Serous tarsitis is characterized by three soft, fluctuating swellings between the ligaments of the femorotarsal joint. In some instances, this condition is heritable. It does not cause pain or lameness. In later life, there may be a predisposition to arthritis. Serous tarsitis is diagnosed by depressing the swelling of the joint capsule at one location and palpating the fluctuation that is seen at another. There is no successful treatment.