Intrachondral Rupture and Hematoma Formation in the External Ear of Dogs

Abstract

Biopsies from auricular hematomas in 36 dogs and the whole ears from 4 dogs with recent untreated or old healed unilateral hematomas were studied microscopically. A predominantly intrachondral location of the hematomas was demonstrated. They apparently arise as sequelae to primary, traumatically induced, intrachondral ruptures with subsequent cleavage of the cartilage plate. Occasionally, in some areas, separation occurs between the perichondrium and the corium. The hemorrhage presumably results from rupture of small blood vessels where these pass through the foramina in the cartilage. No difference in histological appearance was found between auricular cartilage from affected dogs and normal dogs in the same age range. No breed predisposition was demonstrable.