Split hand syndrome

This article is about the neurological syndrome. For the congenital disorder, see split hand.
Split hand syndrome
SpecialtyNeurological

In medicine, split hand syndrome is a neurological syndrome in which the hand muscles on the side of the thumb (lateral, thenar eminence) appear wasted, whereas the muscles on the side of the little finger (medial, hypothenar eminence) are spared. Anatomically, the abductor pollicis brevis and first dorsal interosseous muscle are more wasted than the abductor digiti minimi.[1]

If lesions affecting the branches of the ulnar nerve that run to the wasted muscles are excluded, the lesion is almost sure to be located in the anterior horn of the spinal cord at the C8-T1 level.[2] It has been proposed as a relatively specific sign for amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease).[1][3] It can also occur in other disorders affecting the anterior horn, such as spinal muscular atrophy, Charcot-Marie-Tooth disease, poliomyelitis and progressive muscular atrophy.[2][4] A slow onset and a lack of pain or sensorial symptoms are arguments against a lesion of the spinal root or plexus brachialis.[4] To an extent, these features can also be seen in normal aging (although technically, the apparent muscle wasting is sarcopenia rather than atrophy).[5]

The term split hand syndrome was first coined in 1994 by a researcher from the Cleveland Clinic called Asa J. Wilbourn.[6][7]

  1. ^ a b Kuwabara S, Sonoo M, Komori T, et al. (April 2008). "Dissociated small hand muscle atrophy in amyotrophic lateral sclerosis: frequency, extent, and specificity". Muscle Nerve. 37 (4): 426–30. doi:10.1002/mus.20949. PMID 18236469. S2CID 18500530.
  2. ^ a b Split hand syndrome. Stedman's Medical Dictionary. Retrieved August 13, 2008.
  3. ^ Kuwabara S, Mizobuchi K, Ogawara K, Hattori T (July 1999). "Dissociated small hand muscle involvement in amyotrophic lateral sclerosis detected by motor unit number estimates". Muscle Nerve. 22 (7): 870–3. doi:10.1002/(SICI)1097-4598(199907)22:7<870::AID-MUS9>3.0.CO;2-O. PMID 10398204. Archived from the original on 2013-01-05.
  4. ^ a b Schelhaas HJ, van de Warrenburg BP, Kremer HP, Zwarts MJ (December 2003). "The "split hand" phenomenon: evidence of a spinal origin". Neurology. 61 (11): 1619–20. doi:10.1212/01.wnl.0000096009.50213.6c. PMID 14663056. S2CID 39361741.
  5. ^ Voermans NC, Schelhaas HJ, Munneke M, Zwarts MJ (December 2006). "Dissociated small hand muscle atrophy in aging: the 'senile hand' is a split hand". Eur J Neurol. 13 (12): 1381–4. doi:10.1111/j.1468-1331.2006.01477.x. PMID 17116225. S2CID 26868415.
  6. ^ Wilbourn AJ, Sweeney PJ (1994). "Dissociated wasting of medial and lateral hand muscles with motor neuron disease". Can J Neurol Sci. 21 (S2): S9.
  7. ^ Wilbourn AJ (January 2000). "The "split hand syndrome"". Muscle Nerve. 23 (1): 138. doi:10.1002/(SICI)1097-4598(200001)23:1<138::AID-MUS22>3.0.CO;2-7. PMID 10590421. Archived from the original on 2013-01-05.