sinous blades are more cruel ?

[drdavid]

A clean cut is more difficult to heal, because there are less "ragged edges". The ragged edges from a duller blade actully help the clotting process because the platelets have a better surface to cling to and close the wound as the blood flows out.

I doubt that a surgeon with a sharp scalpel would agree with you on this t_c. A ragged edge tears more as you say but the greater the surface area of damage the greater the blood loss from muscle tissue and the more chance of a partial cut through an artery. Arterial blood loss is really the most dangerous and arteries have coiled smooth muscle around their walls which contracts in an attempt to shut off the artery when it is severed. If you nick the side of an artery however this effect is not apparent and they continue bleeding.

That said a sharp item will generally cut/puncture more deeply than a blunt one, so is more likely to hit something vital.
DrD