means The bony front edge of the lower leg, running from knee to ankle, with almost no padding to soften a blow.

from From Old English 'scinu,' meaning the shin or shank, with relatives across the old Germanic tongues — Dutch 'scheen' and German 'Schiene' (which now also means a splint or rail). The deeper sense seems to point at something thin and flat, a strip of bone laid bare just under the skin — which is precisely why the coffee table always wins.