Which bone in the forearm is located closest to the pinky finger?

The ulna is the bone in the forearm that is located closest to the pinky finger. It plays a crucial role in the structure and function of the forearm and wrist. The ulna runs parallel to the radius, with the ulna being positioned on the inner side when the palms are facing forward, which aligns it closely with the pinky finger. This anatomical positioning allows for the ulna to provide stability to the wrist and facilitates various movement ranges of the hand.

The radius, while also a forearm bone, is situated on the opposite side of the ulna and is closer to the thumb, which contrasts with the position of the pinky finger. The clavicle is a bone located in the shoulder region that connects the arm to the body but is not part of the forearm structure. Similarly, the humerus is a bone in the upper arm that articulates with the forearm bones but is not directly involved in the forearm's proximity to the pinky finger. Thus, the ulna’s proximity to the pinky finger makes it the correct answer in this context.