Tendons connect muscle to bone, producing movement of the joints in the body. Tendons in the arm can be strained with overuse or injury, significantly impacting function. Muscles that bend the wrist, thumb and fingers forward into flexion and backward into extension are frequently strained. To fully rest the tendons connected to these bones, a splint is worn to temporarily immobilize the wrist.
Muscles that bend the fingers and wrist are collectively called flexors. Tendons attach to the bones in the fingers and wrist from several muscles in the forearm. These muscles come together at the elbow and connect to one tendon, the common flexor tendon. This tendon crosses the elbow joint, attaching to the medial epicondyle, the pointy bone on the inside of the elbow.
The extensor muscles straighten the fingers and bend the wrist backward. Tendons attach to the fingers and wrist from multiple muscles in the forearm. The extensor muscles come together and form one tendon at the elbow, the common extensor tendon. This tendon attaches to the lateral epicondyle, the pointy bone on the outside of the elbow.
Two tendons that move the thumb are frequently strained. The tendons run from bones in the thumb to muscles in the forearm, attaching to bone on the pinky side of the forearm. One helps move the thumb into extension, the "hitchhiking" position. The other moves the thumb into abduction, which describes movement to the side, as in grasping a cup or glass. This condition of irritation of the tendons at the base of the thumb is called De Quervain's tenosynovitis.
De Quervain's Tenosynovitis
Caused by inflammation of the thumb abductor and extensor tendons, pain occurs along the thumb side of the wrist and lower forearm. A thumb spica splint is used to immobilize the wrist and thumb to rest these tendons. This splint is similar to a wrist cock-up splint. It covers approximately half the length of the forearm and is secured with fastening straps. This splint, however, has an additional piece covering the length of the thumb. An aluminum bar within this part of the splint prevents the thumb from moving.
A thumb spica splint is worn during the day to reduce pain with daily tasks. Function is affected with this splint because the thumb cannot be used. As with other conditions, this splint may be worn for several months until symptoms resolve.
Tennis elbow, or lateral epicondylitis, is a condition caused by microtearing of the common extensor tendon. Pain and swelling occur at the outside of the elbow, on and around the lateral epicondyle. The only way to fully rest the injured area is to immobilize the wrist. A wrist cock-up splint covers approximately half of the length of the forearm and ends in the palm. A hole cutout allows thumb movement. This splint often has an aluminum bar along the front of the forearm and is secured by fastening straps. The splint is worn during the day to prevent wrist movement with daily tasks, and may be used for several months. Although wrist immobilization is a common treatment for tennis elbow, according a 2001 review published in the "British Journal of General Practice," it has not been proven effective for reducing tennis elbow symptoms.
Golfer's elbow, also called medial epicondylitis, is caused by microtearing of the common flexor tendon on the inside of the elbow. Pain and swelling develop at or around the medial epicondyle and daily tasks become difficult.
Golfer's elbow is immobilized with the same splint used to treat tennis elbow, the wrist cock-up splint, worn during the day to prevent movement during daily tasks. As with tennis elbow, this splint may be used for several months until symptoms resolve.