1. 본 질병의 다른 이름; Chodritis. 2. 본 질병의 개요 및 역학; The natural incidence of gross ear deformity in outbred SD rats which were obtained from Chales River Breeding Laboratories, Wilmington, Massachusettes, was reported to be 98 of 2733 (3.6%) males and 82 of 2148 (3.8%) females (Chiu and Lee 1984). 3. 원인; Naturally, experimentally. 4. 병리기전; Inflammation $longrightarrow$ the cartilage plate is destroyed $longrightarrow$ for mation of nodular masses of proliferative rissues followed by osseuos metaplasia. 5.임상증상; Both pinnae are thickened, nodular, and droopy. 6. 병리조직소견; Focal of multkfocal, granulomatous inflammation; fibrovascular, fibrochondrous, chondrous, of chondroosseous tissue sl or a mixture of these 7.진단; Both pinnae are thickened, nodular, and droopy. 8. 감별진단; Fibrochondroma, chondroma, chondrosarcoma. (중략)