Characteristics of normal equine tarsal synovial fluid.

Physical, biochemical, and cytologic properties of synovial fluid from normal equine tarsal joints were investigated. Tarsal synovial fluid was pale yellow, clear, free of flocculent material, and did not clot. Volume varied in direct proportion to individual tarsal joint size. Relative viscosity was related to volume, polymerization and quantity of hyaluronic acid, and protein concentration. Mucinous precipitate quality (hyaluronic acid polymerization) was uniformly high. Results of certain analyses of serum were compared with those of tarsal synovial fluid. Tarsal synovial fluid protein concentration was low in conjunction with a high A:G ratio. Serum: synovial fluid sugar ratio was 1.24:1. Serum ALP, ACP, LDH, GOT, and GPT activity levels were higher than their corresponding levels of activity in tarsal synovial fluid. Serum ALD activity level was slightly lower than its tarsal synovial fluid counterpart. Total erythrocyte counts ranged markedly, while total leukocyte counts were uniform and low. Lymphocytes were the predominant synovial fluid cell type.