Sleeping with legs crossed may be due to the presence of nervous system hyperexcitability, extrapyramidal lesions or muscle spasms, among other causes. It may also be a result of poor sleeping habits. The specific causes are as follows: 1. Nervous system excitability is too high: this kind of patients may have excessive excitement, nervousness, fear and so on in the near future. This will make the patient’s nervous system excitability increased significantly. During sleep, unconscious nervous system impulses may occur, leading to involuntary activity of the lower limbs. 2. Extrapyramidal lesions: In some patients with extrapyramidal lesions such as Parkinson’s syndrome, a resting tremor may occur due to abnormalities in the nerve conduction pathways. Thereafter, the patient may develop the above symptoms. 3. Muscle spasms: These patients often suffer from overworked muscles in the lower limbs, calcium deficiency or cold in the lower limbs. After that, patients are prone to muscle spasm of the lower limbs during sleep, which will lead to the above symptoms. In addition, it may also be that the sleeping posture is not good, so it is good to pay attention to the sleeping posture. There may also be other reasons for the symptoms of leg crossing, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.