The models of experimental arthritis become important in the inquiry of different therapeutical alternatives and briefing of articulate pathogenesis. The possibility of measuring the injury of the articular cartilage makes the experimental model relevantly important, as well as the systemic biological effects that involve the different therapeutics: The radiological and histological aspects of the cartilage were researched in the model of Zynoman-induced arthritis in Rattus novergicus. Rats were submitted to the intra-articular injection (1.0ml) and sacrificed at different times, under anesthesia. The knee joints were surgically removed and processed for coloring in hematoxylin eosin (H&E). The radiographic analyses were carried out through images obtained with dental periapical film. The animals presented serious and gradual synovitis associated to the injury of the cartilage that was evaluated up to 14 days after the stimulation injection. The arthritis model by Zymosan allows the study of the inflammatory alteration of the synovial tissue and of the cartilage. In the presence of Zymosan, the juxtarticular and periarticular tissues develop similar alterations to those found in the autoimmune diseases.