Why the map crosses

The point is named for the pain it answers, not the limb it is given on

Pressure on one or both legs, between the groin and the ankle, relieves pains above the navel. Pressure on the arms or forearms, up to the wrists, relieves pains between the navel and the perineum. Pressure on the left arm or leg relieves pains on the right of the navel; pressure on the right arm or leg relieves pains on the left. Left Right

Now lay the front chart beside it. The Gal pain point lies right of the midline, under the right rib margin — answered from the left thigh. Spl lies left — the right thigh. Liv lies right of the navel — the left limbs; Mu left of it — the right. Const lies in the left upper quadrant — the right thigh; Dys in the right — the left. WD is a midline point below the navel, and so is not given on a thigh at all, but on both forearms.

The code names the pain point. The limb is chosen by the rule.

Once you hold that, the atlas becomes a thing you could almost reconstruct. Liv and Mu take an arm and a thigh together, because their pain points sit at the level of the navel itself, on the boundary between what the legs answer and what the arms answer. Gas 'I' — the small intestine, coiled around the navel — is given on the calves, further down the same limb. WD, lowest of all, is furthest out of all: the forearms, elbow to wrist.

And within a single limb the ring rule decides which station: the nearer the navel, the further down the limb. That is why the Gal entry says pain at the number one place is relieved near the waist on the left thigh, while pain at the number three place is relieved near the knee of the same thigh.