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Hand and Finger Tendon Injuries (Flexor and Extensor)
Understanding tendon injuries that affect bending or straightening a finger or thumb, and why prompt assessment matters.
What is Hand and Finger Tendon Injuries (Flexor and Extensor)?
Tendons are the strong, cord-like structures that connect muscles to bone and allow the fingers and thumb to move. Flexor tendons, on the palm side of the hand, bend the fingers, while extensor tendons, on the back of the hand, straighten them. A tendon injury is a cut, tear or rupture of one of these tendons, most often from a cut such as broken glass or a knife, or occasionally from a forceful bending or straightening injury without any cut at all.
Hand and Finger Tendon Injuries (Flexor and Extensor) at a glance
What is it?
A cut, tear or rupture of a tendon that bends (flexor) or straightens (extensor) the finger or thumb
Common symptoms
Inability to bend or straighten a finger normally, often with a wound and pain
Who it affects
Anyone who sustains a cut to the hand, or a forceful bending or straightening injury
Is it serious?
Needs timely assessment, as delayed treatment can make repair harder and affect finger function
Treatment options
Surgical repair for most complete injuries, followed by structured hand therapy
First step
Prompt assessment to determine which tendon is involved and whether surgery is needed
Symptoms and how Hand and Finger Tendon Injuries (Flexor and Extensor) presents
The main sign is an inability to bend (for a flexor tendon injury) or straighten (for an extensor tendon injury) part or all of a finger. There is often a wound over the area if the injury was caused by a cut, along with pain, swelling, and sometimes an abnormal resting posture of the finger.
Sometimes there is no pain, and minimal trauma has occurred – this can be the case for a mallet finger injury. Most flexor tendon injuries occur due to a penetrating injury, but the flexor tendon can pull off the ring finger in a condition called jersey finger, or FDP avulsion.
Causes and risk factors for Hand and Finger Tendon Injuries (Flexor and Extensor)
- Cuts from knives, glass or machinery
- Forceful injuries such as jamming a finger during sport
- Work-related injuries
- Deep wounds involving the palm, fingers or back of the hand
How are Hand and Finger Tendon Injuries (Flexor and Extensor) diagnosed?
Diagnosis is based on examining the movement of each tendon individually, since it is possible to injure one tendon while others still work. Any wound is also assessed for associated nerve or blood vessel injury. Ultrasound is occasionally used if the diagnosis is unclear, but it is not 100% sensitive or specific (ie not 100% accurate) in confirming whether a tendon injury has occurred, and sometimes surgical exploration may be the recommended treatment rather than imaging.
Treatment options for Hand and Finger Tendon Injuries (Flexor and Extensor)
Most complete tendon injuries are repaired surgically, usually within days of the injury to give the best chance of a good outcome. An exception to this is a mallet finger injury.
After repair, a structured hand therapy and splinting program is an important part of recovery, and the details are tailored to which tendon was injured and how it was repaired.
Some partial tendon injuries, where the tendon is not completely cut through, may be managed without surgery, depending on how much of the tendon is affected.
When to see a hand surgeon about Hand and Finger Tendon Injuries (Flexor and Extensor)
Any cut to the hand or finger where you cannot fully bend or straighten it, or any sudden loss of finger movement, should be assessed urgently, as tendon injuries are best repaired promptly.
What to expect at your Hand and Finger Tendon Injuries (Flexor and Extensor) appointment
At assessment, Dr Tomlinson or her team will examine your wound and test the movement of each tendon, and arrange surgery promptly if a repair is needed.
Frequently Asked Questions
What is a hand or finger tendon injury?
Tendons are the strong, cord-like structures that connect muscles to bone and allow the fingers and thumb to move. Flexor tendons, on the palm side of the hand, bend the fingers, while extensor tendons, on the back of the hand, straighten them. A tendon injury is a cut, tear or rupture of one of these tendons.
What causes it?
Most tendon injuries are caused by cuts from knives, glass or machinery, forceful injuries such as jamming a finger during sport, work-related injuries, or deep wounds involving the palm, fingers or back of the hand.
What can I do myself?
Any cut to the hand or finger where you cannot fully bend or straighten it, or any sudden loss of finger movement, should be assessed urgently. Keep the wound clean and covered and avoid using the finger while you arrange assessment.
What can a hand therapist do?
After a tendon repair, a structured hand therapy and splinting program is an important part of recovery, tailored to which tendon was injured and how it was repaired.
What can a hand surgeon do?
At assessment, Dr Tomlinson or her team will examine your wound and test the movement of each tendon individually, since it is possible to injure one tendon while others still work. Most complete tendon injuries are repaired surgically, usually promptly after the injury. Some partial tendon injuries may be managed without surgery, depending on how much of the tendon is affected.
What can I expect from treatment?
Most complete injuries are repaired surgically, followed by a structured hand therapy and splinting program tailored to your specific injury and repair.
What happens if it's left untreated?
Tendon injuries need timely assessment, as delayed treatment can make repair harder and affect finger function.
Related conditions and treatments
A cut that injures a tendon can also injure a nearby nerve, so tendon injuries are often assessed alongside nerve injuries and lacerations of the hand. A specific extensor tendon injury at the fingertip is known as mallet finger.