The nerve that controls urination and defecation is the sacral nerve, which is divided into five segments, and the main one that controls urination and defecation is the sacral ganglion 3-5, which is the spinal cone. The spinal cord has two functions, the first is to serve as a relay station for the upstream and downstream conduction pathways, and the second can serve as a reflex center. Therefore, after the damage of sacral nerve, especially the damage of 3-5, the interruption of reflex pathway will cause the loss of sensation in the anus or perineum in a saddle-like distribution, which is also called saddle avoidance in medical science, and patients will also experience the loss of anal reflex and sexual dysfunction. The spinal cone is the parasympathetic center of sphincter function, which can cause urinary and fecal dysfunction after damage, such as urinary retention, urinary incontinence, constipation or fecal incontinence, mostly due to trauma or tumor, and inflammation and other causes.