<P> When the forearm is extended and supinated, the axis of the arm and forearm are not in the same line; the arm forms an obtuse angle with the forearm, known as the carrying angle . During flexion, however, the forearm and the hand tend to approach the middle line of the body, and thus enable the hand to be easily carried to the face . </P> <P> The accurate adaptation of the trochlea of the humerus, with its prominences and depressions, to the trochlear notch of the ulna, prevents any lateral movement . </P> <P> Flexion in the humeroulnar joint is produced by the action of the biceps brachii and brachialis, assisted by the brachioradialis, with a tiny contribution from the muscles arising from the medial epicondyle of the humerus . </P> <P> Extension in the humeroulnar joint is produced by the triceps brachii and anconeus muscle, with a tiny contribution from the muscles arising from the lateral epicondyle of the humerus, such as the extensor digitorum muscle . </P>

Where does the ulna radiate with the humerus