one's own legs, especially as a means of moving from one
place to another. From the
phrase to go by Shank's mare (or pony): get somewhere on one's own feet, to
walk. The
origin is not known, but it has been stated that it refers to
King Edward I (1239–1307), nicknamed "Long Shanks," because whenever he rode a pony his long legs reached to the
ground. "Shank" is the part of the leg between the knee and the ankle.
—PDC 2 Approved Glossary