Carpal tunnel syndrome occurs when the median nerve, which runs from the forearm into the palm of the hand, becomes compressed or squeezed at the wrist. The median nerve controls sensations to the palm side of the thumb and fingers (except the little finger), as well as impulses to some small muscles in the hand that allow the fingers and thumb to move. The carpal tunnel – a narrow, rigid passageway of ligament and bones at the base of the hand – houses the median nerve and tendons. Thickening from irritated tendons or other swelling narrows the tunnel and can cause the median nerve to be compressed. The result may be pain, weakness, or numbness in the hand and wrist, radiating up the arm.

This condition is caused when tendons on the thumb side of the wrist are swollen or irritated. The irritation causes the lining (synovium) around the tendon to swell, which changes the shape of the compartment. This makes it difficult for the tendons to move as they should. Thickening of the tendons can cause pain and tenderness along the thumb side of the wrist. This is particularly noticeable when forming a fist, grasping or gripping things, or when turning the wrist.

In trigger finger, also known as stenosing tenosynovitis, one of your fingers or your thumb gets stuck in a bent position and then straightens with a snap – like a trigger being pulled and released. If severe enough, the finger may become locked in a bent position. Trigger finger limits finger movement. When you try to straighten your finger, it will lock or catch before popping out straight.

Trigger finger can be painful and cause stiffness and tenderness, but often it’s more annoying than limiting.

The cause of trigger finger is a narrowing of the sheath that surrounds the tendon in the affected finger (flexor tendon). Tendons are fibrous cords that attach muscle to bone. Each flexor tendon is surrounded by a protective sheath. If the protective sheath becomes inflamed, frequently or for long periods, the space within the tendon sheath can become narrow and constricting. The tendon can’t glide through the sheath easily, at times catching the finger in a bent position before popping straight. With each catch, the tendon itself becomes more irritated and inflamed, worsening the problem. With prolonged inflammation, scarring and thickening (fibrosis) can occur and nodules can form, making the passage of the tendon through the tunnel more difficult.

A sprain is a stretch and/or tear of a ligament, the fibrous band of connective tissue that joins the end of one bone to another. Ligaments stabilize and support the body’s joints. A sprain is caused by direct or indirect trauma (a fall, a blow to the body, etc.) that knocks a joint out of position, and overstretches, and in severe cases, ruptures the supporting ligaments. Typically this injury occurs when an individual lands on an outstretched arm, slides into a base, jumps up and lands on the side of the foot, or runs on an uneven surface.
A strain is an injury of the muscle and/or tendon. Tendons are fibrous cords of tissue that attach muscles to bone. Chronic strains are the result of overuse (prolonged, repetitive movement) of muscles and tendons. Inadequate rest breaks during intensive training precipitates a strain. Acute strains are caused by a direct blow to the body, overstretching, or excessive muscle contraction. In most cases the mechanism of injury resulting in a sprain or a strain may be the same, it’s just a matter of which tissues are damaged in the injury. A wrist sprain is a common injury. There are many ligaments in the wrist that can be stretched or torn, resulting in a sprain. This occurs when the wrist is bent forcefully, such as falling onto an outstretched hand. Wrist strains can be common injuries as well, especially in racket sports and other activities that involve repetitive movement or overstretching of the wrist and forearm. Wrist sprains can range from mild to severe. They are graded, depending on the degree of injury to the ligaments.

• Grade 1. These mild sprains occur when the ligaments are stretched, but not torn.
• Grade 2. These moderate sprains occur when the ligaments are partially torn.Grade 2 sprains may involve some loss of function.
• Grade 3. These severe sprains occur when the ligament is completely torn. These are significant injuries that require medical or surgical care. As the ligament tears away from the bone, it may also take a small chip of bone with it, called an avulsion fracture.