Biomechanics Of The Elbow Range of Motion

The elbow complex controls the position of the hand and wrist complex in space and in proximity to the upper body. This control is accomplished primarily with two joints within the elbow complex that have one degree of freedom: flexion and extension at the humeroradial and humeroulnar joints and pronation and supination at the proximal radioulnar joint. Normal range of motion for elbow flexion is 0° to 145°12; for pronation, 70° to 80°; and for supination, 80° to 85°. Functional range of motion is less than the maximum range because most daily activities (e.g., eating, opening a door, reading, and rising from a chair) are performed within an arc of 100° of flexion (from 30° to 130°) and between 50° of pronation and 50° of supination.2

In a study of the passive motion, Morrey and Chao determined that the elbow is not a true hinge joint.3 They determined that a locus of the instant centers of rotation is present. As Werner and An indicated, further work also has demonstrated that the orientation of the three-dimensional center of rotation varies from person to person.4 However, Morrey and Chao concluded that, for each individual, the deviation is minimal, and irregularity can be attributed to experimental design.3 Therefore, it is assumed that the ulnohumeral joint moves as a uniaxial articulation, except for the extreme ranges of flexion and extension.5

The axis of rotation for flexion forms a line from the inferior aspect of the medial epicondyle through the center of the lateral epicondyle.3 This line bisects the longi tudinal axis of the humerus, but not the longitudinal axis of the forearm. The longitudinal axis of the humerus and the longitudinal axis of the forearm create a valgus angle (i.e., the carrying angle) because of the configuration of the articulating surfaces. Morrey and Chao3 found that the carrying angle changes with elbow flexion. London, however, found that the carrying angle remained con-stant.6 An et al.7 concluded that the magnitude of the carrying angle depends on its definition. They also indicated that the change in carrying angle that occurs during flexion and extension has little clinical significance.

Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

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