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Elbow Anatomy and Biomechanics Mimi Renaudin, DPT University of Mississippi Medical Center Slide 2 Objectives Describe the anatomy and joint articulations at the elbow Discuss the static and dynamic constraints acting at the elbow Identify the neurovascular contributions within the elbow joint Slide 3 Elbow Snap Shot Trochoginglymoid joint 2 Degrees of freedom Flexion/Extension and forearm rotation Humerus Radius Ulna Slide 4 Anatomy Overview Slide 5 Slide 6 Joint Articulations Humeroulnar Proximal Radioulnar Humeroradial Slide 7 Anterior Muscular Component 9 muscles cross the anterior aspect of the joint Only 3 have primary action on the elbow Radioulnar joint - rotation Remaining 4 muscles arise from common flexor tendon on medial epicondyle Slide 8 Elbow Flexors Slide 9 Radioulnar Motion Supinator, pronator teres with assistance from pronator quadratus distally Slide 10 Anterior Musculature Final 4 muscles attach on medial epicondyle Primary actions occur at the wrist and digits PL FCR FCU FDS Slide 11 Posterior Muscular Component Elbow extensors: triceps, anconeus Triceps: 3 heads Long: crosses GH and elbow Medial/Lateral: only cross elbow Anconeus Common extensor tendon Slide 12 Elbow Extensors Slide 13 Lateral Epicondyle Attachments Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor carpi ulnaris Extensor digiti minimi Slide 14 Capsuloligamentous Complex Medial collateral ligament Lateral collateral ligament Slide 15 Medial Collateral Ligament Resists valgus stress Limits extension Taut throughout arch of motion Anterior fibers most taut in extension Posterior bundle is taut in flexion Transverse fibers provide valgus stability and help with joint approximation Slide 16 Vascular Contribution Slide 17 Normal Elbow Motion Normal ROM: Elbow 0-145 Pronation: 80 Supination: 85 Functional ROM: Elbow 30-130 Pronation: 50 Supination: 50 Slide 18 Carrying Angle Formed by valgus tilt of the axis of rotation (humeral articulation) and the valgus orientation of the ulnar shaft in reference to the olecranon Slide 19 References 1.DeLee, Drez. DeLee and Drezs Orthopaedic Sports Medicine. 3 rd ed. 2009. 2. Levangie PK, Norkin CC. Joint Structure & Function. 4 th ed. 2005. 273-295. 3. Moore KL, Dalley AF, Agur AM. Clinically Oriented Anatomy. 6 th ed. 2010. 734-762. Slide 20 Questions