Tendons are long, rope-like fibrous tissues, which connect forearm muscles to thumb and finger bones. When forearm muscles contract, tendons pull on finger bones, allowing fingers to move. The flexor tendons insert into the thumb and finger bones on the palm-side of the hand. They facilitate flexing or bending of fingers. The extensor tendons insert into the thumb and finger bones on the back-side of the hand. They are responsible for extending or straightening the fingers.
Tendon injuries can occur in the forearm, at the wrist, in the palm, or along the finger. Depending on whether the tendon was partially or fully torn, this type of injury may make it difficult or impossible to bend or straighten one or more joints in a finger. Since tendons are under tension as they connect muscle to the bone (like a rubber band), if a tendon is completely cut, the ends of the tendon will recoil and pull apart. Timely surgical intervention is required to reattach the two separated ends in order for them to heal.
When there is an injury to the tendon, a hand surgeon will evaluate your hand, wrist, and forearm for any nerve and blood vessel injuries. Three major nerves - radial, median, and ulnar - innervate hand and wrist in a specific pattern. If there is an injury to these nerves or their branches, you may experience numbness and tingling in certain parts of fingers, hand or wrist. If blood vessels are damaged and a finger is not receiving proper blood supply, immediate surgery is imperative.