The tide mark is a zone at the base of a layer of cartilage where it meets the bone.
The 'tide mark' can only really be appreciated under the microscope.
Under the microscope
If cartilage is stained, and cut into thin slices, and then examined under the microscope, one can see a calcified area of cartilage on the deeper aspect, anchoring the cartilage to the bone. This region looks different from the rest of the cartilage and the line demarcating it is called the tide mark.
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