Bone with a radial notch

ULNA

This forearm bone runs parallel to the radius and forms the pointed part of your elbow when you bend your arm.

The clue refers to the ulna, one of the two long bones in your forearm. It mentions the "radial notch" because that’s a key feature of the ulna—a small indentation where it connects with the radius, the other forearm bone. This anatomical detail helps distinguish the ulna from the radius, making it the clear answer.