Ear Flashcards
What nerves carry general sensation from the ear?
Cervical spinal nerves C2-3
Vagus
Trigeminal (auricotemporal)
Glossopharyngeal (tympanic)
What makes up the external ear?
Pinna
External auditory meatus
Lateral surface of tympanic membrane
What is the role of the external ear?
Collect, transmit and focus sound waves onto tympanic membrane
What is a pinna haematoma also known as?
Cauliflower ear
What causes a pinna haematoma?
Blunt injury to the pinna
What is a pinna haematoma?
Accumulation of blood between cartilage and its overlying perichondrium
What is the risk of a pinna haematoma?
Subperichondrial haematoma deprives cartilage of its blood supply
Risk of necrosis
How is a pinna haematoma managed?
Drainage and compression to prevent re-accumulation of blood
What is the external acoustic meatus?
Connects outer ear to tympanic membrane
How long is the external acoustic meatus?
~2.5 cm in length
What lines the external acoustic meatus?
Keratinising stratified squamous epithelium
What forms the structure of the external acoustic meatus?
Outer 1/3 = cartilaginous
Inner 2/3 = bony
What is the shape of the external acoustic meatus?
Sigmoid
How is the external acoustic meatus protected?
Cartilage part is lined by hair, sebaceous and ceruminous glands
What are ceruminous glands?
Wax producing glands
What are common conditions affecting the external acoustic meatus?
Wax
Otitis externa
What is otitis externa?
Inflammation of the external acoustic meatus
What is otitis externa also known as?
Swimmer’s ear
What can cause otitis externa?
Water trapped in ear
Damage to skin in ear
Skin problems
Wax build up
What are the symptoms of otitis externa?
Itching/pain in ear canal Watery discharge from ear canal Dry flaky skin around outside of ear and in canal Reduced hearing Discomfort when moving jaw
How is otitis externa managed?
Antibiotic + steroid ear drops
What are common abnormalities of the tympanic membrane?
Perforation
Bulging - due to otitis media
What is the middle ear?
Air filled cavity between tympanic membrane and inner ear containing ossicles
What is the role of the middle ear?
Amplify and relay vibrations from the tympanic membrane to the oval window tof the cochlea
What bones make up the ossicles?
Malleus
Incus
Stapes
What muscles are involved in the middle ear?
Tensor tympani
Stapedius
What is one of the most common causes of acquired hearing loss in young adults?
Otosclerosis
What is otosclerosis?
Condition where ossicles are fused at articulations due to abnormal bone growth
What bone is most commonly effected by otosclerosis?
Stapes