Anatomy of the Ear Quiz

See Pinna. Option B is correct: the pinna (also called the auricle) is the part of the external ear on the side of the head, and it acts to direct sound waves towards the external acoustic meatus. Most of it is made of elastic cartilage (a flexible type of cartilage). Useful landmarks to learn are the tragus, helix, concha and lobule. The path of sound then runs along the ear canal to the tympanic membrane, which turns the sound waves into vibration of the membrane. This is passed along the three ossicles (the tiny bones of the middle ear) to the oval window and the cochlea, where hair cells start the nerve signal along the vestibulocochlear nerve. A simple memory aid: pinna catches the sound, the eardrum turns it into vibration, the ossicles pass it on, and the cochlea turns it into a nerve signal.

• Pinna: The auricle, made of elastic cartilage, collects sound.
• Direction: It directs sound waves towards the external acoustic meatus.
• Next steps: The eardrum turns sound into vibration, and the ossicles pass it on to the cochlea.