heat. Clinical significance There are various visible ear abnormalities: traumatic injury infection wart, mole, birthmark scars, including keloids cyst skin tag sunburn, frostbite pressure ulcer, often from a poorly fitting hearing aid anotia, absent pinna microtia, underdeveloped pinna cryptotia, a pinna covered beneath the skin of the scalp Stahl's deformity, pointed pinna due to an extra fold of cartilage cupped or constricted ear deformity, a hooded superior helix preauricular pit preauricular tag Darwin's tubercle, protuberance on the anterior helix hypertrichosis, including hypertrichosis lanuginosa acquisita, a hairy pinna cauliflower ear, post-traumatic cartilage deformity tophus, nodule on the pinna related to gout chondrodermatitis nodularis chronica helicis (Winkler's nodule), a nodule initiated by solar damage actinic keratosis and cutaneous horn, premalignant lesions caused by solar damage benign and malignant neoplasm, including tumors, keratoacanthoma, carcinoma In other species Visible auricles are a common trait in mammals, particularly placental mammals and marsupials, but are poorly developed or absent in monotremes. Marine mammals usually have either reduced auricles or no auricals due to sound travelling differently in water than in air, as well as the fact that auricles would potentially slow them down in the water. Skin impressions show large, mouse-like auricles in Spinolestes. External auricles are absent in other tetrapod groups such as reptiles, amphibians, and birds. Additional images See also Earrings for pierced ears Ear stapling References External links drtbalu otolaryngology online Ear Auditory system