Anatomy of the hand
The hand is composed of many different bones, muscles, and ligaments that allow for a large amount of movement and dexterity. There are three major types of bones in the hand itself, including the following:
- phalanges the 14 bones that are found in the fingers of each hand and also in the toes of each foot. Each finger has three phalanges (the distal, middle, and proximal); the thumb only has two.
- metacarpal bones the five bones that compose the middle part of the hand.
- carpal bones the eight bones that create the wrist. The carpal bones are connected to two bones of the arm, the ulnar bone and the radius bone.
Numerous muscles, ligaments, and sheaths can be found within the hand. The muscles are the structures that can contract, allowing movement of the bones in the hand. The ligaments are fibrous tissues that help bind together the joints in the hand. The sheaths are tubular structures that surround part of the fingers.
Two major problems associated with tendons include tendonitis and tenosynovitis. Tendonitis, inflammation of a tendon (the tough cords of tissue that connect muscles to bones) can affect any tendon, but is most commonly seen in the wrist and fingers. When the tendons become irritated, swelling, pain, and discomfort will occur.
Tenosynovitis is the inflammation of the lining of the tendon sheaths which enclose the tendons. The tendon sheath is usually the site which becomes inflamed, but both the sheath and the tendon can become inflamed simultaneously. The cause of tenosynovitis is often unknown, but usually strain, overuse, injury, or excessive exercise may be implicated. Tendonitis may also be related to disease (i.e., diabetes or rheumatoid arthritis).
Common tendon disorders include the following:
- lateral epicondylitis (commonly known as tennis elbow) – a condition characterized by pain in the back side of the elbow and forearm, along the thumb side when the arm is alongside the body with the thumb turned away. The pain is caused by damage to the tendons that bend the wrist backward away from the palm.
- medial epicondylitis (commonly known as golfer’s or baseball elbow) – a condition characterized by pain from the elbow to the wrist on the palm side of the forearm. The pain is caused by damage to the tendons that bend the wrist toward the palm.
- rotator cuff tendonitis – a shoulder disorder characterized by the inflammation of the shoulder capsule and related tendons.
- DeQuervain’s tenosynovitis – the most common type of tenosynovitis disorder characterized by the tendon sheath swelling in the tendons of the thumb.
- trigger finger/trigger thumb – a tenosynovitis condition in which the tendon sheath becomes inflamed and thickened, thus preventing the smooth extension or flexion of the finger/thumb. The finger/thumb may lock or “trigger” suddenly.
Treatment for most tendon problems may include:
- activity modification
- splinting or immobilization
- steroid injections
- nonsteroidal anti-inflammatory medications