Muscle and tendon injuries are often obvious because of local pain and swelling. Initially the injury may be underestimated as patients’ are often reluctant to move local joints when they are sore from injury.
Joint movement should return within days if the muscle/tendon is intact.
Extensor tendons are just under the skin. They lie next to the bone on the back of the hands and fingers and straighten the wrist, fingers and thumb. They can be injured by a minor cut or jamming a finger, which may cause the thin tendons to rip from their attachment to bone. If not treated, it may be hard to straighten one or more joints.
The muscles that bend (flex) the fingers are called flexor muscles. These flexor muscles move the fingers through cord-like extensions called tendons, which connect the muscles to bone. The flexor muscles start at the elbow and forearm regions, turn into tendons just past the middle of the forearm, and attach to the bones of the fingers. In the finger, the tendons pass through tunnels that keep them close to the bones, which helps them work better.
Deep cuts can injure the tendons and nearby nerves and blood vessels. An injury that looks simple on the outside can be much more complex on the inside.