The target phenomenon in human muscle: a comparative light microscopic histochemical and electron microscopic study.

A large number of target fibres is observed in a muscle biopsy from a patient with an acute flaccid paraplegia of the lower limbs due to a polyneuroradiculopathy of unknown origin. With the electron microscope up to 4 structural zones are seen in the target fibers. The histochemical and ultrastructural observations in this case, suggest that the "target fiber" phenomenon is due to a disturbed trophic influence of the nervous system.