Ear Anatomy and Examination

Ear Anatomy

• The ear consists of the auricle, tympanic membrane, and mastoid bone
• The mastoid bone contains the sinudural, perisinus, superficail dural, and zygomatic sinuses

Ear Examination

• Ear examination can be performed using an ear speculum, otoscope, microscope, and Siegle's speculum
• Otoscopy is used to visualize the tympanic membrane
• Tympanometry measures the movement of the eardrum and the pressure in the middle ear

Hearing Tests

• Rinne's test compares air conduction to bone conduction
• Weber's test determines whether sound is localized to one ear
• Pure tone audiometry tests hearing thresholds for different frequencies
• Tympanometry can also be used to assess eustachian tube function

Ear Disorders

• Microtia is a congenital deformity of the auricle
• Pre-auricular sinus is a small pit or dimple in front of the ear
• Perichondrial hematoma is a collection of blood between the auricle and its cartilage
• Cauliflower ear is a deformity of the auricle due to trauma

External Ear Infections

• Impetigo is a bacterial skin infection
• Erysipelas is a bacterial infection of the skin and lymphatic vessels
• Rodent ulcer is a type of skin cancer
• External ear carcinoma is a type of skin cancer
• EAC stenosis is a narrowing of the external auditory canal
• EAC atresia is a congenital absence of the external auditory canal
• Foreign bodies in the ear can cause infections and other complications

Middle Ear Infections

• Diffuse otitis externa is an inflammation of the external auditory canal
• Frunculosis is an infection of the hair follicles in the ear canal
• Otomycosis is a fungal infection of the ear canal
• Eczematous otitis externa is an inflammation of the ear canal due to eczema
• Seborrheic dermatitis is an inflammatory skin condition

Temporal Bone Fractures

• Temporal bone fractures can be longitudinal or transverse
• Longitudinal fractures involve the otic capsule and may damage the ossicles
• Transverse fractures involve the petrous bone and may damage the facial nerve

Traumatic Perforations

• Traumatic perforations of the tympanic membrane can occur due to injury
• Otoscopy can be used to visualize the tympanic membrane and assess for perforations

Acute Otitis Media

• Acute otitis media is an infection of the middle ear
• It can cause a bulge in the tympanic membrane, which can rupture and cause discharge
• Eustachian tube dysfunction can contribute to the development of acute otitis media

Chronic Otitis Media

• Chronic otitis media can cause central or attic perforations of the tympanic membrane
• Cholesteatoma is a complication of chronic otitis media that involves a pocket of epithelial cells in the middle ear
• Marginal posterior perforations are common in chronic otitis media

Complications of Otitis Media

• Mastoiditis is an infection of the mastoid bone
• Petrositis is an infection of the petrous bone
• Labyrinthitis is an infection of the inner ear
• Facial nerve paralysis can occur due to otitis media

Other Ear Disorders

• Secretory otitis media is a type of chronic otitis media characterized by a thick, sticky fluid in the middle ear
• Glomus tympanicum is a benign tumor that grows on the promontory of the middle ear
• Middle ear carcinoma is a rare type of cancer
• Otosclerosis is a condition that affects the middle ear bones and can cause hearing loss