Origin and history of leg

Middle English bon, from Old English ban "bone, tusk, hard animal tissue forming the substance of the skeleton; one of the parts which make up the skeleton," from Proto-Germanic *bainan (source also of Old Frisian and Old Saxon ben, Old Norse bein, Danish ben, German Bein). Absent in Gothic, with no cognates outside Germanic (the common PIE root is *ost-); the Norse, Dutch, and German cognates also mean "shank of the leg," and this is the main meaning in Modern German, but English seems never to have had this sense.

To work (one's) fingers to the bone is from 1809. To have a bone to pick (1560s) is an image of a dog struggling to crack or gnaw a bone (to pick a bone "strip a bone by picking or gnawing" is attested from late 15c.); to be a bone of contention (1560s) is of two dogs fighting over a bone; the images seem to have become somewhat merged. Also compare bones.

Bone-china, which is mixed with bone-dust, is so called by 1854. Bone-shaker (1874) was an old name for the early type of bicycle, before rubber tires.

"leg of a human or animal," especially "the part of the leg from the knewe to the ankle," Old English sceanca "leg, shank, shinbone," specifically, the part of the leg from the knee to the ankle, from Proto-Germanic *skunkia-, perhaps literally "that which bends," from PIE root *skeng- "crooked" (source also of Old Norse skakkr "wry, distorted," Greek skazein "to limp").

From late 15c. as "straight part of a nail or pin." As "part of an instrument, tool, etc., which connects the acting part with the handle," from 1680s. The slang sense of "latter part or end of anything" is by 1828.

Jocular shank's mare "one's own legs as a means of transportation" is attested from 1774 (as shanks-naig).

Germanic cognates include Middle Low German schenke, German schenkel "shank, leg."