Muscles/Forearm

Forearm

extensor pollicis brevis

ek-STEN-sor POL-ih-sis BREV-iss

The extensor pollicis brevis sits in the forearm and extends the thumb at its base (metacarpophalangeal joint). It powers thumb opposition and pinch grips vital for weightlifting and climbing. For fitness, it's key in maintaining thumb stability during heavy pulls.

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Common Pain & Injury

Pain at the thumb base or wrist snuffbox, aggravated by pinching or gripping. De Quervain's tenosynovitis often involves it. See a doctor if swelling or crepitus occurs with motion.

Anatomy & Function

Origin

Posterior surface of the radius (lateral forearm bone) and interosseous membrane.

Insertion

Base of the proximal phalanx of the thumb.

Actions

Extension of the metacarpophalangeal joint of the thumb (thumb lift at base)
Abduction of the thumb (thumb spread)

Innervation

Posterior interosseous nerve (C7-C8).

Muscle Relationships

Antagonists

Flexor pollicis brevis

Synergists

Abductor pollicis longusExtensor pollicis longus

Trigger Points

Trigger points over the radial styloid refer pain to the thumb base and wrist.

Stretches

1Thumb extensor stretch

2Finkelstein stretch

Common Conditions

De Quervain's tenosynovitisExtensor pollicis brevis tendinopathy

Anatomical Parts

Left extensor pollicis brevisRight extensor pollicis brevis

FAQ

Extensor pollicis brevis pain?

Common in De Quervain's, causing thumb/wrist pain from repetitive thumb use.

What does extensor pollicis brevis do?

Extends the thumb's base joint for grip strength and precision.

Finkelstein test for?

Tests EPB and APL tendons for De Quervain's inflammation.

Exercises for extensor pollicis brevis

20

Bottoms-Up Clean From The Hang Position position 1

Bottoms-Up Clean From The Hang Position position 2

Bottoms-Up Clean From The Hang Position

intermediate·kettlebells

Cable Wrist Curl position 1

Cable Wrist Curl position 2

Cable Wrist Curl

beginner·cable

Dumbbell Lying Pronation position 1

Dumbbell Lying Pronation position 2

Dumbbell Lying Pronation

intermediate·dumbbell

Dumbbell Lying Supination position 1

Dumbbell Lying Supination position 2

Dumbbell Lying Supination

intermediate·dumbbell

Farmer's Walk position 1

Farmer's Walk position 2

Farmer's Walk

intermediate·other

Finger Curls position 1

Finger Curls position 2

Finger Curls

beginner·barbell

Kneeling Forearm Stretch position 1

Kneeling Forearm Stretch position 2

Kneeling Forearm Stretch

Palms-Down Dumbbell Wrist Curl Over A Bench position 1

Palms-Down Dumbbell Wrist Curl Over A Bench position 2

Palms-Down Dumbbell Wrist Curl Over A Bench

beginner·dumbbell

Palms-Down Wrist Curl Over A Bench position 1

Palms-Down Wrist Curl Over A Bench position 2

Palms-Down Wrist Curl Over A Bench

beginner·barbell

Palms-Up Barbell Wrist Curl Over A Bench position 1

Palms-Up Barbell Wrist Curl Over A Bench position 2

Palms-Up Barbell Wrist Curl Over A Bench

beginner·barbell

Palms-Up Dumbbell Wrist Curl Over A Bench position 1

Palms-Up Dumbbell Wrist Curl Over A Bench position 2

Palms-Up Dumbbell Wrist Curl Over A Bench

beginner·dumbbell

Plate Pinch position 1

Plate Pinch position 2

Plate Pinch

intermediate·other

Rickshaw Carry position 1

Rickshaw Carry position 2

Rickshaw Carry

intermediate·other

Seated Dumbbell Palms-Down Wrist Curl position 1

Seated Dumbbell Palms-Down Wrist Curl position 2

Seated Dumbbell Palms-Down Wrist Curl

beginner·dumbbell

Seated Dumbbell Palms-Up Wrist Curl position 1

Seated Dumbbell Palms-Up Wrist Curl position 2

Seated Dumbbell Palms-Up Wrist Curl

beginner·dumbbell

Seated One-Arm Dumbbell Palms-Down Wrist Curl position 1

Seated One-Arm Dumbbell Palms-Down Wrist Curl position 2

Seated One-Arm Dumbbell Palms-Down Wrist Curl

intermediate·dumbbell

Seated One-Arm Dumbbell Palms-Up Wrist Curl position 1

Seated One-Arm Dumbbell Palms-Up Wrist Curl position 2

Seated One-Arm Dumbbell Palms-Up Wrist Curl

beginner·dumbbell

Seated Palm-Up Barbell Wrist Curl position 1

Seated Palm-Up Barbell Wrist Curl position 2

Seated Palm-Up Barbell Wrist Curl

beginner·barbell

Seated Palms-Down Barbell Wrist Curl position 1

Seated Palms-Down Barbell Wrist Curl position 2

Seated Palms-Down Barbell Wrist Curl

beginner·barbell

Seated Two-Arm Palms-Up Low-Pulley Wrist Curl position 1

Seated Two-Arm Palms-Up Low-Pulley Wrist Curl position 2

Seated Two-Arm Palms-Up Low-Pulley Wrist Curl

beginner·cable

Also Works extensor pollicis brevis

10

Alternate Hammer Curl position 1

Alternate Hammer Curl position 2

Alternate Hammer Curl

beginner·dumbbell

Alternate Incline Dumbbell Curl position 1

Alternate Incline Dumbbell Curl position 2

Alternate Incline Dumbbell Curl

beginner·dumbbell

Alternating Hang Clean position 1

Alternating Hang Clean position 2

Alternating Hang Clean

intermediate·kettlebells

Atlas Stone Trainer position 1

Atlas Stone Trainer position 2

Atlas Stone Trainer

intermediate·other

Atlas Stones position 1

Atlas Stones position 2

Atlas Stones

Axle Deadlift position 1

Axle Deadlift position 2

Axle Deadlift

intermediate·other

Backward Drag position 1

Backward Drag position 2

Backward Drag

beginner·other

Band Assisted Pull-Up position 1

Band Assisted Pull-Up position 2

Band Assisted Pull-Up

beginner·other

Barbell Curl position 1

Barbell Curl position 2

Barbell Curl

beginner·barbell

Barbell Deadlift position 1

Barbell Deadlift position 2

Barbell Deadlift

intermediate·barbell

Related Forearm Muscles

abductor pollicis longus

This forearm muscle runs to the thumb base, abducting and extending it for radial deviation. Vital for wrist stability in lifts like deadlifts. Forearm specialists train it for grip resilience.

Tiny elbow extensor at back upper forearm, stabilizes during pressing and gripping. Aids triceps in extensions. Powerlifters note its elbow lockout role.

brachioradialis

The brachioradialis is the thick forearm muscle on the radial (thumb) side, visible in hammer curls. It flexes the elbow in neutral grip, stabilizing during pulls and carries. Builds Popeye forearms for grip strength.

extensor carpi radialis brevis

The ECRB is a forearm extensor on the radial side, extending and abducting the wrist. Mid-forearm location builds wrist stability for racquets and grips.

extensor carpi radialis longus

The ECRL is the longer radial wrist extensor, more proximal in forearm for powerful extension and abduction. Stabilizes in heavy pulls.

extensor carpi ulnaris

The ECU is the ulnar (pinky) wrist extensor in posterior forearm, balancing extension with deviation. Key for stability in sports.

extensor digiti minimi

The EDM is a thin forearm muscle specifically extending the pinky finger at knuckles and wrist. Lies ulnar to EDM, aids fine grip control.

extensor digitorum

The extensor digitorum is the central posterior forearm muscle, extending fingers 2-5 at knuckles and wrist. Fan-like tendons create dorsal hand ridges for grip extension.

Forearm Pain Guide

Common causes and relief

Activities & Sports

See which activities use extensor pollicis brevis