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Extensor Pollicis Brevis

Region

Origin & Insertion

['Origin: Posterior radius and interosseous membrane', 'Insertion: Base of proximal phalanx of thumb']

Synergistic Muscles

['APL', 'EPL']

Joints

['Wrist', 'Thumb MCP']

Primary Actions

['Extends thumb at MCP', 'Assists in wrist abduction']

Nerve & Spinal Segment

Radial nerve (posterior interosseous branch)

Brachial plexus; C7–C8

Interesting

Part of the anatomical snuffbox. [Moore’s]

Reversal of Action

Raise palm toward fixed thumb

Common Dysfunctions

Thumb pain, reduced extension power, De Quervain’s syndrome

How to Stretch

Flex thumb across palm.

Trigger Points

How to Strengthen

Thumb extension against resistance.

Concentric Action

Extend thumb at MCP joint

Applications:

Helps isolate thumb control in grip retraining

Eccentric Action

Control flexion of MCP

Isotonic Action

Thumb extensions with band or manual resistance

Related Conditions

['De Quervain’s', 'Thumb tendonitis']

Isometric Action

Hold thumb extended

Exercise Ideas

['Thumb lifts', 'Band thumb raise', 'Rubber band abduction']

Related Blogs

Images

Videos

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