Suture

The prompt

Build a suturing trainer. The pad is not always flat skin, and the cut is not always a straight slit. Each case is a tissue: forearm skin, the skin of the back, a cheek, fascia, bowel, a small artery, or a tendon. The wound may be straight, curved, jagged, wavy, or oblique. The pad is under tension, so the cut gapes until it is closed.

Before I place a stitch I choose a suture and a needle. Sutures differ in three ways: whether the body absorbs them, whether they are one strand or a braid, and whether they are natural or synthetic. Absorbable suture belongs on fascia and bowel. Non-absorbable suture belongs on skin, vessel, and tendon. A single strand slides and harbours fewer bacteria, but it is springy and a soft knot slips. A braid handles well and locks a knot, but it drags, so a shallow bite holds less. Natural suture inflames the tissue more than a synthetic one. Needles are round-bodied, cutting, or reverse cutting. A round needle pushes soft tissue aside and belongs in bowel and vessel. A cutting needle slices skin, fascia, and tendon. Reverse cutting is the kinder cutting needle on a skin edge.

I place a stitch by choosing where the needle enters one lip and leaves the other, how deep it goes, and how tight I tie it. On a curved or jagged wound the bite should cross the cut where it actually runs. The tissue should draw together when I tie, and spring open again if I cut a stitch out. A bite that is too shallow, too close to the edge, made with the wrong needle, or yanked too tight should tear out. I can change suture and needle between stitches.

Score the closure when I say I am finished. The lips should meet along the wound. The stitches should sit at a sensible depth and width, stay roughly even along the length of the cut, cross the local wound, and not be so tight the tissue blanches. The suture and the needle should suit that tissue. A neat pattern that leaves the wound open should not score well. The back and the tendon are under more tension: too few stitches, or the wrong material, and they tear.

Show the pad from above with the thread in the suture's colour, and a side view of the needle passing through the named layers, with the needle point drawn. Show which suture and needle are selected, and a short line saying what this tissue wants. This is a teaching model, not a medical device.

# AI : shared Action contract — the page posts {"move": "..."}; keep this shape.
from pydantic import BaseModel


class Action(BaseModel):
    move: str