Per Criswell 2011 Forearm Left

M. Extensor Carpi Ulnaris

Extensor Carpi Ulnaris (ECU L)

The M. Extensor Carpi Ulnaris (Extensor Carpi Ulnaris) is a muscle of the forearm region. It is responsible for wrist dorsiflexion and ulnar 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 ulnar abduction

Opposite side: ECU R

Rotate the body, see the electrode position in place — and check the neighbouring muscles right away. View in 3D Viewer

Electrode Placement (SENIAM)

Ulnar (little-finger) side of the forearm, a few cm distal to the elbow; palpate the muscle belly during ulnar deviation of the wrist

Orientation: Parallel to the muscle fibres, 2 cm inter-electrode distance

Source: Criswell 2011

Criswell E. Cram's Introduction to Surface Electromyography. 2nd ed. Jones & Bartlett Learning; 2011. ISBN 978-0-7637-3274-5.

Methodological background of the source

Criswell (2011) — Cram's Introduction to Surface Electromyography, 2nd edition — is the standard textbook for surface EMG electrode placement beyond the SENIAM catalogue. Its atlas section (Part III) describes, for each site, palpation, electrode location with 2 cm spacing parallel to the fibres, a behavioural test and the neighbouring muscles from which crosstalk is to be expected. Cram's classifies the position used here as "quasi-specific" — the muscle cannot be fully separated from its neighbours at the surface. The position is established in practice but less validated than a SENIAM recommendation.

Recording notes per Criswell 2011, site „Extensor Carpi Ulnaris“, p. 324

Placement type: Quasi-specific site Neighbouring muscles contribute noticeably to the signal — allow for crosstalk.
Signal check: Ulnar deviation of the wrist.

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 epicondyle of the humerus, dorsal ulnar border Insertion Base of the 5th metacarpal (dorsal)

Test Movement

Ulnar deviation of the wrist against resistance (forearm supported palm-down)

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 Ulnaris 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 Ulnaris?

Ulnar (little-finger) side of the forearm, a few cm distal to the elbow; palpate the muscle belly during ulnar deviation of the wrist. Orientation: Parallel to the muscle fibres, 2 cm inter-electrode distance. Not covered by SENIAM — placement per Criswell 2011.

Which test movement activates the M. Extensor Carpi Ulnaris?

Ulnar deviation of the wrist against resistance (forearm supported palm-down). 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 Ulnaris a SENIAM-recommended muscle?

No. The M. Extensor Carpi Ulnaris is not included in the official SENIAM catalogue. The electrode position documented here follows the established protocol per Criswell 2011.