radial collateral ligament of wrist joint radial collateral ligament of wrist joint the radial collateral ligament (external lateral ligament, radial carpal collateral ligament) extends from the tip of the styloid process of the radius and attaches to the radial side of the scaphoid (formerly navicular bone of the hand), immediately adjacent to its proximal articular surface and some fibres extend to the lateral side of the trapezium (greater multangular bone). radial collateral ligament (wrist)ligaments of wrist. anterior view. (radial collateral visible at center left.)detailsfromradial styloid processtolateral scaphoid and trapeziumidentifierslatinligamentum collaterale carpi radialeta98a03.5.11.008ta21801fma40006anatomical terminology it is in relation with the radial artery, which separates the ligament from the tendons of the abductor pollicis longus and extensor pollicis brevis. the radial collateral ligament's role is to limit ulnar deviation at the wrist.