Trapezius Pars Descendens (left) — SENIAM EMG Electrode Placement

Recording notes & source

per Criswell 2011, site „Upper Trapezius (Narrow)“, p. 289

Placement type: Specific site The signal originates predominantly from this muscle.
Signal check: Shoulder elevation (shrug) or lateral bending of the head.
Crosstalk from: middle trapezius fibres · levator scapulae · supraspinatus
Artefacts: ECG and breathing.

The position above follows SENIAM; the crosstalk and artefact notes apply to surface recording of this muscle in general.

Source: SENIAM (Hermens 2000) ↗

Hermens HJ, Freriks B, Disselhorst-Klug C, Rau G. Development of recommendations for SEMG sensors and sensor placement procedures. J Electromyogr Kinesiol. 2000;10(5):361-74.

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

Go deeper Why the Electrode Must Not Sit on the Innervation Zone → 10 Factors That Distort Your EMG Signal →

All 49 muscle protocols as a PDF — free

Print-ready for the lab or clinic: 79 pages of protocols (SENIAM + peer-reviewed), plus the SENIAM table, a placement checklist and a sensor comparison sheet as A4 sheets.

Anatomy & Function

The M. Trapezius Pars Descendens (Upper Trapezius) is a muscle of the head & neck region. It is responsible for elevation of scapula, lateral flexion of cervical spine, head extension. This muscle is one of 26 with official SENIAM-recommended surface EMG electrode placement. This page documents the exact electrode position, anatomical attachments and a standardized test movement based on Hermens et al. (2000).

Function Elevation of scapula, lateral flexion of cervical spine, head extension Origin External occipital protuberance, Lig. nuchae, Proc. spinosi C1–C7 Insertion Lateral third of clavicle, acromion Innervation Spinal accessory nerve (spinal portion) with twigs from C3–C4

Innervation after Perotto AO, Anatomical Guide for the Electromyographer, 5th ed. 2011 — an anatomical reference, not an electrode placement recommendation.

Clinical applications (SENIAM)

Jaw rehabilitation and TMJ disorders
Cervical posture analysis and muscle tension
Headache biofeedback (cervicogenic, tension-type)

Test Movement

Elevate shoulder against resistance (shoulder shrug)

Detail: sensor on the M. Trapezius Pars Descendens — Illustration shows the left side; the set-up is mirrored for the right side.

MVC reference test (Konrad 2005)

Position: Seated, arms hanging at the side; the test can be done on one side only.
Fixation: Arm fixed downwards: manually, with a strap to the floor, or by holding a load heavy enough to press the shoulder down.
Resistance: Shoulder elevation (shrug) against the fixed arm.

Konrad calls the load variant "difficult" — the load has to be heavy enough that the shoulder cannot rise.

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. Trapezius Pars Descendens 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? PicoBlue sensors

Frequently Asked Questions

Where do I place the EMG electrode on the M. Trapezius Pars Descendens?

50% on line from acromion to C7 spinous process. Orientation: Toward acromion–C7 line. Based on the official SENIAM recommendations (Hermens et al. 2000).

Which test movement activates the M. Trapezius Pars Descendens?

Elevate shoulder against resistance (shoulder shrug). This movement is part of the SENIAM protocol for standardized contraction verification.

Is the M. Trapezius Pars Descendens a SENIAM-recommended muscle?

Yes. The M. Trapezius Pars Descendens is one of 26 muscles for which the SENIAM project has published official surface EMG electrode placement recommendations.

M. Trapezius Pars Descendens

Electrode Placement (SENIAM)