Anatomy is mostly a question about depth — what is under the needle at six millimetres, which nerve a fracture at this level takes with it — and an atlas answers it one static plane at a time. The block below moves the plane instead, and colours the structures by tissue rather than by name, because the rules worth carrying (the bundle travels together, the compartment predicts the nerve) are about types and not about labels.
Move the plane down through the arm. Structures are coloured by tissue type, with the clinical consequence under each.
Four to eight millimetres in, and the plane every cannula is aimed at: the superficial veins run in the fat, above the deep fascia, which is why they roll under the needle and why a line that has gone too deep stops flowing.
You describe the goal in your own words and it asks questions back until the plan is one you would actually follow. These are the shapes that goal usually takes.
Not a fixed syllabus — the plan is built around your goal and cuts what does not serve it. These are the topics it draws from, and whatever you get wrong comes back until it stops coming back.
The mechanics are the same whatever the subject — a slider is a slider whether it is moving a coefficient or a rate of return. What changes is what it is a slider for.
Or see how it works and what it costs.