muscle spindle: Meaning and Definition of

mus'cle spin"dle

Pronunciation: [key]
  1. a proprioceptor in skeletal muscle, composed of striated muscle fibers and sensory nerve endings in a connective tissue sheath, that conveys information via the spinal nerves on the state of muscle stretch, important in the reflex mechanism that maintains body posture.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.