Pinna (anatomy) in the context of Ear infection

Earrings are jewelry that can be worn on one's ears. Earrings are commonly worn in a piercing in the earlobe or another external part of the ear, or by some other means, such as stickers or clip-ons. Earrings have been worn across multiple civilizations and historic periods, often carrying a cultural significance. They are for both men and women.

Locations for piercings other than the earlobe include the rook, tragus, and across the helix (see image in the infobox). The simple term "ear piercing" usually refers to an earlobe piercing, whereas piercings in the upper part of the external ear are often referred to as "cartilage piercings". Cartilage piercings are more complex to perform than earlobe piercings and take longer to heal.

An eared seal, otariid, or otary, is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds. They comprise 15 extant species in seven genera (another species became extinct in the 1950s) and are commonly known either as sea lions or fur seals, distinct from true seals (phocids) and the walrus (odobenids). Otariids are adapted to a semiaquatic lifestyle, feeding and migrating in the water, but breeding and resting on land or ice. They reside in subpolar, temperate, and equatorial waters throughout the Pacific and Southern Oceans, the southern Indian, and Atlantic Oceans. They are conspicuously absent in the north Atlantic.

The words "otariid" and "otary" come from the Ancient Greek ὠτάριον (ōtárion), meaning "little ear", referring to the small but visible external ear flaps (pinnae), which distinguishes them from the phocids.

Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly. Together with the fur seals, they make up the family Otariidae, eared seals. The sea lions have six extant and one extinct species (the Japanese sea lion) in five genera. Their range extends from the subarctic to tropical waters of the global ocean in both the Northern and Southern hemispheres, with the notable exception of the northern Atlantic Ocean.

Sea lions have an average lifespan of 20–30 years. A male California sea lion weighs on average about 300 kg (660 lb) and is about 2.4 m (8 ft) long, while the female sea lion weighs 100 kg (220 lb) and is 1.8 m (6 ft) long. The largest sea lions are Steller's sea lions, which can weigh 1,000 kg (2,200 lb) and grow to a length of 3.0 m (10 ft). Sea lions consume large quantities of food at a time and are known to eat about 5–8% of their body weight (about 6.8–15.9 kg (15–35 lb)) at a single feeding. Sea lions can move around 16 knots (30 km/h; 18 mph) in water and at their fastest they can reach a speed of about 30 knots (56 km/h; 35 mph). Three species, the Australian sea lion, the Galápagos sea lion and the New Zealand sea lion, are listed as endangered.

Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family Otariidae. They are much more closely related to sea lions than true seals, and share with them external ears (pinnae), relatively long and muscular foreflippers, and the ability to walk on all fours. They are marked by their dense underfur, which made them a long-time object of commercial hunting. Eight species belong to the genus Arctocephalus and are found primarily in the Southern Hemisphere, while a ninth species also sometimes called fur seal, the Northern fur seal (Callorhinus ursinus), belongs to a different genus and inhabits the North Pacific. The fur seals in Arctocephalus are more closely related to sea lions than they are to the Northern fur seal, but all three groups are more closely related to one another than they are to true seals.

The antihelix (anthelix) is a part of the visible ear; the pinna.The antihelix is a curved prominence of cartilage parallel with and in front of the helix on the pinna.

The antihelix divides above into two legs or crura; the crura antihelicis, between which is a triangular depression, the fossa triangularis.

The tragus is a small pointed eminence of the external ear, situated in front of the concha, and projecting backward over the meatus. It also is the name of hair growing at the entrance of the ear. Its name comes from the Ancient Greek tragos (τράγος), meaning 'goat', and is descriptive of its general covering on its under surface with a tuft of hair, resembling a goat's beard. The nearby antitragus projects forwards and upwards.

Because the tragus faces rearwards, it aids in collecting sounds from behind. These sounds are delayed more than sounds arriving from the front, assisting the brain to sense front vs. rear sound sources.

Perichondritis is inflammation of the perichondrium, a layer of connective tissue which surrounds cartilage. A common form, auricular perichondritis (perichondritis auriculae) involves infection of the pinna due to infection of traumatic or surgical wound or the spread of inflammation into depth (e.g. Infected transcartilaginous ear piercings). It may lead to severe deformation of the pinna if not treated vigorously with IV antibiotics. The causative organism is usually Pseudomonas aeruginosa. A rare form is laryngeal perichondritis (perichondritis laryngis). It develops suddenly due to an injury, virulent organisms or compromised immune status of the host, and also affects cartilage of the larynx. This may result in deformations and stenoses.