The Radius is lateral, the Ulna is medial.
Ulna (pl. ulnae):
Olecranon Process: Named due to its articulation with the olecranon fossa of the humerus
Ulnar Tuberosity: Obvious tuberosity in the proximal half of the bone
Coronoid Process: Named due to its projection into the coronoid fossa of the humerus when flexing the forearm at the elbow
Trochlear Notch: Articulates with the trochlea of the humerus
Radial Notch: Receives the head of the Radius
Head: At the DISTAL end
Styloid Process: Jutts out of the head
Radius (pl. radii):
Head: Articulates with the capitulum of the humerus. Is at the proximal end.
Radial Tuberosity: Medial and visible from the posterior view
Ulnar Notch: Articulates with the head of the ulna and is therefore located at the distal end
Styloid Process: Emerges from the distal end