Final answer:
The ulna is located medial to the radius in the anatomical position, meaning it is found closer to the midline of the body relative to the radius.
Step-by-step explanation:
In the anatomical position, the ulna is located on the medial side of the forearm relative to the radius. The ulna is parallel to the radius and is found closer to the midline of the body when standing in the standard anatomical position. This means the ulna lies medial to the radius, which is on the lateral side of the forearm. The proximal end of the ulna articulates with the humerus at the elbow, and its distal end partially articulates with the wrist, though not directly with the carpal bones.
The interosseous membrane connects the ulna and radius along their shafts, providing a site for muscle attachment and allowing for the transfer of forces across the forearm. The ulna and radius also form two joints together—the proximal and distal radioulnar joints, which enable the forearm to rotate during pronation and supination movements.