Skip to main content
Advertisement
  • Neurology.org
  • Journals
    • Neurology
    • Clinical Practice
    • Genetics
    • Neuroimmunology & Neuroinflammation
    • Education
  • Online Sections
    • Neurology Video Journal Club
    • Inclusion, Diversity, Equity, Anti-racism, & Social Justice (IDEAS)
    • Innovations in Care Delivery
    • Practice Buzz
    • Practice Current
    • Residents & Fellows
    • Without Borders
  • Collections
    • COVID-19
    • Disputes & Debates
    • Health Disparities
    • Infographics
    • Null Hypothesis
    • Patient Pages
    • Topics A-Z
    • Translations
  • Podcast
  • CME
  • About
    • About the Journals
    • Contact Us
    • Editorial Board
  • Authors
    • Submit a Manuscript
    • Author Center

Advanced Search

Main menu

  • Neurology.org
  • Journals
    • Neurology
    • Clinical Practice
    • Genetics
    • Neuroimmunology & Neuroinflammation
    • Education
  • Online Sections
    • Neurology Video Journal Club
    • Inclusion, Diversity, Equity, Anti-racism, & Social Justice (IDEAS)
    • Innovations in Care Delivery
    • Practice Buzz
    • Practice Current
    • Residents & Fellows
    • Without Borders
  • Collections
    • COVID-19
    • Disputes & Debates
    • Health Disparities
    • Infographics
    • Null Hypothesis
    • Patient Pages
    • Topics A-Z
    • Translations
  • Podcast
  • CME
  • About
    • About the Journals
    • Contact Us
    • Editorial Board
  • Authors
    • Submit a Manuscript
    • Author Center
  • Home
  • Latest Articles
  • Current Issue
  • Past Issues
  • Residents & Fellows

User menu

  • Subscribe
  • My Alerts
  • Log in
  • Log out

Search

  • Advanced search
Neurology
Home
The most widely read and highly cited peer-reviewed neurology journal
  • Subscribe
  • My Alerts
  • Log in
  • Log out
Site Logo
  • Home
  • Latest Articles
  • Current Issue
  • Past Issues
  • Residents & Fellows

Share

December 09, 2003; 61 (11) Brief Communications

The “split hand” phenomenon

Evidence of a spinal origin

H. J. Schelhaas, B. P.C. van de Warrenburg, H. P.H. Kremer, M. J. Zwarts
First published December 8, 2003, DOI: https://doi.org/10.1212/01.WNL.0000096009.50213.6C
H. J. Schelhaas
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
B. P.C. van de Warrenburg
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
H. P.H. Kremer
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
M. J. Zwarts
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Full PDF
Citation
The “split hand” phenomenon
Evidence of a spinal origin
H. J. Schelhaas, B. P.C. van de Warrenburg, H. P.H. Kremer, M. J. Zwarts
Neurology Dec 2003, 61 (11) 1619-1620; DOI: 10.1212/01.WNL.0000096009.50213.6C

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Permissions

Make Comment

See Comments

Downloads
761

Share

  • Article
  • Figures & Data
  • Info & Disclosures
Loading

Abstract

The clinical phenomenon of a split hand, dominant muscle atrophy in the thenar as compared to the hypothenar complex, has been used to support the theory of primary cortical degeneration in amyotrophic lateral sclerosis. However, the same phenomenon, both clinically and electrophysiologically, was observed in three diseases with a second but not first motor neuron affection: autosomal dominant spinal muscular atrophy, spinocerebellar ataxia type 3, and juvenile muscular atrophy. Neurogenic loss in a split hand distribution points to a spinal instead of cortical origin.

The term split hand, first coined by Willbourn et al.,1 refers to a type of hand muscle atrophy in which the muscles of the lateral aspect of the hand (first dorsal interosseus and thenar) are more affected than those of the medial aspect (hypothenar). Willbourn et al. described the split hand in the context of amyotrophic lateral sclerosis (ALS) and stated that, although not limited to ALS, this phenomenon seems to be specific for anterior horn disease.2 However, as the thenar and hypothenar complex have the same segmental supply and a different cortical presentation, others suggested that this pattern of muscle wasting is of cortical origin.3 As such, the dissociation of hand muscle wasting is considered to confirm the theory of cortical dysfunction with anterograde degeneration as the initial step in the pathogenesis of ALS. We wondered whether the split hand is also observed in disorders that are known to be characterized by lower motor neuron degeneration in the absence of cortical degeneration. Therefore, we performed nerve conduction studies in patients with autosomal dominant distal spinal muscular atrophy (DSMA), spinocerebellar ataxia type 3 (SCA-3), and juvenile muscular atrophy (JMA).

Methods.

Patients.

All five affected members of a three-generation family with DSMA, five consecutive patients with SCA-3, and three patients with JMA participated in the study. Each patient was subjected to a thorough neurologic and electrophysiologic examination.

Nerve conduction studies.

Nerve conduction studies were recorded with a Medelec Synergy EMG system (Oxford Medical Instruments). Skin temperature was maintained at 34 °C and limbs were warmed if necessary. Compound muscle action potentials (CMAP) of the thenar and hypothenar complexes were evoked by supramaximal peripheral stimulation of the median and ulnar nerves. One patient with SCA-3 (data not shown) with neurophysiologic evidence of a carpal tunnel syndrome was excluded.

Statistics.

Analysis was done using binomial distribution statistics.

Results.

The five members of the DSMA family showed a mild disease severity and slow progression, with lower limb predominance. Dissociated hand muscle wasting was evident in four of five members of the DSMA family.

The phenotype of the five patients with SCA-3 was characterized by a late onset (40 to 60 years), slow progression, cerebellar ataxia, cramps, fasciculations, and muscle atrophy. A split hand pattern of muscle atrophy was present in four of five patients with SCA-3.

The clinical course of the three (male) patients with JMA was characterized by an insidious onset, slow progression, and, ultimately, stabilization of disease. Dominant muscle atrophy in the thenar as compared to the hypothenar complex was present in two patients with JMA. One patient with JMA showed a reverse pattern of muscle wasting, with sparing of the thenar and prominent involvement of the hypothenar muscles. Intriguingly, this patient showed lower focal cervical cord atrophy on cervical MRI.

In four of five subjects with DSMA, in all patients with SCA-3, and in two patients with JMA, the electrically evoked hypothenar CMAP was larger than the thenar CMAP (table).

View this table:
  • View inline
  • View popup

Table 1 Clinical features and nerve conduction studies in five patients of a three-generation family with autosomal dominant DSMA, in five patients with SCA-3, and in three patients with JMA

Concerning a total population of 13 patients, there was a binomial distribution and a prior probability of 0.5 (no significant difference in the thenar as compared to the hypothenar CMAP in normal controls), with 13 trials and two failures: p = 0.0111 (one-tailed sign test).

Discussion.

Our results support the theory that a dissociation of hand muscle atrophy, in which the thenar muscles are more affected than the hypothenar muscles, is an important clinical feature that localizes the lesion to the anterior horn. Greater thenar than hypothenar involvement is also seen in patients with T1 root involvement and in patients with lower trunk plexus involvement. However, the indefinite onset with slow progression over years in the absence of pain or sensory symptoms makes the possibility of additional radicular or plexus involvement unlikely.

DSMA, SCA-3, and JMA are clinically and genetically very different disorders. Still, distal muscle atrophy and motor neuron degeneration is a common feature in all. Autosomal dominant DSMA is a rare, genetically heterogeneous lower motor neuron disorder that may be difficult to distinguish clinically from type II Charcot-Marie-Tooth disease.4 SCA-3 or Machado-Joseph disease (MJD) is an autosomal dominant cerebellar ataxia caused by CAG trinucleotide repeat expansions in the MJD/SCA-3 gene.5 The phenotype of the five patients with SCA-3 studied here is compatible with a SCA-3 subtype (subtype III)6 in which late onset, slow progression, cramps, fasciculations, and muscle atrophy are typical features and degeneration of anterior horn cells a common neuropathologic finding.7 JMA is a focal amyotrophy with unilateral or asymmetric bilateral wasting of C7-Th1 innervated muscles.8 Whereas some studies suggest that JMA is an intrinsic motor neuron disease,9 others favor the view that the disorder results from mechanical distortion of the cervical spinal cord due to neck flexion during growth.10

Because the pathophysiologic mechanisms of DSMA, SCA-3, and JMA are presumably very different, the observation of a split hand in these diseases weakens the theory of the cortical origin of degeneration in ALS and supports the theory of an intrinsic vulnerability of spinal motor neurons subserving the thenar complex.

  • Received April 28, 2003.
  • Accepted August 13, 2003.

References

  1. ↵
    Willbourn AJ. Dissociated wasting of medial and lateral hand muscles with motor neuron disease. Can J Neurol Sci . 1994; 21 (suppl 2): S9.
    OpenUrl
  2. ↵
    Willbourn AJ. The “split hand syndrome.” Muscle Nerve . 2000; 23: 138.
    OpenUrl
  3. ↵
    Weber M, Eisen A, Steward H, Hirota N. The split hand in ALS has a cortical basis. J Neurol Sci . 2000; 180: 66–70.
    OpenUrlCrossRefPubMed
  4. ↵
    De Angelis MV Gatta V, Stuppia L, Passamonti L, Gambi D, Uncini A. Autosomal dominant distal spinal muscular atrophy: an Italian family not linked to 12q24 and 7p14. Neuromuscul Disord . 2002; 12: 26–30.
    OpenUrlCrossRefPubMed
  5. ↵
    Kawaguchi Y, Okamoto T, Taniwaki M, et al. CAG expansions in a novel gene for Machado-Joseph disease at chromosome 14q32.1. Nat Genet . 1994; 8: 221–228.
    OpenUrlCrossRefPubMed
  6. ↵
    Lopes-Cendes I, Silveira I, Maciel P, et al. Limits of clinical assessment in the accurate diagnosis of Machado-Joseph disease. Arch Neurol . 1996; 53: 1168–1174.
    OpenUrlCrossRefPubMed
  7. ↵
    Kinoshita A, Hayashi M, Oda M, Tanabe H. Clinicopathological study of the peripheral nervous system in Machado-Joseph disease. J Neurol Sci . 1995; 130: 48–58.
    OpenUrlCrossRefPubMed
  8. ↵
    Hirayama K, Tsubaki T, Toyokura T. Juvenile muscular atrophy of unilateral upper extremity. Neurology . 1963; 13: 373–380.
  9. ↵
    Schroder R, Keller E, Flacke S, et al. MRI findings in Hirayama’s disease: flexion-induced myelopathy or intrinsic motor neuron disease? J Neurol . 1999; 246: 1069–1074.
    OpenUrlCrossRefPubMed
  10. ↵
    Hirayama K, Tokumaru Y. Cervical dural sac and spinal cord in juvenile muscular atrophy of distal upper extremity. Neurology . 2000; 54: 1922–1926.
    OpenUrlAbstract/FREE Full Text

Disputes & Debates: Rapid online correspondence

No comments have been published for this article.
Comment

REQUIREMENTS

If you are uploading a letter concerning an article:
You must have updated your disclosures within six months: http://submit.neurology.org

Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.

If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.

Submission specifications:

  • Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
  • Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
  • Submit only on articles published within 6 months of issue date.
  • Do not be redundant. Read any comments already posted on the article prior to submission.
  • Submitted comments are subject to editing and editor review prior to posting.

More guidelines and information on Disputes & Debates

Compose Comment

More information about text formats

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Author Information
NOTE: The first author must also be the corresponding author of the comment.
First or given name, e.g. 'Peter'.
Your last, or family, name, e.g. 'MacMoody'.
Your email address, e.g. higgs-boson@gmail.com
Your role and/or occupation, e.g. 'Orthopedic Surgeon'.
Your organization or institution (if applicable), e.g. 'Royal Free Hospital'.
Publishing Agreement
NOTE: All authors, besides the first/corresponding author, must complete a separate Publishing Agreement Form and provide via email to the editorial office before comments can be posted.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Vertical Tabs

You May Also be Interested in

Back to top
  • Article
    • Abstract
    • Methods.
    • Results.
    • Discussion.
    • References
  • Figures & Data
  • Info & Disclosures
Advertisement

Related Articles

  • No related articles found.

Topics Discussed

  • All Spinal Cord
  • Anterior nerve cell disease
  • Amyotrophic lateral sclerosis

Alert Me

  • Alert me when eletters are published
Neurology: 99 (6)

Articles

  • Ahead of Print
  • Current Issue
  • Past Issues
  • Popular Articles
  • Translations

About

  • About the Journals
  • Ethics Policies
  • Editors & Editorial Board
  • Contact Us
  • Advertise

Submit

  • Author Center
  • Submit a Manuscript
  • Information for Reviewers
  • AAN Guidelines
  • Permissions

Subscribers

  • Subscribe
  • Activate a Subscription
  • Sign up for eAlerts
  • RSS Feed
Site Logo
  • Visit neurology Template on Facebook
  • Follow neurology Template on Twitter
  • Visit Neurology on YouTube
  • Neurology
  • Neurology: Clinical Practice
  • Neurology: Genetics
  • Neurology: Neuroimmunology & Neuroinflammation
  • Neurology: Education
  • AAN.com
  • AANnews
  • Continuum
  • Brain & Life
  • Neurology Today

Wolters Kluwer Logo

Neurology | Print ISSN:0028-3878
Online ISSN:1526-632X

© 2022 American Academy of Neurology

  • Privacy Policy
  • Feedback
  • Advertise