The outer part of the ear is called the auricle, also known as the pinna. These two terms are used interchangeably in medicine, and both refer to the visible, curved structure on the side of your head. The auricle is just one component of the outer ear, which also includes the ear canal leading to the eardrum.
Parts of the Auricle
The auricle looks simple from the outside, but it’s actually made up of several named ridges, folds, and depressions that all serve a purpose. The outermost curved rim is the helix, which wraps around the top and side of the ear. Running roughly parallel to the helix, just inside it, is a smaller ridge called the antihelix.
The small, pointed flap that partially covers the opening of your ear canal is the tragus. Directly opposite, on the other side of the canal opening, sits a smaller bump called the antitragus. The bowl-shaped depression between these structures is the concha, and it funnels sound directly into the ear canal. At the bottom, the soft, fleshy part that hangs down is the lobule, commonly called the earlobe. Unlike the rest of the auricle, the lobule contains no cartilage, which is why it feels softer and more pliable.
What the Auricle Is Made Of
Most of the auricle is built from elastic cartilage, a type of cartilage rich in stretchy elastic fibers. This is what allows your outer ear to flex and spring back into shape rather than snapping when bent. It’s a different material from the stiffer hyaline cartilage found in joints and the windpipe. A thin layer of tissue called the perichondrium wraps around the cartilage, and skin sits tightly over the whole structure with very little fat underneath.
The Ear Canal
Beyond the concha, the ear canal (formally the external auditory meatus) extends inward about 2.5 centimeters to the eardrum. It has a diameter of roughly 0.6 centimeters. The outer portion is cartilaginous, while the inner portion is bone. In younger people, the canal is nearly circular in cross-section, but with age the cartilaginous part often becomes more oval.
The ear canal produces earwax through two types of glands working together. Sebaceous glands secrete an oily substance that keeps the skin inside your ear from drying out. Ceruminous glands, which are modified sweat glands, produce antimicrobial proteins that fight off bacteria and fungi. The resulting earwax waterproofs the canal lining, traps dust and debris before it can reach the eardrum, and gradually carries dead skin cells outward.
How the Outer Ear Collects Sound
The shape of the auricle isn’t decorative. Its ridges and curves catch sound waves and channel them into the ear canal, but more importantly, they alter sound in subtle ways that your brain uses to figure out where a sound is coming from. The folds of the auricle create tiny differences in how sound frequencies reach your eardrum depending on whether a noise comes from above, below, in front, or behind you. These are called spectral pinna cues.
Your brain relies on different information for different directions. Left-right location is mainly determined by differences in timing and volume between your two ears. But up-down and front-back location depends heavily on how the pinna’s shape filters the sound. Research has shown that when the pinna’s shape is altered with molds, people lose the ability to tell whether a sound is above or below them, even though they can still tell left from right. This is why the specific curves of your outer ear matter for spatial hearing.
How the Outer Ear Develops
The auricle begins forming near the end of the fourth week of embryonic development. Six small bumps of tissue, called auricular hillocks, emerge around the opening of the future ear canal. Three hillocks arise from one structure (the first pharyngeal arch) and eventually become the tragus, helix, and part of the concha. The other three come from the second pharyngeal arch and form the rest of the concha, the antihelix, and the antitragus. These six hillocks gradually enlarge and fuse together into the recognizable ear shape.
Common Outer Ear Problems
Because the auricle is exposed and has very little padding over its cartilage, it’s vulnerable to a few specific conditions.
Perichondritis is an inflammation of the perichondrium, the tissue layer surrounding the ear’s cartilage. It typically causes redness, swelling, warmth, and tenderness across the ear. One useful clue: perichondritis spares the earlobe, since the lobule has no cartilage. Cellulitis, by contrast, tends to involve the entire ear including the lobe. Perichondritis often follows trauma to the ear, whether from piercings, acupuncture, abrasions, burns, or insect bites.
Cauliflower ear is a deformity that develops when blood collects between the cartilage and perichondrium after an injury, usually from repeated blows to the ear in contact sports like wrestling or boxing. The trapped blood triggers an inflammatory reaction that deposits new, irregular fibrocartilage. Over time, this gives the ear a lumpy, thickened appearance. Once the deformity sets in, it’s permanent, which is why draining the blood collection quickly after an injury is important.