Elbow Complex

Elbow Complex

1. Radio-humeral Joint

   • Contributes to all motions at the elbow and resists excessive valgus at the elbow
     • With excessive valgus the concave surface of the radial head contacts the convex surface of the trochlea
       • Radial head fracture primary MOI = FOOSH

2. Radio-ulnar joint

   • Proximal radio-ulnar joint + Distal radio-ulnar joint
     • Function together for successful supination and pronation

3. Ulno-humeral Joint

   • Primary articulation contributing to elbow flexion
     • Two fossa at humerus articulating with the ulna
       • Humerus Fossa
         • 1. Olecranon fossa 2. Coronoid fossa
       • Ulna Processes
         • 1. Olecranon fossa 2. Coronoid fossa
       • Between 50-90 degrees of elbow flexion these articulations are not in contact within either fossa (loose pack)
         • Ulno-humeral loose pack 70 degrees. Radio-humeral joint 70 degrees of flexion + 30 degrees supination.
     • 2 Condyles
       • Capitulum (lateral)
       • Trochlea (medial)
         • Extends further distally = Carrying angle (slight valgus in full extension)
           • Female normal angle 13-16 degrees
           • Male norm angle 11-14 degrees
     • Structural Observation
       • Anterior view
         • Full Extension + Full Supination = cubital valgus / Full Extension + Full Pronation = no cubital valgus
       • Posterior View
         • Full extension the Medial/Lateral epicondyle + olecranon process are in straight line
         • Full flexion = Medial/Lateral epicondyle + olecranon process = equilateral triangle