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Split-hand sign: clinical feature of spinal bulbar muscular atrophy?
  1. Steve Vucic
  1. Westmead Clinical School, University of Sydney, Westmead, New South Wales, Australia
  1. Correspondence to Professor Steve Vucic, Westmead, NSW 2145, Australia; steve.vucic{at}

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Split-hand signappears to be evident in spinalbulbar muscular atrophy and amyotrophic lateralsclerosis

Dissociated muscle atrophy is an established clinical phenomenon of amyotrophic lateral sclerosis (ALS), heralded by the split-hand sign which is clinically characterised by preferential wasting of thenar group of intrinsic hand muscles (abductor pollicis brevis (APB) and first dorsal interosseous (FDI)), when compared with the hypothenar group.1–3 The specificity of the split-hand phenomenon in ALS was further established by the split-hand index, a neurophysiological biomarker utilising motor amplitudes.4 Additionally, dissociated patterns of muscle atrophy in ALS may also be characterised by the split-hand plus (preferential dysfunction of thenar muscles compared with flexor pollicis longus),4 split-elbow (preferential weakness of biceps brachii compared with triceps muscle)5 and split-leg signs (preferential dysfunction of ankle plantar flexor compared with the dorsiflexor muscles). …

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  • Contributors This is an invited editorial. SV reviewed and wrote the paper.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Commissioned; internally peer reviewed.

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