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[Conditions](https://durgical.com/en/conditions/) · [Upper limb](https://durgical.com/en/anatomy/region/upper-limb/)

# Flexor tendon injury

A flexor tendon injury is a cut of the tendons that bend the fingers or thumb, usually from a wound on the palm side of the hand, wrist or forearm.

Updated 2026-10-29

## Structures involved

Tap one to see what it is and open it in 3D.

- [FDP tendons](https://durgical.com/en/anatomy/flexor-digitorum-profundus-tendons/)
- [FDS tendons](https://durgical.com/en/anatomy/flexor-digitorum-superficialis-tendons/)
- [Flexor tendon sheaths](https://durgical.com/en/anatomy/flexor-tendon-synovial-sheaths/)
- [Finger pulleys](https://durgical.com/en/anatomy/flexor-tendon-sheaths-and-pulleys/)
- [FPL](https://durgical.com/en/anatomy/flexor-pollicis-longus/)
- [A1 pulleys](https://durgical.com/en/anatomy/a1-pulleys-of-the-flexor-tendon-sheaths/)
- [Digital nerves](https://durgical.com/en/anatomy/palmar-digital-nerves/)
- [Digital arteries](https://durgical.com/en/anatomy/palmar-digital-arteries/)
- [FDP](https://durgical.com/en/anatomy/flexor-digitorum-profundus/)
- [FDS](https://durgical.com/en/anatomy/flexor-digitorum-superficialis/)

## Why it happens

- [Tissue repair: regeneration or scar; labile, stable and permanent cells](https://durgical.com/en/general-pathology/tissue-repair-regeneration-or-scar-labile-stable-and-permanent-cells/)
- [Connective tissue proper: cells and fibres](https://durgical.com/en/histology/connective-tissue-proper-cells-and-fibres/)

## What it is

Partial or complete division of the tendons that bend the fingers and thumb ([flexor digitorum profundus](https://durgical.com/en/anatomy/flexor-digitorum-profundus/), [flexor digitorum superficialis](https://durgical.com/en/anatomy/flexor-digitorum-superficialis/) and [flexor pollicis longus](https://durgical.com/en/anatomy/flexor-pollicis-longus/)), usually by a cut on the palm side of the hand, wrist or forearm. Treatment and outcome depend on the anatomical zone of the injury.

## Who gets it

Mostly young working-age adults, more often men, after injuries with knives, glass, tools and machinery at home or at work. Closed avulsion of the profundus tendon (jersey finger) occurs in contact sports.

## Causes

- Cuts from knives, glass, metal sheets or tools
- Crush and machinery injuries
- Closed avulsion of the profundus tendon from the distal phalanx when a flexed finger is forced straight (jersey finger, usually the ring finger)
- Attritional rupture in rheumatoid arthritis or over bony prominences

## Risk factors

- Manual work with sharp tools or machinery
- Kitchen and glass injuries
- Contact sports such as football and rugby (closed avulsion)
- Rheumatoid arthritis

## Pathophysiology

In the fingers the two flexor tendons run inside a tight synovial sheath held to the bone by pulleys, of which A2 and A4 prevent bowstringing. Cut tendons retract and do not heal unless their ends are brought together; their nutrition comes from vincula and synovial fluid. Healing scar easily binds tendon to sheath, so tight repairs with early protected movement are needed to keep gliding.

## Classification

- Zone I: distal to the superficialis insertion, profundus tendon only
- Zone II (no man's land): from the distal palmar crease (A1 pulley) to the superficialis insertion, both tendons inside the tight sheath
- Zone III: palm, where the lumbricals arise
- Zone IV: within the [carpal tunnel](https://durgical.com/en/anatomy/carpal-tunnel/)
- Zone V: wrist and forearm, proximal to the carpal tunnel
- Thumb zones T I to T V; jersey finger avulsions are graded by Leddy and Packer

## Symptoms and signs

- Inability to bend one or more finger joints
- Loss of the normal resting flexion cascade: the injured finger lies straighter than its neighbours
- Abnormal tenodesis effect: the finger does not flex when the wrist is passively extended
- Numbness of the side of a finger if the digital nerve is also cut
- Wound on the palm side of the finger, palm or wrist

## Red flags

- Pale or cool finger, suggesting digital artery injury
- Numbness from digital or median or [ulnar nerve](https://durgical.com/en/anatomy/ulnar-nerve/) injury
- Contaminated or bite wound, or signs of flexor sheath infection
- Deep wrist laceration with several tendons, nerves and arteries cut

## Diagnosis

**Clinical**
Profundus test: with the middle joint held straight, the patient cannot bend the end joint. Superficialis test: with the other fingers held straight, the patient cannot bend the middle joint. Sensation and capillary refill of each digit are checked.

**Tests**
Not usually needed; tetanus status is reviewed.

**Imaging**
X-rays look for fractures, bony avulsion and glass or metal fragments; ultrasound or MRI can locate a retracted tendon end or a partial tear.

## Differential diagnosis

- Anterior interosseous or [median nerve](https://durgical.com/en/anatomy/median-nerve/) palsy
- Trigger finger with locking
- Pulley rupture
- Joint stiffness or fracture limiting flexion
- Pain inhibition without tendon injury

## Goal of treatment

Restore continuity of the tendon with a repair strong enough for early protected movement, preserve the key pulleys and regain smooth gliding and full finger motion.

## Treatment

**Acute**
Wound cleaning, closure or dressing, splint with wrist and fingers flexed, tetanus prophylaxis and antibiotics for contaminated wounds, and referral to hand surgery.

**Surgical**
Primary repair, usually within the first days, with multi-strand core sutures and an epitendinous suture, preserving the A2 and A4 pulleys and repairing cut nerves and arteries.

**Surgical**
Jersey finger: re-attachment of the profundus tendon to the distal phalanx, urgent when the tendon has retracted into the palm.

**Rehabilitation**
Hand therapy with a protective splint and early controlled active or passive motion protocols for several weeks, then strengthening.

**Surgical**
Late or failed cases: tenolysis for adhesions, or staged tendon reconstruction with grafts.

## Complications

- Adhesions that limit tendon gliding
- Re-rupture of the repair
- Joint contracture and stiffness
- Bowstringing after pulley damage
- Infection and quadriga effect (limited flexion of neighbouring fingers)

## Prognosis

Outcome depends on the zone, the cleanliness of the wound, the quality of repair and adherence to therapy. Zone II injuries have historically had the most adhesions; modern repair with early motion has improved results, but full motion is not always regained.

## Prevention

- Safe handling of knives, glass and tools
- Machine guards and gloves at work

## Test yourself

Think of the answer, then tap the question to see it.

## Why is flexor tendon zone II called no man's land?

Both flexor tendons run together inside the tight fibro-osseous sheath, where repairs easily form adhesions and historically had poor results.

## How is the flexor digitorum profundus tested in a finger?

The examiner holds the PIP joint straight; inability to flex the DIP joint indicates a cut profundus tendon.

## How is the flexor digitorum superficialis tested in a finger?

The other fingers are held in extension to block the profundus; inability to flex the PIP joint indicates a cut superficialis tendon.

## Which pulleys are most important to preserve to prevent bowstringing?

The A2 and A4 pulleys.

## What is a jersey finger?

Closed avulsion of the profundus tendon from the distal phalanx when a flexed finger is forcibly extended, most often the ring finger.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/flexor-tendon-injury/)

## Related conditions

- [Rheumatoid arthritis of the hand and wrist](https://durgical.com/en/conditions/rheumatoid-arthritis-of-the-hand-and-wrist/)
- [Trigger finger](https://durgical.com/en/conditions/trigger-finger/)
- [Mallet finger](https://durgical.com/en/conditions/mallet-finger/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Flexor Tendon Lacerations](https://www.ncbi.nlm.nih.gov/books/NBK493223/) (StatPearls (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/conditions/flexor-tendon-injury/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/flexor-tendon-injury/