In twenty-three patients with cerebral palsy and functional spastic
hemiplegia, the contracted thenar-adductor space of the involved hand was
evaluated by electromyography. The needle electromyogram was used to
determine if the patient had selective control of the adductor muscle. In
eight patients only partial myotomy of the adductor muscle during z-plasty
of the web was performed because selective control of that muscle was
present during either grasp or release. In four patients a complete release
was done, and in two of them the ability to pinch was impaired.