Kinesiology

Makenzie Sharp

Pledged:

Kinesiology

December 2, 2013

The elbow and the radioulnar joints are used often and consist of many boney landmarks, muscles, and ligaments that allow them to do the movements that we need on an everyday basis. The majority of our upper extremity movements involve the elbow and the radioulnar joints. Both the elbow and the radioulnar joints are usually grouped together and while the elbow joint movements can be clearly distinguished from those of the radioulnar joints, the radioulnar joint movements may be distinguished from those of the wrist.

The bones of the elbow and radioulnar joints consist of the ulna which is much larger proximally than the radius while the radius is much larger distally than the ulna. The ulna and the radius also serve as distal attachments for muscles that flex and extend while the scapula and the humerus serve as proximal attachments for these same muscles. The distal attachments of the radioulnar joint muscles are located on the radius. The medial condyloid ridge, olecranon process, coronoid process, and radial tuberosity are important bony landmarks for these muscles.

The elbow joint is classified as a hinge-type joint that only allows flexion and extension. The motions of the elbow primarily involve movement between the articular surfaces of the humerus and the ulna, specifically humeral trochlear fitting into ulna trochlear notch. The radial head has a relatively small amount of contact with the capitulum of the humerus. As the elbow reaches full extension, the olecranon process is received by the olecranon fossa, which increases joint stability when fully extended. As the elbow flexes twenty degrees or more, the bony stability is unlocked which allows more side to side movement. The stability of the elbow in flexion is more dependent on the collateral ligaments, such as the lateral or radial collateral ligament and especially the medial or ulnar collateral ligament. The ulnar collateral ligament...