Where bone sits close under the skin

Most of the pain people report from body gua sha is not caused by pressing too hard. It is caused by pressing a normal amount over a place where there is nothing between the stone and a bone.

The fix is a two-minute habit: before working a region, find its bony landmarks with your fingertips and decide where the stroke will begin and end. This post is the map.

Why bone changes everything

The tissue is the buffer, and the buffer is what varies. Over a shoulder slope there are centimetres of muscle to spread the load. Over the front of the shin there is skin. The same force through the same stone produces a dull working sensation in the first case and a bright, specific pain in the second.

Pressure over bone achieves nothing anyway. The technique works by dragging load through muscle and fascia. Where there is no muscle, there is nothing for the stroke to act on, so the discomfort buys you nothing at all.

Ridges are worse than flat bone. A broad flat surface with thin cover, like part of the shoulder blade, is uncomfortable. A sharp edge, like the front of the shin or the crest of the spine, concentrates the load into a line and is where skin actually breaks.

The map, top to bottom

The spine’s crest. The line of bumps down the middle of the back, feelable from the base of the skull to the pelvis. Never work over it; work parallel to it, a centimetre or two to each side.

The shoulder blade’s ridge. A pronounced bar across the upper part of the blade. The muscle over the flat part of the blade takes pressure reasonably; the ridge does not.

The point of the shoulder. The hard knob at the very top, where the collarbone meets the shoulder blade’s outer end.

The collarbone. Bare bone along its whole length, front of the body, with skin over it and nothing else.

Ribs at the sides and the floating ribs low down. Not a no-go so much as a much-reduced-pressure zone. Follow the direction of the ribs rather than crossing them, and lighten considerably.

The pelvic rim. The bony edge you can feel at the top of the hip and around the back at the bottom of the low back.

The elbow, all of it. The point at the back, the knob on either side — the inner one with a nerve crossing it — and the soft hollow at the front where vessels run close to the surface.

The bony ridge on the little-finger side of the forearm. Traceable from elbow to wrist, essentially uncovered.

The wrist. Tendons, vessels and nerves in a narrow space. Not a bony landmark exactly, but on the same list for the same reason.

The bony point on the outside of the hip. The prominence the outer thigh’s fibrous band passes over.

The kneecap and the bony areas either side of the knee, plus the hollow behind the knee, which is soft and full of vessels and nerves.

The knob on the outside of the leg just below the knee, where a nerve passes close to the surface.

The front edge of the shin. The clearest example on the body, and the one people most often disregard.

The ankle bones and the top of the foot. Bone and tendon with a thin covering.

WHAT'S NORMAL — the pre-session check

  · Trace the region's edges with your fingertips
                          → find bone before the stone does
  · Decide where each stroke starts and stops
                          → both ends on soft tissue
  · Dull, deep, spread sensation
                          → you are on tissue
  · Bright, sharp, narrow, specific pain
                          → you are on bone. Move.
  · A ridge or edge you can feel through skin
                          → work parallel to it, never across
  · Grinding or clicking sensation under the stone
                          → stop. Wrong place.

How to work around a landmark rather than over it

Parallel, not across. Long bones and ridges are best treated as walls to run alongside. The spine, the ribs and the ulna all work this way.

Stop two centimetres short. Ending a stroke slightly early costs nothing. Running a stroke onto a bony edge at full load is where the trouble is, because the moment of contact is also the moment your lean is fully committed.

Treat joints as boundaries between regions. Above and below a joint are two separate regions with a gap in between, not one continuous run. This is why the arm and the shoulder slope are worked separately.

Adjust the angle rather than the force when a stroke turns sharp near a landmark. Laying the stone flatter spreads the contact, which is usually the correction that is actually needed.

What the tradition says

Traditional instruction is generally careful about bony areas, and traditional practice tends to concentrate on the fleshy regions of the back, shoulders and limbs. The specific landmarks are described in the tradition’s own vocabulary rather than in the terms used here.

That is a description of the practice, not a claim about mechanism. Nothing about which regions to avoid depends on the traditional framework being correct — it follows from where the bones are, which anyone can check.

Cautions

Bone is only one of the reasons to skip an area. Do not scrape over broken, irritated or sunburnt skin, moles, lesions or rashes, recent surgery or injury, infected or actively inflamed areas, varicose veins, or anything you cannot account for.

Do not do this at all with a bleeding disorder or on anticoagulant medication. Reduced sensation anywhere means you cannot feel when you have found bone, which makes the whole technique a poor idea in that area — ask a clinician. If you are pregnant, have a skin condition, or are unsure, ask first.

If a stroke over a bony area has broken skin, treat it as a wound and leave the area alone until it has healed fully. Pain that persists after a session, rather than fading over a day or two, belongs in the same category as any unexplained pain: worth asking about.