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Extensor carpi radialis longus



Extensor carpi radialis longus - posterior view
Extensor carpi radialis longus - anterior view
Extensor carpi radialis longus - lateral view

General information

  • This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page
  • Is a part of the lower arms radial muscle group


  • Superficial


  • Lateral supracondylar ridge of humerus (distal 1/3)
  • Lateral septum intermusculare


  • 2. metacarpal (posterior)

Main function

  • Wrist
    • Extension
    • Radial deviation

Secondary function

  • Elbow
    • Flexion
    • Pronation

Nerve innervation

  • Segmental
    • C5-C7
  • Peripheral
    • Radial nerve

Arterial supply

  • Brachial artery
  • Radial artery


  • Patient position
    • Sitting or supine
  • Place your hand just posteriorly to the brachioradialis
  • Ask the patient to make a fist while he/she holds the wrist in a neutral position
  • Feel for the contraction in the muscle

Strength test

  • Patient position
    • Sitting
  • Ask the patient to hold the arm in 30° flexion in the elbow while the elbow is pronated
  • Give resistance towards the dorsal side of the hand of the patient at about the 2-3 metacarpal in a flexion and ulnar deviation direction, so that the patient is giving force towards extension and radial deviation
  • The patient maintains the position of the hand while you give resistance