Transcript for:
Understanding Ear Anatomy and Pathologies

hi everyone my name is Jade and I'm medical student in Leicester in this video I will cover the anatomy of the ear and pathologies affecting the air [Music] let's start with the anatomy the ear is a unique organ in the body that allows us to hear while also being partly responsible for our sense of balance the ear can be divided into three parts external middle and in air the external air can be further divided into two parts the Oracle or Pinner which is the visible part of the ear and the external auditory meatus which is the part of the ear canal lateral to the eardrum or tympanic membrane the oracles funnel shape helps to capture and direct sound waves to the eardrum the Oracle is mainly cartilaginous with the exception of the fleshy lobule the external auditory meatus is an s-shaped canal the outer third of the canal is lined with cartilage and the inner two-thirds by temporal bone the tympanic membrane separates the middle ear from the external ear the tympanic membrane is a sheet of connective tissue that can be seen on a Tosca pea the middle is role is to transmit and amplify bration z' from the tympanic membrane to the inner ear it contains the smallest bones of the body malleus incus and stapes these bones known as the ossicles connect the tympanic membrane to the oval window of the cochlea the movement of the ossicles can be partially restricted by the tensor tympani and stapedius muscles which both contract in response to loud noises and excess vibration to prevent damage to the structures of the inner ear tensor tympani is innovated by a branch of the mandibular nerve and stapedius is innovated by a branch of the facial nerve there are many important structures surrounding the middle ear superiorly the brain can be found separated by the petrous part of the temporal bone therefore fractures of the cranial floor can allow the middle ear to communicate with the brain and lead to severe infection like meningitis or brain abscesses inferiorly the internal jugular vein is found laterally there's the tympanic membrane medially there's the facial nerve which can therefore be affected in otitis media anteriorly there is a thin plate of bone with an opening for the eustachian tube separating middle ear from the internal carotid artery the eustachian tube connects middle ear to the nasopharynx and its role is to equalize the pressure between the middle layer and the atmosphere and prevent tympanic membrane rupture in children the eustachian tube is narrow and horizontal so children are more prone to middle ear infections that is otitis media the mastoid air cells sit posteriorly to the middle ear separated from it by a thin layer of bone although there is a small opening superiorly allowing communication between the two areas the mastoid air cells are a collection of air filled spaces in the mastoid process of the temporal bone the inner ear is responsible for converting vibrations into nerve signals so the brain can interpret the sounds and it also helps with balance the inner ear has two main components the vestibular apparatus and the cochlear the cochlea converts vibrations on the oval into action potentials which are perceived as sound the vibrations on the oval window causes movements of fluid in the cochlea and movement of stereocilia to generate action potentials signals are sent to the primary auditory cortex to make sense of the input via the vestibular cochlear nerve that is cranial nerve 8 the vestibular apparatus is involved in maintaining our balance and sense of position it's made up of the semicircular ducts the saccule and utricle the semicircular canals are filled with fluid called endolymph which moves when the head moves stimulating stereocilia and sending signals to the brain to interpret the position of the head by the vestibular cochlear nerve now let's move on to some pathologies of the ear otitis externa also known as swimmers ear is an infection of the external auditory meatus with bacteria such as Pseudomonas and Staphylococcus aureus or fungi such as Aspergillus and Canada patients may present with oat Alger and a Turia otitis externa is a clinical diagnosis however consider taking an ear swab to determine the causative organism if medical management fails condition is severe or if otitis externa is recurrent or chronic first-line management for acute otitis externa is micro suction of debris in the ear canal and simple analgesia like paracetamol or ibuprofen if this is insufficient then consider prescribing a topical antibiotic like acetic acid 2% spray with or without a topical corticosteroid for at least 7 days you can also give the patient self-care advice to prevent future infections and aid recovery such as not using cotton buds to clean the air professional removal of earwax if this is a problem using earplugs when swimming and trying to get chronic skin conditions like eczema psoriasis under control otitis externa can lead to complications such as malignant otitis externa patients with diabetes or immuno compromised are at an increased risk of this complication in malignant otitis externa the infection invades bone and causes osteomyelitis trauma to the air resulting in pinna hematoma can become an ear deformity known as cauliflower ear if it's not urgently drained and compressed to prevent reoccur malaysian of blood deformity occurs because cartilage depends on overlying perichondrium for nutrients to maintain its cells however in pinna hematomas blood collects between the cartilage and the perichondrium starving the cartilage of oxygen and leading to cell de and cartilage necrosis now let's move on to pathologies of the middle ear otitis media is infection of the middle ear with pathogens that commonly affect the respiratory regions such as influenza virus him awfully influenza or Steph Allah coccus demony most cases are viral however patients may present with oat Alger fever and conductive hearing loss in younger children they may appear unwell difficult to settle and pull on one ear on a Tosca pea there'll be a bulging red tympanic membrane to manage otitis media you may decide to manage conservatively as in most cases it is self resolving sixty percent of cases of at Isis media will improve within 24 hours without antibiotics you can consider giving a delayed prescription for oral amoxicillin optimize analgesia antibiotic and steroid combination drops such as autumn eyes may also be used complications of a tightest media include perforated eardrum mastoid itis which pushes the air forward causes fever and swelling over the mastoid and sepsis Bell's palsy due to involvement of the facial nerve meningitis and brain abscesses in acute suppurative otitis media the patient will present with a history of gradually worsening ear pain or ear tugging in children with sudden appearance of discharge preceded by a popping sensation on a Tosca pea though may be mukou perryland watery discharge in the ear canal and perforation of the tympanic membrane scene it is managed in the same way as acute otitis media otitis media with effusion also known as glue ear is common in children due to the horizontal eustachian tube limiting drainage of the middle ear patients will present with conductive hearing loss poor speech development and at alger on a Tosca P you will see a retracted straw colored tympanic membrane it's useful to request a tympanogram and pure tone Audio Graham at Isis media where the fusion is usually self-limiting and resolves within three months provide the patient and their parents or guardians with verbal and written advice about glue ear and advice on how to minimize the impacts of hearing loss for example send a letter to the school requesting the child sit at the front of the class in cases of recurrent bilateral at Isis media with effusion then surgical intervention that is the insertion of grommets may be appropriate hearing aids may also be considered unilateral glue in an adult is worrying and should warrant further investigations as it could be a sign of nasopharyngeal malignancy cholesteatoma is a non cancerous growth of squamous epithelium that is behind the attic of the tympanic membrane patients present with conductive hearing loss foul-smelling persistent utter ear as well as possibly vertigo or facial nerve palsy they will not complain of any pain on a Tosca P there will be a brown irregular mass at the upper attic of the tympanic membrane it's a surgical emergency as invades surrounding tissue and bone like the mastoid bone and there is a high rate of recurrence complications of the surgical procedure to remove the cholesteatoma include hyperacusis vertigo tinnitus loss of taste and hearing loss otosclerosis refers to a gradual fusion of the stay piece of the middle ear to the oval window leading to gradual conductive hearing loss and tinnitus risk factors for otosclerosis include family history and pregnancy treatment is with stapedectomy and insertion of a prosthesis or hearing aids if bilateral deafness vertigo refers to a sensation of movement when stationary patients may feel unsteady and nauseous dizziness without sensation of movement is not vertigo it may be due to cardiovascular causes such as arrhythmias or postural hypotension blood pressure medications anxiety or intoxication among other causes one cause of vertigo is benign paroxysmal positional vertigo where crystals in the semicircular canals move when the patient turns the head stimulating stereocilia inappropriately patients present with intermittent bursts of vertigo they do not have any hearing loss or tinnitus you can perform the Dix Hall Pike test to confirm the diagnosis torsional nystagmus in the examination is indicative of BPPV BPPV can be managed by regularly performing the applse manoeuvre vestibular neuritis is another cause of vertigo and it refers to inflammation of the vestibular cochlear nerve patients will present with acute onset of severe vertigo vomiting diarrhea without any hearing loss or tinnitus it is self resolving although bed rest may be necessary and it would be sensible for the patient to avoid driving especially when they're dizzy labyrinthitis is a rare infection of the inner ear causing vertigo and permanent sensorineural hearing loss and all tinnitus on examination the patient will have horizontal nystagmus sensorineural hearing loss and an impaired vestibular cochlear reflex it's a self resolving infection so management may just include conservative management advice including avoiding driving resting during periods of vertigo and short-term prochlorperazine for severe episodes hearing loss can be classified as either sensory neural or conductive sensory neural indicates a problem with the nerve therefore it will be caused by pathologies involving the inner ear or cranial nerve 8 for example acoustic neuroma or many as disease conductive indicates a problem with the sound getting to the nerve therefore it will be caused by pathologies involving the middle or external ear for example ear wax but itis media or externa you can differentiate between the tube ironies and webos tuning fault tests in a conductive hearing loss Reba's will lateral eyes to the affected ear and renny's will show bone conduction is better than air conduction in a sensory neural hearing loss weavers will lateral eyes to the unaffected ear and Reni's will show air conduction is better than bone conduction although the air conduction isn't as loud as it is in the unaffected ear acoustic neuroma is a benign mass of Schwann cells that can cause a patient to have a unilateral sensory neural hearing loss vertigo tinnitus and an absent corneal reflex important investigations to be done include MRI of the cerebellopontine angle and audiometry management is either with conservative management surgery or radiotherapy drugs like cisplatin gentamicin or furosemide can also cause sensorineural hearing loss many as disease is a disease of unknown etiology that causes a buildup of endo lymph within the membranous labyrinth of the in-air patients present with recurrent episodes of unilateral sensory neural hearing loss vertigo oral fullness and tinnitus in association with vomiting and diarrhea on examination the patient will have rotational vertigo and a positive Romberg's test buccal or intramuscular prochlorperazine can be given in acute attacks and beta his scene and vestibular rehabilitation exercises can be used for prevention of attacks the patient should inform the DVLA about the condition and will need to avoid driving until symptom control is achieved thanks for watching