• Origin

Lateral epicondyle of the humerus (via the common extensor tendon).

• Insertion

Extensor expansions of digits 2–5 (dorsal surfaces of the middle and distal phalanges).

• Agonist(s)

- Extensor indicis (for index finger extension),

- Extensor digiti minimi (for little finger extension),

- Lumbricals and interossei (assist in finger extension at the interphalangeal joints).

• Antagonist(s)

- Flexor digitorum superficialis,

- Flexor digitorum profundus,

- Flexor digiti minimi brevis (for little finger).

• Function

Extends the metacarpophalangeal joints (MCP) of digits 2–5.
Assists in extension of the proximal and distal interphalangeal joints.
Assists in wrist extension.
Helps stabilize the hand during fine motor tasks.

TRIGGER POINT(S)

• Location

Trigger points are often found in the muscle belly in the proximal third of the dorsal forearm, just distal and lateral to the lateral epicondyle.

Can also develop further down the muscle belly along the dorsal forearm.

• Pain Referral Pattern

Pain may radiate down the dorsal surface of the forearm into the back of the hand and fingers (especially digits 3–5).

Referral pain may mimic deep aching in the hand, often mistaken for arthritic or nerve-related symptoms.

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Potential Causes

• Repetitive finger or wrist extension (e.g., typing, playing musical instruments).

• Gripping or lifting with extended fingers.

• Prolonged use of tools with poor wrist posture.

• Overuse from activities requiring constant finger movement.

• Chronic tension or compensation from weak intrinsic hand muscles.

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Prevention Tips

• Use ergonomic setups for typing and manual tasks.

• Perform regular stretching of the wrist and finger extensors.

• Alternate tasks to reduce repetitive motion strain.

• Strengthen intrinsic hand muscles to reduce compensatory overuse.

• Take breaks during prolonged hand or forearm activity.