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Elbow Anatomy and Biomechanics . Mimi Renaudin, DPT University of Mississippi Medical Center. 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.
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Elbow Anatomy and Biomechanics Mimi Renaudin, DPT University of Mississippi Medical Center
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
Elbow Snap Shot • Trochoginglymoid joint • 2 Degrees of freedom • Flexion/Extension and forearm rotation • Humerus • Radius • Ulna
Joint Articulations Humeroulnar Humeroradial Proximal Radioulnar
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
Radioulnar Motion • Supinator, pronatorteres with assistance from pronatorquadratus distally
Anterior Musculature • Final 4 muscles attach on medial epicondyle • Primary actions occur at the wrist and digits • PL • FCR • FCU • FDS
Posterior Muscular Component • Elbow extensors: triceps, anconeus • Triceps: 3 heads • Long: crosses GH and elbow • Medial/Lateral: only cross elbow • Anconeus • Common extensor tendon
Lateral Epicondyle Attachments • Extensor carpiradialislongus • Extensor carpiradialisbrevis • Extensor digitorum • Extensor carpiulnaris • Extensor digitiminimi
Capsuloligamentous Complex • Medial collateral ligament • Lateral collateral ligament
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
Normal Elbow Motion • Normal ROM: • Elbow 0-145° • Pronation: 80° • Supination: 85° • Functional ROM: • Elbow 30-130° • Pronation: 50° • Supination: 50°
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
References • DeLee, Drez. DeLee and Drez’sOrthopaedic Sports Medicine. 3rd ed. 2009. 2. Levangie PK, Norkin CC. Joint Structure & Function. 4th ed. 2005. 273-295. 3. Moore KL, Dalley AF, Agur AM. Clinically Oriented Anatomy. 6th ed. 2010. 734-762.