Extrafusal muscle fiber Extrafusal muscle fiber Extrafusal muscle fibers are the skeletal standard muscle fibers that are innervated by alpha motor neurons and generate tension by contracting, thereby allowing for skeletal movement. They make up the large mass of skeletal muscle tissue and are attached to bone by fibrous tissue extensions (tendons). Each alpha motor neuron and the extrafusal muscle fibers innervated by it make up a motor unit. The connection between the alpha motor neuron and the extrafusal muscle fiber is a neuromuscular junction, where the neuron's signal, the action potential, is transduced to the muscle fiber by the neurotransmitter acetylcholine. Extrafusal
Bone pain (C fiber) sensory neurons. In combination, they can provide an initial burst of pain, initiated by the faster myelinated fibers, followed by a slower and longer-lasting dull pain initiated by unmyelinated fibers. Nociceptors responsible for bone pain can be activated via several mechanisms including deterioration of surrounding tissue, bone destruction, and physical stress which shears the bone, vascular, muscle, and nervous tissue. Common causes of bone and joint pain in adults, such as osteoarthritis and gouty arthritis are rare in children, as these diseases are a sequelae of chronic wear and tear for several years. The use of anesthetics within