Lying on the side will be numb mainly manifested in the following two aspects: First, lying on the side of the body due to a long-term side of the pressure situation, to cause a side of the hand ischemia, hypoxia state and affect the blood circulation of the hand, so long-term will cause numbness of the limbs, and some patients also have the feeling of limb pain. Second, the hand will be numb after lying on the side, mostly seen in patients with cervical disc herniation. This is due to the side lying posture is easily caused by the brachial plexus nerve involvement, there will be the median nerve or radial nerve, ulnar nerve compression, prolonged nerve compression will cause numbness in the limbs, numbness will be relieved after the activity of the hand. In short, the numbness of the hand after lying on the side is mainly considered for the above two reasons.