The pubic symphysis is an important part of the pelvis, and when there is trauma, the pubic symphysis becomes separated. If there is a separation of the pubic symphysis, the correct sleeping position should be the flat position, that is, the supine position, because in the supine position the pelvis is under minimal stress, which is very beneficial for the recovery of the pubic symphysis. The pelvis is an annular structure, also known as the pelvic ring, and when a person is in the lateral position, the pressure on the pelvic ring is the greatest, and if one sleeps in the lateral position, it will easily lead to the separation of the pubic symphysis again. So when there is a separation of the pubic symphysis due to trauma, you should choose to sleep in a flat position, i.e. supine, rather than in a side-lying position, which is very unfavorable for the recovery of the separation of the pubic symphysis.