Generally speaking, the baby’s body as a child, the bones are not fully developed, so their flexibility is not what we can imagine, and can even be compared to those acrobatic performance of flexibility, for some babies like to lean back we do not have to worry too much about the baby flash waist. On the contrary, if it is due to the adult’s hold incorrectly lead to the baby flashback is possible, so we hold the baby when try not to stand to hold, and be sure to put the baby’s waist to support. Acute lumbar back sprain, commonly known as “flashback”, is more common in clinical practice, especially in manual laborers; young and old patients are less. The scope of this disease includes the lower back to the sacroiliac myofascial tissue, that is, the thoracolumbar section and lumbosacral two anatomical regions. So, for babies, they can’t explain themselves, how do we tell when they do flash their back? Generally speaking, if the baby flashed waist we can not find, this time we have to carefully observe, if the baby crying for no reason, adults no matter how to coax the baby, and then is to hold the baby if the baby’s waist to touch the baby instead of crying more, then we have to pay attention to see if the baby flashed waist, usually can give the baby a gentle massage can be corrected flashing waist. Flash waist, for adults may be very painful, but for babies may be very common, but the degree of flash waist is not consistent, if only a slight flash waist, may be the baby crying a few minutes will be fine, but if it is serious, we have to go to the hospital for observation.