Cartilage Thickness. Measurement of cartilage thickness of (A) rat, (B) rabbit and (C) goat. Mean cartilage thickness was derived from a minimum five readings in each slide. Representative slides were obtained from the posterolateral condyle of left distal femur. Surface area is calculated in 500 μm (five boxes) in length and full thickness in depth. (Safranin O staining; magnification rat and rabbit 10×, goat 4× objective lens).