Muscle Spindles

**Definition:** Skeletal muscle structures that function as the MECHANORECEPTORS responsible for the stretch or myotactic reflex (REFLEX, STRETCH). They are composed of a bundle of encapsulated SKELETAL MUSCLE FIBERS, i.e., the intrafusal fibers (nuclear bag 1 fibers, nuclear bag 2 fibers, and nuclear chain fibers) innervated by SENSORY NEURONS.

**Tree numbers:** - A08.675.650.915.750.500 - A08.800.950.750.500 - A10.690.552.500.750 - A11.671.650.915.750.500

**Synonyms:** - Muscle Stretch Receptors - Neuromuscular Spindles - Receptors, Stretch, Muscle - Stretch Receptors, Muscle