Everything else in anatomy is built on three foundations, and this category installs all three in order. First you map the body as a set of cooperating organ systems, so every organ you meet later already has a team to belong to. Then you name the skeleton — the frame that every muscle, nerve and joint is described against. Finally you pick up the directional language, the anterior/posterior, proximal/distal, sagittal/coronal vocabulary that lets you say exactly where anything sits. Get these automatic and the rest of medical anatomy stops feeling like a foreign language.
Level up to the major bones by their medical names — femur, clavicle, scapula and the rest.
Finish with the directional terms and body planes anatomists use to describe every location precisely.