Answer:
A muscle spindle fiber is composed of several specialized thin muscle fibers innervated by sensory neurons.
A muscle spindle consists of the several divided muscle fiber which are enclosed in the spindle-shaped connective tissue sac.
Muscle spindle consists of 5-14 muscle fibers. They are dynamic nuclear bag fiber, nuclear chain fibers and static nuclear bag fibers.
They form the muscles of he body that helps in the movement of the skeletal system and movement of the body.