If you had a patient who had an inability to produce synovial fluid, this would be likely caused by a disorder of the

The inability to produce the fluid that retains most joints moist would probably be causes by a disorder of the synovial membrane. The synovial membrane is a dedicated connective tissue that lines the inner surface of capsules of synovial joints and tendon sheath. It sorts straight contact with the synovial fluid lubricant which it is mainly accountable for upholding. 

Can you put the picture?