Ultrastructure of muscle spindles in C57BL/6J dy2J/dy2J dystrophic mice.

The sensory organs of skeletal muscles, the muscle spindles, were examined using electron microscopy in dy2J/dy2J dystrophic mice. Despite widespread damage to the extrafusal (skeletomotor) fibres the intrafusal (spindle) fibres appeared normal and seemed resistant to the aetiological factors for murine dystrophy.