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The lumbar multifidus muscle in polysegmentally innervated.
P B Wu1, E S Date, W S Kingery
1Department of Physical Medicine and Rehabilitation, Palo Alto Medical Clinic, Palo Alto, California, USA.
Electromyography and Clinical Neurophysiology
|January 13, 2001
Summary
The lumbar multifidus muscle is innervated at multiple levels, meaning it receives nerve input from several spinal segments. This polysegmental innervation challenges the use of multifidus electromyography for pinpointing specific lumbar radiculopathy levels.
Area of Science:
- Anatomy and Physiology
- Neuroscience
- Musculoskeletal Research
Background:
- Investigating the innervation patterns of deep back muscles is crucial for understanding spinal biomechanics and pain.
- The lumbar multifidus muscle plays a significant role in spinal stability.
- Previous understanding of multifidus innervation was limited, particularly regarding polysegmental innervation.
Observation:
- A prospective case study was performed on a patient with chronic mechanical low back pain.
- The study involved bilateral percutaneous radiofrequency neurotomy of the medial branches of the L3 dorsal rami.
- Electromyography (EMG) was used to examine the L2-5 multifidi before and after the neurotomy procedure.
Findings:
- Post-neurotomy, EMG revealed positive sharp waves and fibrillations in the L3-L5 multifidi.
- This demonstrates electrophysiological evidence of polysegmental innervation of the lumbar multifidus muscle in humans.
- The medial branch of the lumbar dorsal ramus innervates the multifidus at multiple spinal levels.
Implications:
- The findings indicate that the lumbar multifidus muscle is polysegmentally innervated.
- Electromyography of the multifidus muscle is not suitable for identifying a specific level of lumbar radiculopathy.
- This challenges current diagnostic approaches for low back pain and radicular syndromes.