anatomy and physiology mcqs

Question #415

Extensor carpi radialis longus

Extensor carpi radialis arises from the lateral supracondylar ridge of the humerus with only a few fibres arising from the common extensor origin. It passes beneath the extensor retinaculum in the same compartment as extensor carpi radialis brevis before inserting into the base of the second metacarpal. Extensor carpi radialis brevis inserts into the base of the third metacarpal.

It is innervated by the radial nerve C6,C7.

It extends and abducts the wrist and is a weak extensor of the elbow.

Since the long finger flexors are at a mechanical disadvantage when the wrist is flexed, extensor carpi radialis longus and brevis both act in synergy with the finger flexors to hold the wrist in a neutral position.

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