means of hearing testing Testing to rule out CNS involvement CT, MRI scan of the head MRA scan of the brain blood vessels Caloric stimulation test

61 Benign Paroxysmal Positional Vertigo Treatment Antihistamines (Antivert, Dramamine) Anticholinergics (Scopolamine) Benzodiazepines (Compazine) Exercises where the individual repeatedly turns the head from side to side may also be helpful

62 Ruptured Tympanic Membrane (Ruptured Eardrum)

63 Ruptured Tympanic Membrane (Ruptured Eardrum) Any type of tear or injury to the eardrum causes a breach in the integrity of the membrane Results in pressure, force, or insult from the exterior aspect, or it may be caused by increased pressure within the middle ear

64 Ruptured Tympanic Membrane Signs and Symptoms Slight pain Partial loss of hearing Discharge or bleeding from the ear

65 Ruptured Tympanic Membrane Diagnosis Visual examination of the ear with an otoscope confirms the diagnosis Audiometry

66 Ruptured Tympanic Membrane Treatment Antibiotic Patch may be applied to the eardrum to aid in healing and improve hearing Tympanoplasty (involves actual grafting of tissue for eardrum repair)

67 Cancer of the Ear Cancer before surgery Cancer Reconstructin

68 Cancer of the Ear Tumors of the ear can occur in any part of the ear and may be benign or malignant Include: Cutaneous tumrs, ceruminal gland neoplasms, acoustic and facial neuromas and glomus tumors Most metastasize to the ear in secondary ear cancer

69 Signs and Symptoms Progressive hearing loss Chronic otic discharge Mass or lesion on ear exam Pain Pulsatile tinnitus

70 Diagnosis First identified because of the symptoms Biopsy Ct scan MRI used to evaluate the extent of the disease

71 Treatment Surgical excision Radiation therapy Nerve graft may be performed after surgical excision of a neuroma