The 18th Century prototype for the chainsaw was used as a surgical tool for dissecting limbs and symphysiotomy.
Symphysiotomy is a surgical operation in which cartilage is cut out of the pubis in order to widen the pelvis and allow the baby to pass through.
Scottish doctors John Aitken and James Jeffray invented the prototype around 1783-1785.
This chain hand saw was particularly used for the removal of diseased knees and elbows.
The chain saw was still in use for much of the 19th Century until the Gigli twisted wire saw replaced it.