Ultrasonically induced morphological changes in the mammalian neonatal spinal cord.

Light and electron microscopy were employed to examine ultrasonically irradiated murine neonate spinal cords. Spinal cord damage was always associated with functional changes, i.e. hind limb paralysis, and was never apparent in initially paralyzed specimens which had recovered function. Damage occurred preferentially at the periphery of the spinal cord and on the ventral side, though the ultrasound was incident on the dorsal side. The distribution of the damage suggests spinal column involvement and nonthermal effects that are enhanced by temperature elevation.