The arm has three long bones: one in the upper arm, two in the forearm. In anatomical position (palm forward), the radius is on the thumb side and the ulna on the pinky side. Tap each.
Humerus
The armhumerus · radius · ulna
The bones
💡 Memory: the ulna is on the same side as your pinky (“u” for the underside/pinky); the radius rotates (it's on the thumb side and lets you turn your palm).
📷 Reference image
A real labeled figure to compare with the interactive above.
Bones of the Upper Limb — OpenStax, CC BY 3.0 (via Wikimedia Commons)
