Extensor Carpi Radialis Longus Detail

musculus extensor carpi radialis longus detail

ECRL has the most proximal radial nerve supply of any forearm extensor, arising directly from the radial nerve before it divides into superficial and deep (PIN) branches. This makes ECRL the most proximal muscle to test in radial nerve injuries.

Nerve: Radial nerve (C6, C7) — branch arising above… Blood Supply: Radial recurrent artery Region: Forearm

Anatomical Data

Origin, Insertion & Supply

Origin	Lateral supracondylar ridge of the humerus — proximal end, above the lateral epicondyle
Insertion	Base of the second metacarpal — dorsal surface
Nerve Supply	Radial nerve (C6, C7) — branch arising above the lateral epicondyle
Blood Supply	Radial recurrent artery

Biomechanics

Function & Actions

Actions	Extends the wrist; Radially deviates the wrist — the primary wrist radial deviator; Assists elbow flexion via the lateral supracondylar ridge origin

Clinical Relevance

Clinical Notes

ECRL preservation with absent PIN function localises the radial nerve lesion to the PIN (posterior to the lateral epicondyle). ECRL is transferred in tendon transfer surgery to restore finger flexion (ECRL to FDP in high median + ulnar palsy). In de Quervain surgery, ECRL travels in the second extensor compartment alongside ECRB.

Palpation

Palpated on the lateral forearm dorsum during resisted wrist extension with radial deviation.

Pathology

Common Injuries & Conditions

ECRL Preservation in PIN Palsy

Intact ECRL function in posterior interosseous nerve palsy distinguishing PIN entrapment from high radial nerve palsy — ECRL is spared because its nerve branch arises proximal to the PIN origin.