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October 18, 2011
Asymmetric tonic limb posturing is a useful lateralizing sign in secondarily generalized tonic–clonic seizures. It is characterized by the rigid extension of one arm at the elbow, often with the fist clenched and flexed at the wrist, while the opposite extremity is flexed at the elbow. This has been named the "Figure 4 sign" and it occurs during the tonic phase of a generalized tonic-clonic seizure. The ictal onset is contralateral to the extended arm in 92% of cases . Asymmetric tonic limb posturing may be related to asymmetrical activation of the supplementary motor area or prefrontal areas .
Submitted by: Seby John MD and Dimitrios A. Nacopoulos MD; Neurology Residents, Cleveland Clinic, Cleveland, Ohio
Disclosures: Drs. Seby and Nacopoulos have no disclosures.
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