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C5-8 brachial plexus root injury: the "T-1 hand"
Jayme Augusto Bertelli1, Marcos Flávio Ghizoni
1Center of Biological and Health Sciences, Department of Neurosurgery, University of the South of Santa Catarina (Unisul), Tubarão, SC, Brazil. drbertelli@gmail.com
Journal of Neurosurgery
|August 23, 2011
Summary
Brachial plexus injuries affecting thumb and finger extensors involve C5-8 roots, not just C5-7. This challenges traditional myotome maps and suggests a reclassification of these palsies as "T-1 hand" injuries.
Area of Science:
- Neurology
- Orthopedics
- Anatomy
Background:
- Traditionally, C5-7 brachial plexus root injuries are linked to specific motor deficits.
- Existing myotome maps suggest C-8 contributes to thumb and finger extensor innervation.
Purpose of the Study:
- To investigate the hypothesis that palsies of thumb and finger extensors result from C5-8 root injuries.
- To re-evaluate the anatomical basis of upper brachial plexus palsies.
Main Methods:
- A study of 30 patients with upper brachial plexus palsies was conducted.
- Clinical findings were correlated with root injury using CT myelography, surgical visualization, and electrophysiological studies.
Main Results:
- C5-8 root injuries caused paralysis of shoulder abduction/external rotation and wrist extensors in all patients.
- Wrist extension was preserved in 22/30 patients due to extensor digitorum communis and extensor pollicis longus.
- The T-1 root significantly contributed to thumb and finger flexors, preserving 34% grasp and 40% pinch strength; hand sensation was largely intact.
Conclusions:
- The clinical presentation previously attributed to C5-7 root injury is likely due to C5-8 root injury.
- The authors propose the term
- T-1 hand
- for this specific partial brachial plexus palsy pattern.
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