Figure 4.

Examples of microdamage in the parasagittal groove of younger horses. (A) Mild microdamage in Horse 4 showing a cluster of obliquely aligned calcified cartilage microcracks beneath intact hyaline cartilage. Scale bar: 500 μm. (B) Moderate microdamage in Horse 5 showing microcracks associated with lesion formation in the overlying hyaline cartilage (see arrow). Note also the more subtle but similarly aligned cracks in the subchondral bone (see boxed region). Scale bar: 500 μm. (C) Moderate microdamage in Horse 6 showing two distinct recesses in the calcified cartilage closely associated with microdamage (see arrows), as well as small lesions (voids) at the same locations. Scale bar: 300 μm.