muscle spindle

plural muscle spindles

1. A stretch receptor within the body of a skeletal muscle that detects changes in the length of the muscle.

   1 more example

   In conclusion, it must be emphasized that although we now know something of the detailed structure of the muscle spindle, and the functional properties of its component parts, the exact role or roles it plays in voluntary or reflex muscle ovements are still a matter for further speculation and experiment

   1974, Felix Beck, John Benjamin Lloyd, The Cell in Medical Science, page 536