Figs. 6-21 and 6-23. On the left is an anterior perspective of the right radius and ulna, showing anatomical landmarks. Cross-sections of the midportions of the shafts show the arrangement of surfaces and borders. Capital letters indicate surfaces, and small letters indicate borders. The figures to the right show muscular and ligamentous attachments to the right radius and ulna. About midway on the shaft of the radius is a rough area for the insertion of the pronator teres, below which the shaft is covered by the tendons of the brachioradialis and the extensor carpi radialis longus and brevis. The interosseous membrane gives origin in part to the flexor pollicis longus and flexor digitorum profundus. Click for high resolution image.