Hand Tendon Injuries: Causes, Treatments, and Prevention

A close up view of two hands as a person holds one of their fingers due to finger pain.

When you take a close look, your hands are pretty remarkable.

Each human hand features dozens of bones, muscles, nerves, blood vessels, and more, all of which work together seamlessly to help you perform everyday tasks.

The human hand also features nearly two dozen tendons, which play a key role in the function of your hand – but are also a common source of hand injuries.

What are tendons?

Tendons are white, fibrous bands that connect a muscle to a bone and allow joints to move.

The human body features thousands of tendons.

Where are the tendons that move your hand?

There are two sets of tendons that attach to various parts of your hand:

  • The flexor tendons are on the palm side of your hand. Flexor tendons bend the fingers and thumb, allowing you to make a fist and pick up objects.
  • The extensor tendons are on the back of your hand. Extensor tendons straighten the fingers and thumb, allowing the hand to release objects or loosen a grip.

Many of the muscles connected to these tendons start all the way from the elbow!

In total, there are nine flexor tendons and 12 extensor tendons that go into your hand.

How do common hand tendon injuries occur?

You can injure a tendon a number of different ways, including:

  • Handling sharp objects, like knives, box cutters, and sheet metal
  • Using industrial equipment, like table saws, snow blowers, and lawn mowers
  • Falling while holding fragile objects, like glass bottles and ceramic bowls
  • Jamming or forceful pulling, including jamming your finger playing basketball or getting your finger stuck in a rope
  • Sustaining direct trauma, like throwing a punch or falling into a door

What are the symptoms of a hand tendon injury?

Hand tendon injuries can present several different ways, depending on the type and severity of the injury.

Common symptoms of a hand tendon injury include:

  • Inability to fully bend or straighten a finger or thumb
  • Pain with movement
  • Swelling
  • Drooping of the finger

What are some common diagnoses you might hear for a tendon injury?

  • Mallet finger, where the tip of the finger droops and can’t be straightened due to a stretched or torn tendon.
  • Jersey finger, which is an injury to a flexor tendon commonly seen in football, rugby, and other contact sports.
  • Boutonniere deformity, which results in a bent fingertip and the inability to straighten the middle joint of the finger.
  • Flexor or extensor tendon lacerations, which are caused by sharp objects cutting through the skin and into the tendon.

How are tendon injuries treated?

Sometimes, torn tendons can heal after a period of immobilization.

This may be achieved via a cast or a custom-made splint to keep the joint in place. The custom splint is made by an occupational or physical therapist.

Tendons that are completely cut typically require surgery.

A hand surgeon will determine the best course of treatment. 

What happens after hand tendon surgery?  

Your surgeon may prescribe occupational or physical therapy for rehabilitation of the repaired tendon. 

The therapist will be someone who specializes in the treatment of the hand, wrist, and elbow.

You will be fitted with a custom splint to protect the repair for approximately 6 weeks.

During that period, only controlled range of motion is allowed and exercises are progressed each week based on the surgical protocol; this means normal use of the hand is greatly restricted.

Each injury is unique, and therefore each rehabilitation process will be different.

Your therapist will guide you through the appropriate precautions.

What are possible complications?

As with any surgery, there’s the potential for complications after hand tendon surgery, including:

  • Damage to the repair if precautions are not properly followed
  • Infection
  • Limited motion due to scar tissue adhesion

How do I prevent hand tendon injuries?

Many people who sustain hand tendon injuries would consider them to be a complete accident – but while there are some truly unpreventable injuries, in many cases, hand injuries occur due to carelessness or unsafe practices.

Always take the proper precautions when handling sharp objects and heavy machinery.

In addition, keep the following tips in mind:

  • Take extra care when using saws and other cutting machinery – check once, twice, three times that your hands are clear of the blade and as protected as possible.
  • Do not stab that avocado pit with a knife – use a spoon!
  • Do not stick your hand in the snow blower or lawn mower, even if the power is off.
  • Do not carry six beer bottles and walk any kind of distance – tripping could have serious consequences.
  • Do not use a butter knife to separate frozen pork chops. Believe it or not, butter knives are sharper than you think.
  • Punching a glass door is a bad idea – please find different ways to channel that anger!


If you suspect a hand tendon injury, please call your doctor right away – injuries that are treated within the first seven to ten days have the most potential for good outcomes.

Peggy Leung, OTR/L, CHT, CLT is an occupational therapist and certified hand therapist at South Shore Health.

Learn more about Occupational Therapy, Hand Therapy, and meet our Hand Therapy Team.