Per Riek & Carson 2000 Forearm Right

M. Extensor Carpi Radialis Longus

Extensor Carpi Radialis Longus (ECRL R)

The M. Extensor Carpi Radialis Longus (Extensor Carpi Radialis Longus) is a muscle of the forearm region. It is responsible for wrist dorsiflexion and radial abduction. This muscle is not covered by the official SENIAM catalogue — placement is based on established clinical literature. This page documents the exact electrode position, anatomical attachments and a standardized test movement based on Hermens et al. (2000).

Function

Wrist dorsiflexion and radial abduction

Opposite side: ECRL L

Electrode position on the 3D model: M. Extensor Carpi Radialis Longus (muscle highlighted, sensor in place)

Preview — open the 3D viewer to rotate the model and check neighbouring muscles. View in 3D Viewer

Electrode Placement (SENIAM)

30% on line from lateral epicondyle to Proc. styloideus radii

Orientation: Parallel to the radius

Source: Riek & Carson 2000 ↗

Riek S, Carson RG. A new technique for the selective recording of extensor carpi radialis longus and brevis EMG. J Electromyogr Kinesiol. 2000;10(4):249-57.

Methodological background of the source

Riek & Carson (2000) developed a technique for recording the extensor carpi radialis longus separately from the immediately adjacent brevis. Both muscles lie close together — the position shown here follows that selective recording and is deliberately chosen so that the longus portion dominates.

Recording notes per Criswell 2011, site „Extensor Carpi Radialis (Longus and Brevis)“, p. 325

Placement type: Quasi-specific site Neighbouring muscles contribute noticeably to the signal — allow for crosstalk.
Signal check: Wrist extension and radial deviation.
Crosstalk from: brachioradialis · extensor digitorum

Based on SENIAM recommendations (Hermens et al. 2000). Not an official SENIAM product. See all references → · How electrodes are placed (guide) · Glossary

Go deeper Specific, Quasi-Specific, General — The Three Types of Surface EMG Placement → Can I Measure This Muscle With Surface EMG? →

All 47 muscle protocols as a PDF — free

Print-ready for the lab or clinic: 75 pages of protocols (SENIAM + peer-reviewed), plus the SENIAM table, a placement checklist and a sensor comparison sheet as A4 sheets.

Anatomy

Origin Lateral supracondylar ridge of the humerus Insertion Base of the 2nd metacarpal (dorsal)

Test Movement

Fist closure with wrist dorsiflexion and radial abduction against resistance

This muscle has no SENIAM-standardized electrode position. Placement should be based on anatomical knowledge.

MVC reference test (Konrad 2005)

Position: Seated or kneeling in front of a bench with the forearm resting on a stable support.
Fixation: Forearm fully supported; wrist free to work against the resistance.
Resistance: Manual resistance, a barbell or a cable/belt against the wrist or hand.
Control exercise: Use the latissimus dorsi and pectoralis major tests as control exercises.

Konrad treats the forearm flexors and extensors as one group; wrist flexion for the flexors, wrist extension for the extensors.

Konrad P. The ABC of EMG. Noraxon; 2005, p. 31. Konrad describes this test at group level; it applies to all muscles of the group. · Why and how to normalise to MVC

Measure M. Extensor Carpi Radialis Longus activity live

The electrode is placed — what next? easyEMG visualises muscle activity in real time, with SENIAM-compliant placement guidance, up to 4 channels at once and biofeedback training right afterwards.

In therapy, this muscle is usually about tone regulation and consciously relaxing below a threshold.

EMG biofeedback in therapy → What is EMG biofeedback?

Frequently Asked Questions

Where do I place the EMG electrode on the M. Extensor Carpi Radialis Longus?

30% on line from lateral epicondyle to Proc. styloideus radii. Orientation: Parallel to the radius. Not covered by SENIAM — placement per Riek & Carson 2000.

Which test movement activates the M. Extensor Carpi Radialis Longus?

Fist closure with wrist dorsiflexion and radial abduction against resistance. It serves as a signal check before recording: with correct electrode placement the EMG amplitude rises clearly during this movement.

Is the M. Extensor Carpi Radialis Longus a SENIAM-recommended muscle?

No. The M. Extensor Carpi Radialis Longus is not included in the official SENIAM catalogue. The electrode position documented here follows the established protocol per Riek & Carson 2000.