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MuscleForearm & handsuperficialBeyond Cert IVDraft

Extensor carpi radialis brevisMusculus extensor carpi radialis brevis

Wrist extensor lying just under its longer partner, running from the lateral epicondyle to the middle finger metacarpal and lifting the back of the hand.

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LatinMusculus extensor carpi radialis brevis
Origin
  • Lateral epicondyle of the humerus (common extensor tendon)
  • Radial collateral ligament of the elbow
  • Intermuscular septa between it and the neighbouring muscles
Insertion
  • Back (dorsal) surface of the base of the 3rd metacarpal
Action
  • Extends the wrist
  • Slightly abducts the wrist (radial deviation)
NerveDeep branch of the radial nerve (C6–C7)
GroupWrist extensors
NameLatin: the 'short straightener of the wrist (carpus) on the radius side'.

Palpation

  1. Client supine or seated with the forearm palm down and supported.
  2. Find extensor carpi radialis longus just below and in front of the lateral epicondyle, then move down the forearm.
  3. ECRB lies alongside and slightly behind ECRL, and becomes more superficial towards the middle of the forearm.
  4. Ask the client to make a fist and lift the back of the hand straight up against resistance; at the wrist, feel its tendon in line with the middle finger's metacarpal.

Landmarks: Lateral epicondyle of humerus

Extensor carpi radialis brevis is the central member of the Wrist extensors. Wikipedia describes its tendon as the main one that the others merge into at the common extensor tendon on the Lateral epicondyle of humerus. Clients who have been told they have “tennis elbow” (lateral elbow pain) commonly report tenderness at this spot, just below and in front of the epicondyle.

Careful Cross-fibre friction or Stripping of the muscle belly is often used here, with a wrist-flexion stretch afterwards. Keep pressure on the tendon itself within the client’s comfort, and refer on if pain is sharp or getting worse.

Sources disagree on the nerve roots. Gray’s (1918) gives C6–C7 (used here), Kenhub gives C5–C6, and Wikipedia gives no level. Wikipedia’s infobox names the deep branch of the radial nerve, while its text says only “a branch of the radial nerve”.

Techniques

  • Petrissage — Kneading strokes that compress, lift and squeeze the muscle away from the bone, working the tissue between the hands.
  • Stripping — A slow, deep, narrow glide along the length of a single muscle with the thumb, knuckle or elbow, pausing over tight bands on the way.
  • Cross-fibre friction — Deep, specific friction applied back and forth across the direction of a tendon, ligament or muscle's fibres, with the fingers and skin moving together as one.
  • Trigger point pressure release — Sustained thumb or finger pressure on a tender spot within a taut band of muscle, held until the client reports the discomfort easing, then slowly released.
  • Passive stretching — The therapist gently moves a relaxed limb to lengthen a muscle to a point of mild stretch and holds it there, with no effort from the client.

Works with

  • Extensor carpi radialis longus — Outer forearm muscle running from above the lateral epicondyle to the index finger metacarpal, extending the wrist and tilting it towards the thumb.
  • Extensor carpi ulnaris — Long muscle on the back of the forearm next to the ulna that extends the wrist and tilts it towards the little finger.
  • Extensor digitorum — Muscle in the middle of the back of the forearm whose four tendons straighten the fingers and help extend the wrist.

Opposes

  • Flexor carpi ulnaris — Superficial muscle along the inner (little-finger) border of the forearm that bends the wrist and tilts it towards the little finger.

Same group

  • Extensor carpi radialis longus — Outer forearm muscle running from above the lateral epicondyle to the index finger metacarpal, extending the wrist and tilting it towards the thumb.
  • Extensor carpi ulnaris — Long muscle on the back of the forearm next to the ulna that extends the wrist and tilts it towards the little finger.
  • Extensor digitorum — Muscle in the middle of the back of the forearm whose four tendons straighten the fingers and help extend the wrist.

Sources

  1. Wikipedia: Extensor carpi radialis brevis muscle
  2. Wikipedia: Common extensor tendon
  3. Gray's Anatomy of the Human Body (1918), Myology 7e: The Muscles and Fasciae of the Forearm (Public domain. Used for origin detail and nerve roots (sixth and seventh cervical).)
  4. Kenhub: Extensor carpi radialis brevis muscle (Gives roots C5–C6, which differs from Gray's.)