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Magnetic mapping of human cervical nerve roots: variation in normal subjects
1Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322.
Electroencephalography and Clinical Neurophysiology
|June 1, 1993
Summary
Cervical magnetic stimulation can map nerve root innervation using a butterfly coil. This technique shows reproducible muscle activation patterns, aiding in the study of human segmental innervation.
Area of Science:
- Neuroscience
- Biomedical Engineering
Background:
- Cervical magnetic stimulation preferentially targets neural foramina.
- Optimal stimulation occurs with a transverse electric field orientation relative to the spine.
Purpose of the Study:
- To investigate the potential of cervical magnetic stimulation for mapping segmental innervation.
- To determine muscle activation patterns and their relationship to specific cervical nerve roots.
Main Methods:
- Utilized a butterfly stimulus coil positioned horizontally for cervical magnetic stimulation.
- Recorded compound motor action potentials from upper extremity muscles in 15 healthy adults.
- Analyzed responses at 1 cm intervals along the cervical-thoracic spine, with needle electrode verification and X-ray correlation.
Main Results:
- Compound motor action potentials exhibited reproducible, reproducible morphologies that changed predictably with coil movement, indicating specific nerve root origins.
- Most subjects displayed muscle activation sequences consistent with established segmental innervation patterns.
- Variations in nerve root supply were observed in 5 subjects, highlighting potential individual differences.
Conclusions:
- Cervical magnetic stimulation, particularly with a butterfly coil, is a viable method for mapping segmental innervation in humans.
- The technique offers a non-invasive approach to study variations in human nerve root anatomy and function.