Hypotonia-paralytic dyskinesia: it involves the head, neck and waist, such as neck weakness, inability to raise the head, waist weakness, inability to straighten up and protrude the abdomen, inability to walk, inability to take steps and lift the legs and feet to drag the ground. This is a clinical manifestation of delayed-onset dyskinesia. So what is the reason for the appearance of neck weakness and inability to raise the head? The following is to see together. The production and maintenance of muscle tone is essentially a complex reflex activity called the tensor reflex. Tension reflex is manifested in two forms: 1, phase tension reflex: characterized by a shorter duration and produce greater muscle force, such as knocking the quadriceps tendon caused by the knee tendon reflex is a typical phase tension reflex. The phasic stretch reflex is the basis of phasic tension generation. 2, the tension tension reflex: in the muscle by the persistent mild pull, the pulled muscle produces continuous and smooth contraction. The tense stretch reflex is the basis of positional tension. The reflex arc of the tension reflex, also known as the gamma;-collar, consists of an afferent and an efferent component. (1) Muscle lesions of various origins result in damage to both types of pull receptors, causing hypotonia. (2) Peripheral nerve and nerve root lesions result in impairment of afferent and efferent gamma;-collaterals, causing hypotonia. (3) Spinal cord lesions cause damage to alpha;-motor neurons and gamma;-motor neurons, causing hypotonia. (4) Lesions of the brainstem reticular formation, cerebellum, extrapyramidal system, and cerebral cortex lead to disorders of central regulation of muscle tone, causing hypotonia.