The muscle spindle detects excessive stretch within the muscle?

Yes, the muscle spindle is a proprioceptive organ that detects excessive stretch within the muscle. It is located within the muscle tissue and consists of specialized muscle fibers called intrafusal fibers. These fibers are innervated by sensory neurons, which send signals to the spinal cord and brain when the muscle is stretched. This information is used to reflexively contract the muscle and prevent it from being damaged.