The lower head of the |humerus| features an arrangement of prominences and depressions which facilitate its articulation with the |radius| and |ulna|. At the lower surface is a rounded area, made of the capitulum and trochlea of the |humerus|. The olecranon of the |ulna| can be seen at the back of the elbow, fitting into the depression between these two features. Each side of the head of the |humerus| features a protrusion, called an ~epicondyle~. When the arm is held beside the body, with the palm facing up, the lateral ~epicondyle~ is on the side of the |humerus| which is away from the body, while the |medial epicondyle| is next to the torso. Between the ends of the |radius| and |ulna| is a small notch (the radial notch) where the two bones join at the end.