above and below the skin
piercing the skin to let the pus out and wounds where the blood stays beneath, and never breaks through the skin
and is the skin a separate part of the animal?
(laws against trapping, inflicting a wound and killing on shabbat. can pierce the skin to drain an abscess . also discussed on this page is the prohibition against making a a wound. defined as causing blood to bruise beneath the skin. also discussed is the prohibition to trap or wound any of the 8 named creeping animals, and whether or not their skin is considered part of their flesh or separate. for english translation of this talmud page, see here)