ear

Pinna (Auricle): Part of the outer ear that picks up vibrations.
External Auditory Canal: Directs sound vibrations down to the eardrum (tympanic membrane).
Tympanic Membrane (Eardrum): Vibrates in response to sound waves.

Sound Transmission: Sound waves cause the tympanic membrane to vibrate, which in turn vibrates the following small bones:
  - Malleus (Hammer): Attached to the inner surface of the tympanic membrane.
  - Incus (Anvil): Struck by the malleus, moves as a result.
  - Stapes (Stirrup): Last of the small bones, pushes against the fluid in the inner ear through the oval window.
Communications: The middle ear connects to the throat via the eustachian tube.
Eustachian Tube: Equalizes air pressure in the middle ear with atmospheric pressure; susceptible to infections from the throat.
Pressure Changes: Rapid altitude changes or certain actions (blowing nose, sneezing) can cause pressure imbalances leading to:
  - Pain
  - Effusions
  - Hearing loss

Cochlea: A coiled structure that contains the organ of Corti, which has specialized nerve cells that transmit sound impulses to the auditory nerve.
Auditory Nerve: Carries impulses to the auditory center located in the temporal lobe of the cerebrum for sound interpretation.
Semicircular Canals: Three structures responsible for balance. They contain:
- Hair Cells: Receptors embedded in a gelatinous substance; they send signals to the brain when the head moves.
- Calcium Carbonate Crystals: Tiny grains on a gelatin surface; their movement due to head motion also stimulates hair cells.
Functions of Inner Ear:
- Sound transmission to enable hearing.
- Maintenance of balance through the semicircular canals.

Routine Examinations: Audiometry, Weber, Rinne tests assess hearing function.
Videonystagmography (VNG): Measures balance function; requires special goggles that track eye movements while warm and cool water or air is introduced into each ear canal.
Magnetic Resonance Imaging (MRI): Provides images of the brain and inner ear to identify pathologies.

Definition: Anything that occludes the ear canal opening, resulting in various symptoms.
Common Causes:
  - Insects
  - Impacted cerumen (earwax)
  - Foreign bodies (e.g., beans, peas, pebbles)
Symptoms: Discomfort, hearing loss, annoyance.
Treatment:
  - Use of Otoscope to evaluate and remove obstructions.
  - Techniques include gentle scraping with a cerumen spoon, irrigation (stopping if pain occurs), and using viscous lidocaine for insect removal.
  - Referral to an otolaryngologist if removal is challenging.

Definition: Reduced ability to perceive sound at normal levels; can be gradual or sudden.
Types of Hearing Loss:
  - Conductive Hearing Loss: Caused by inability to carry sound waves through ear structures due to:
    - Obstruction (e.g., earwax, foreign body).
    - Middle ear infections.
    - Otosclerosis.
  - Sensorineural Hearing Loss: Results from nerve transmission failures.
Presbycusis: Gradual hearing loss related to aging, particularly affecting high-frequency sounds.
Sudden Hearing Loss: Considered a medical emergency; possible causes include infections, trauma, brain tumors, toxicity, and vascular disorders.
Noise-Induced Hearing Loss: Caused by sustained exposure to noise exceeding 85-90 decibels; preventable with protective devices (earplugs).
Diagnostic Tools: Audiometers and Ryan & Weber tests assess both bone and air conduction.
Treatment Options:
- Removal of underlying obstructions for conductive loss.
- Possible use of hearing aids or cochlear implants for severe sensorineural loss.

Components:
- External: Microphone, speech processor, transmitter.
- Internal: Receiver-stimulator and electrode array.
Function: Converts sound into electric impulses that stimulate the auditory nerve, sending signals to the brain for interpretation.
Requirements: Intact auditory nerve; evaluation by an audiologist for candidacy; modest communication ability post-implant; 2% failure rate can result in loss of natural hearing.

Symptoms: Severe vertigo, tinnitus, episodic dizziness, nausea, and vomiting.
Demographics: Typically affects ages 30-50; both genders equally; 15-25% may affect both ears.
Pathophysiology: Possible abnormalities in inner ear fluids.
Treatment: Medications for fluid reduction, avoidance of triggers (caffeine, salt, alcohol), surgical options if symptoms persist (shunting, labyrinthectomy).

Description: Loss of equilibrium from motion (cars, boats, planes); symptoms include nausea and vomiting.
Etiology: Over-stimulation of inner ear receptors or confusion between visual and movement perception in the brain.
Management: Avoidance, stabilization of the head, visual fixation on stationary objects, and preventive medications (e.g., scopolamine).

Definition: Infection of the external auditory canal; causes pain and potential hearing loss.
Causes: Contamination from water, improper use of cotton swabs, prolonged moisture from earphones.
Treatments: Pain relief and antibiotic drops; management may include antifungal treatment if necessary.

Description: Infection of the middle ear, often linked with respiratory infections; symptoms include severe pain, fever, hearing loss, and possible tympanic membrane rupture.
Causes: Pathogens from throat infections; eustachian tube blockage leading to negative pressure and fluid buildup.
Treatment: Antibiotics (e.g., amoxicillin) and pain management; Myringotomy may be indicated for severe cases.
Pediatric Implications: Higher risk in infants due to horizontal eustachian tubes, potential for fluid reflux implicating ear infections.
Chronic Management: Tympanostomy tubes may be inserted for recurring cases.

Definition: Condition causing conductive deafness by immobilizing the stapes due to spongy bone formation.
Characteristics: Progressive hearing loss, often genetic; incidence is 10% in whites; affects females twice as often.
Treatment Options: Surgical stapes removal and insertion of an artificial substitute; hearing aids where surgery isn't feasible.

Nature: Age-related, sensorineural hearing loss characterized by high-frequency sound loss; often coexists with tinnitus.
Social Impact: Difficulty in understanding speech leading to potential depression due to communication issues.
Treatment: Hearing aids can assist if properly fitted; condition is irreversible but manageable with technology.