title: C5-8 brachial plexus root injury: the "T-1 hand".
abstract: OBJECTIVE
  Classically, C5-7 root injuries of the brachial plexus have been associated with palsies of shoulder abduction/external rotation, elbow flexion/extension, and wrist, thumb, and finger extension. However, current myotome maps generally indicate that C-8 participates in the innervation of thumb and finger extensors. Therefore, the authors have hypothesized that, for palsies of the thumb and finger extensors, the injury should affect the C-5 through C-8 roots.
  
  
  METHODS
  The authors tested their hypothesis in 30 patients with upper-type palsies of the brachial plexus. They traced a correlation between clinical findings and root injury, as documented by CT myelography, direct visualization during surgery, and electrophysiological studies.
  
  
  RESULTS
  In C5-8 root injuries, shoulder abduction and external rotation were paralyzed, and in all patients, wrist extensors were paralyzed. However, in 22 of the 30 patients, wrist extension was possible, because of contraction of the extensor digitorum communis and extensor pollicis longus. Wrist flexion and pronation also were preserved. The T-1 root contributed significantly to innervation of the thumb and finger flexors, ensuring 34% grasping and 40% pinch strength relative to the normal side. Hand sensation was largely preserved.
  
  
  CONCLUSIONS
  Based on the authors' observations, they suspect that the clinical scenario previously attributed to a C5-7 root injury is, in fact, a C5-8 root injury. The authors propose referring to this partial palsy of the brachial plexus as a "T-1 hand."
authors.affiliation: Center of Biological and Health Sciences, Department of Neurosurgery, University of the South of Santa Catarina (Unisul), Tubarão, SC, Brazil. drbertelli@gmail.com
authors.forename: Jayme Augusto
authors.initials: JA
authors.lastname: Bertelli
authors.forename: Marcos Flávio
authors.initials: MF
authors.lastname: Ghizoni
mesh_terms: D000293:Adolescent; D000328:Adult; D001917:Brachial Plexus / Q000293:injuries* / Q000503:physiopathology*; D020516:Brachial Plexus Neuropathies / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D002574:Cervical Vertebrae; D004551:Elbow Joint / Q000294:innervation / Q000502:physiology; D005260:Female; D005385:Fingers / Q000294:innervation / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D010243:Paralysis / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D012785:Shoulder Joint / Q000294:innervation / Q000502:physiology; D013126:Spinal Nerve Roots / Q000293:injuries* / Q000503:physiopathology*; D013933:Thumb / Q000294:innervation / Q000502:physiology; D014955:Wrist Joint / Q000294:innervation / Q000502:physiology; D055815:Young Adult