Atlas navigation
From whole to part.
Human anatomy starts with four regions: Arm, Leg, Trunk, and Head & neck. Follow each available branch into smaller regions and individual structures.
Arm opens the whole upper limb, from shoulder to fingertips. Leg, Trunk, and Head & neck are planned and do not yet open regional studies. Head and Neck are subcategories of one shared region. Body systems are a separate way to browse, not a level inside the regional hierarchy. Group headings such as Bones organize links; only underlined names open pages. Individual structure pages retain one canonical regional breadcrumb path.