Distally, at the wrist, the radius predominates, but both ulna and radius have a styloid process for wrist articulation stability. Colles' fracture is a common fracture of the radius at the distal end. Most common carpal fracture is to the scaphoid , e.g., fall on outstretched hands. The scaphoid b. is in the floor of the anatomical snuffbox , as defined by the tendons of extensor pollicis longus vs. abductor pollicis longus and extensor pollicis brevis mm . Concern about avascular necrosis in proximal fragment after scaphoid fracture.
Metacarpals make up the palm of the hand, with their heads forming the knuckles.
The interphalangeal joints are hinge joints. The elbow is a hinge joint formed by humerus, radius, and ulna. These are combined in one joint capsule, with the support of collateral ligaments, as well as an anular ligament to hold the radial head against a corresponding ulnar notch. Extensor muscles originate from the lateral epicondyle and repeated use, as with a backhand stroke with a tennis racket, may cause a strain on the periosteum and tendinous muscle attachments. Those muscles that flex the elbow joint are members of the brachial group, and are innervated by the musculocutaneous nerve , e.g., biceps brachii muscle and brachialis muscle .