S&i Radio Ulnar Jnt

Superior & Inferior Radioulnar Joints Superior Radioulnar joint •

•

Formed by ulnar radial notch,annular ligament, capitulum, and head of radius Annular ligament encircles the rim of head

Inferior Radioulnar joint • Formed by ulnar notch of radius,articular disk and head of ulna • Articular disk is referred to as triangular fibrocartilage (TFC)

Ligaments: 2. Annular ligament 3. Quadrate ligament 4. Oblique cord 5. Dorsal and palmar radioulnar ligament 6. Interosseous membrane

 

Radioulnar articulation: • Proximal and Distal radioulnar joints are mechanically linked • Motion at one joint is always linked by motion at another joint • The distal radioulnar joint is functionally linked to the wrist, hence compressive loads are transmitted from the hand through the joint to the radius and ulna

Axis Of Motion: • The axis of radioulnar joint is a long axis extending from the center of the radial head to the center of the ulnar head • In supination both bones lie parallel to each other where as in pronation radius crosses over ulna

During pronation, the following five motions take place: c. Radius crosses over the ulna at the superior radioulnar joint d. Head of the radius spins within the osteoligamentous exposure formed by the radial notch and annular ligament e. Radial head spins on the capitulum f. Concave ulnar notch slides around the ulnar head at the inferior radioulnar joint g. The articular disk twists at the apex and sweeps below the ulnar head

•

•

•

•

There is minimal contact between the articulating surfaces when the forearm is in Supination/pronation Optimal contact occurs when the forearm is in midprone There is negligible motion at the proximal ulna during pronation The distal ulnar head moves distally and dorsally in Pronation and proximally and medially in Supination

RANGE OF MOTION: • Total range of motion is 150° & is always assessed with elbow in 90° flexion • This position helps to check the rotations at the radioulnar joint and avoids rotations at the glenohumeral joint  Factors checking forearm pronation 5. Bone approximation 6. Dorsal radioulnar ligament 7. Posterior fibers of MCL of the elbow  Factors checking forearm supination 9. Palmar radioulanr ligament 10. Quadrate ligament 11. Interosseous membrane

Stability: Proximal Radioulnar joint: Ligaments: • Annular & quadrate ligament • Oblique cord • Interosseous membrane Muscles: • Passive tension in biceps • Pronator teres

Distal Radioulnar joint: Ligaments: • Interosseous membrane • Dorsal radioulnar ligament • Palmar radioulnar ligament • Triangular fibrocartilage • Joint capsule Muscles: • Pronator quadratus • Pronator teres • Extensor carpi ulnaris • Anconeus

Muscles: Pronator teres,Pronator quadratus, Biceps Brachii & Supinator FUNCTIONAL ACTIVITIES (ADL) : • Most activities of daily living require a combination of motion at the elbow and radioulnar joints • A total of 100° of elbow flexion with 100° of supination/pronation is comfortable for simple tasks • A range of 30-130° of elbow flexion with 50° of pronation & 55° of supination to allow the normal functioning of the hand

Compression Injury:

Distraction Injury:

Valgus/Varus Injury:

Cubital Tunnel syndrome: