Electrode Placement (SENIAM)
2 finger widths lateral to L1
Orientation: Parallel to the spine (vertical)
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.
Recording notes per Criswell 2011, site „Low-Back (Erector Spinae) at L-3“, p. 342
- Placement type
- Quasi-specific site Neighbouring muscles contribute noticeably to the signal — allow for crosstalk.
- Signal check
- Forward flexion of the torso and return to midline.
- Crosstalk from
- quadratus lumborum · gluteus maximus · latissimus dorsi
- Artefacts
- Skin distortion during flexion/extension → electrodes may slip or pop; ECG common on the left side.
Based on SENIAM recommendations (Hermens et al. 2000). Not an official SENIAM product. See all references →
· How electrodes are placed (guide)
· Glossary
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
Os sacrum, spinous processes of lumbar vertebrae, transverse processes of lower thoracic vertebrae
Insertion
Transverse processes of thoracic vertebrae, costal angles of ribs 2-12
Test Movement
Trunk extension from prone position against resistance
MVC reference test (Konrad 2005)
- Position
- Prone on a bench, trunk extension (upper body lifted against resistance).
- Fixation
- Legs and pelvis fixed on the bench.
- Resistance
- Manual resistance or belt across the upper back, extension against it.
- Control exercise
- Isolated back extension at a machine as the check exercise.
Konrad: a very productive position — the whole posterior chain is facilitated, so gluteus and hamstring maxima may appear here as well.
Konrad P. The ABC of EMG. Noraxon; 2005, p. 32. Konrad describes this test at group level; it applies to all muscles of the group. · Why and how to normalise to MVC
Clinical Applications
Common use cases for surface EMG measurement of the M. Longissimus Thoracis:
- Chronic low back pain therapy
- Postural correction for scoliosis
- Deadlift and squat biomechanics
Measure M. Longissimus Thoracis 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.
Frequently Asked Questions
Where do I place the EMG electrode on the M. Longissimus Thoracis?
2 finger widths lateral to L1. Orientation: Parallel to the spine (vertical). Based on the official SENIAM recommendations (Hermens et al. 2000).
Which test movement activates the M. Longissimus Thoracis?
Trunk extension from prone position against resistance. This movement is part of the SENIAM protocol for standardized contraction verification.
Is the M. Longissimus Thoracis a SENIAM-recommended muscle?
Yes. The M. Longissimus Thoracis is one of 26 muscles for which the SENIAM project has published official surface EMG electrode placement recommendations.
Related Muscles in This Region
Preview — open the 3D viewer to rotate the model and check neighbouring muscles.
View in 3D Viewer