The Spanish for “to scratch”, rasgar, comes from the Latin secare, “to cut.”
From the same root, we also get the English Section.
A section, indeed, is just a cut into different parts. And a scratch is really almost a cut as well!
We can see the parallel in mapping the s-ct of section to the s-g of rasgar. Although the -ct- sound didn’t commonly turn into a -g-, we can hear the guttural connection if we sound it out.