Elbow Injury Specialists Wheeling WV
Orthopedic Surgery, Sports Medicine
St Clairsville, OH
Physical Medicine and Rehabilitation
St Clairsville, OH
Glen Dale, WV
The elbow is made up of three bones, which are connected by muscles, ligaments and tendons. The humerus is the large upper arm bone. The ulna and radius are the two bones in the forearm. Looking at the forearm with the palm of the hand facing up, the ulna is located on the inner (medial) aspect of the forearm. The radius is located on the outer (lateral) aspect of the forearm. Projecting from the end of the humerus are the medial and lateral epicondyles. The epicondyles are the boney attachment sites for many of the forearm muscles.
The elbow joint is actually three separate joints; the ulnohumeral joint, the radiohumeral joint and the superior radioulnar joint. These three joints are enclosed by a loose "bag" called the joint capsule. Movement between the ulna and the humerus occurs at the ulnohumeral joint. Movement between the radius and the humerus occurs at the radiohumeral joint and movement between the radius and the ulna occurs at the superior radioulnar joint.
Ligaments are like strong ropes that connect bones and provide stability to joints. In the elbow there are four main ligaments. On medial aspect of the elbow is the ulnar collateral ligament that connects the ulna to the humerus. On lateral aspect of the elbow is the radial collateral ligament that connects the radius to the humerus. The other two ligaments are the annular ligament and the quadrate ligament. They connect the radius to the ulna.
Articular cartilage is a smooth shiny material that covers the ends of the bones in the elbow. There is articular cartilage anywhere that two bony surfaces come into contact with each other. In the elbow, articular cartilage covers the ends of the humerus, radius and ulna. Articular cartilage allows the elbow bones to move easily as the elbow bends (flexes), straightens (extends), rotates the palm up (supinates), and rotates the palm down (pronates).
The strong biceps, brachialis and brachioradialis muscles flex the elbow. The triceps muscle extends the elbow. Other muscles that move the hand at the wrist originate at the elbow. These muscles attach via tendons to the medial and lateral epicondyles. The forearm muscles that originate on the medial epicondyle help to flex the wrist and hand. The forearm mu...
The elbow joint is actually three separate joints; the ulnohumeral joint, the radiohumeral joint and the superior radioulnar joint. All three joints are enclosed by a single joint capsule. Movement between the ulna and the humerus occurs at the ulnohumeral joint. Movement between the radius and the humerus occurs at the radiohumeral joint and movement between the radius and the ulna occurs at the superior radioulnar joint.
The ulnohumeral and radiohumeral joints are modified hinge joints. The biceps, brachialis, and brachioradialis muscles bend (flex) these two joints. The triceps muscles on the back of the arm straighten (extend) these two joints. Normal elbow flexion varies between 135 degrees to 155 degrees. The superior radioulnar joint is a pivot joint. This joint allows supination and pronation of the forearm and wrist to occur. Supination is rotation of the forearm so that the palm is turned up. Pronation is rotation of the forearm so that the palm is turned down. The biceps and supinator muscles supinate the elbow. The pronator quadratus, pronator teres and flexor carpi radialis muscles pronate the elbow.
When the elbow is fully extended and supinated, the forearm is angled slightly away from the long axis of the humerus. This angle is called the "carrying angle". In men this angle ranges between 10 to 15 degrees and in women this angle ranges between 15 to 20 degrees. Muscle weakness or ligament injury can lead to abnormal biomechanics of the elbow that can result in abnormal forces in the elbow. Over time these abnormal forces can cause the articular cartilage of the elbow to w...