The Physiology of the Human Heart
The Anatomy of the Female Pelvis
The Anatomy of the Middle Ear

The Anatomy of the External Ear

Your two ears allow you to hear sounds and wear really cool earrings. The external ear includes the auricle as well as the external acoustic meatus, also known as the ear canal, which ends at the tympanic membrane separating the external ear from the middle ear.

Actually, there’s more to an ear than the external part you see on the sides of your head; most of the structures lie inside the middle ear and the inner ear.

The auricle (or pinna) is the part of the ear that you see — it helps transfer sound waves to the external acoustic meatus. It’s covered with skin and it has the following landmarks:

image0.jpg
  • Concha: The deepest depression, just posterior to the opening of the meatus

  • Helix: The elevated cartilaginous margin around the posterior and superior part of the auricle

  • Lobule: The ear lobe, containing fibrous tissue, fat, and blood vessels

  • Tragus: The small projection that lies anterior to the meatus

Sound waves enter the ear through the external acoustic meatus. A normal meatus is about 2 or 3 centimeters long, and it meets the tympanic membrane. The lateral part of the meatus is cartilaginous, and the deeper parts are bony. It’s lined with skin that contains ceruminous and sebaceous glands, which produce cerumen, or earwax.

The tympanic membrane is a thin oval membrane about 1 centimeter in diameter. The external side is covered with thin skin, and the internal side is covered with mucous membrane.

If you look at the tympanic membrane with an otoscope in a normal, healthy ear, you see a cone of light on the membrane going anteriorly and inferiorly. Superior to the cone of light, you see the flaccid part that has fewer fibers than the rest of the membrane, which is called the tense part.

blog comments powered by Disqus
The Anatomy of the Male Pelvis
The Anatomy of the Human Eye
The Anatomy of the Gallbladder and Pancreas
The Anatomy of the Inner Ear
The Location of the Thyroid and Parathyroid Glands
Advertisement

Inside Dummies.com