Flexor and extensor tendon injuries

Flexor and extensor tendon injuries happen when the tendons that let your fingers or thumb bend and straighten become cut, torn or damaged. These injuries can make it difficult to move your hand normally and often require prompt attention to heal well. With proper treatment, most people regain function and return to daily activities.

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A medical illustration of two arms with descriptions of muscles and tendons.

Anatomy of the hand

Tendons are strong, cord-like tissues that connect muscles to bones. In your hand, flexor tendons run along the palm side of your fingers and allow you to bend them, while extensor tendons run along the back of your hand and fingers and allow you to straighten them. These tendons work together so your fingers can grip, pinch and release with control.

Because flexor and extensor tendons sit close to the surface of the hand, they're especially vulnerable to cuts, punctures and other injuries. Damage to either type of tendon can limit your ability to move the affected finger or thumb normally.

Overview

Symptoms

Symptoms of a flexor or extensor tendon injury can vary depending on the severity and location of the damage. Common signs include:

Inability to bend or straighten the affected finger or thumb
Pain near a cut, wound or injury site
Swelling in the finger or hand
Weakness when trying to grip or pinch
A finger that rests in an unusual position compared to the others
Numbness or tingling if nerves are also affected

If left untreated, tendon injuries can lead to long-term stiffness or permanent loss of movement, so early evaluation is important.

Causes

Flexor and extensor tendon injuries often result from trauma to the hand. Common causes include:

Cuts or lacerations from knives, glass or machinery
Deep puncture wounds
Sports injuries, especially from jamming a finger
Forceful bending or straightening of a finger against resistance
Animal or human bites
Crush injuries

In some cases, tendons can also be damaged by underlying conditions, such as rheumatoid arthritis, that weaken the tissue over time.

Risk factors

Certain factors may increase your risk of a flexor or extensor tendon injury, though having one or more of these does not mean an injury will occur:

Jobs or hobbies involving sharp tools or machinery
Participation in contact sports or activities with a high risk of jamming fingers
Conditions like rheumatoid arthritis that can weaken tendons
Previous hand injuries

Talking with your care team about your risk factors can help guide safe activity choices and preventive steps.

Diagnosis

Diagnosing a flexor or extensor tendon injury starts with a review of how the injury occurred and a physical exam to check hand movement, strength and sensation. Your doctor will examine the injured area closely and may recommend imaging to assess the extent of the damage and rule out other injuries, such as fractures.

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We offer leading-edge treatments for most hand and wrist conditions, treating many with medications, bracing, injections and therapy.

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Our board-certified specialists are here to help you heal. They can often diagnose the problem in one visit and get you started with a personalized treatment plan. We offer a wide variety of treatment options.