The testicles of infants are very flaccid, and it is recommended to go to the hospital for an examination to identify the cause of the flaccidity. Possible causes: First, traffic syringomyelia due to unclosed sphincter, which may show changes in scrotal volume and size, with localized swelling or appearance of increased volume. It is obvious when standing, obvious when crying, and disappears when lying down. Ultrasound examination of the scrotum is needed to find out if there is a traffic syringomyelia or if there is an unclosed sphincter. Secondly, in cryptorchidism, the testicles may be located under the skin or within the epididymal ducts instead of the scrotum. It is necessary to touch the scrotum to understand whether there is scrotal emptiness, whether the testicles are in place bilaterally and whether the size is normal, and if necessary, to conduct ultrasound examination of both testicles to further rule out the existence of cryptorchidism. Thirdly, when the external environment is hot, the scrotal skin can be stretched, showing the condition of scrotal relaxation. The testicles or scrotum can be loose. At this time, the testicles are well positioned on palpation and there is no local swelling, so dynamic observation is needed.