Ear Anatomy: Outer and Middle Ear

Outer Ear

• Components: Pinna and external auditory canal.
• Pinna: Outer, visible part; collects and channels sounds into the ear.
• Function: Funnels sound.

Middle Ear

• Location: Receives sound from the auditory canal.
• Function: Channels and amplifies sound.
• Key Structures:
  • Eardrum (tympanic membrane): Separates outer from middle ear; vibrates in response to sound.
  • Hammer, Anvil, Stirrup (Ossicles): Interconnected, tiny bones that vibrate to transmit sound waves to the fluid-filled inner ear. Also called the ossicles.
• Sound Transmission: Muscles operating ossicles transmit eardrum vibration to the oval window (opening of the inner ear).
• Amplification: Ossicles amplify sound to overcome resistance as sound moves from air (middle ear) to fluid (inner ear).
• Protection: Ossicle muscles can also decrease sound intensity to protect the inner ear.