The disappearance of the anal canal reflex belongs to one of the shallow reflexes of the human nerve reflexes. When a person lies flat, holds the lower limb high and straight, and strokes a small needle across the perineal area, the external anal sphincter will contract. The afferent nerve is the pubic nerve, and the center is in the posterior horn cell column of sacral medulla 4-5 and the anterior horn cell sex of the same segment, and the efferent nerve is the pubic nerve. The external anal sphincter receives bilateral perineal nerve innervation. The anal reflex still exists when there is damage to the pyramidal fasciculus or peripheral nerve on one side, and disappears when there is damage to the pyramidal fasciculus on both sides or damage to the cauda equina. The loss of anal canal reflex can be shown in elderly people with fecal incontinence. Clinical manifestations of loss of the anal canal reflex: The manifestation is a varying degree of loss of control of defecation and exhaustion. Patients with mild incontinence lose control of exhaustion and liquid stools, and their underwear is occasionally soiled. Patients with severe incontinence also have no control over solid feces and exhibit frequent anal discharge of feces, which can be avoided if the patient is able to find a toilet quickly and avoid soiling their underwear. The quality of life and physical and mental health of patients with this disorder are often affected by prolonged dampness and uncleanliness of the anal perineal area, contamination of clothing and bed linen, etc. Clinical examination: 1. Physical examination reveals moist and unclean anal perineal area, eczema ulcer scar, perianal skin scar, anal flaccidity, and sometimes rectal prolapse. 2, finger examination can be palpated hard fecal mass or tumor, etc. There can be anal sphincter relaxation and stretching, and its contraction force is weakened or disappeared. 3, careful examination can accurately determine the site of contractile weakness and can show the loss of anal canal reflex. Prevention of loss of anal reflex: 1. Treatment of anorectal injury: Anal function damage caused by anorectal injury is related to the cause and extent of the injury, therefore, timely and correct treatment of the injury is often an important part of preserving defecation function. 2, pay attention to the treatment of anal diseases: anal congenital in doing repair and forming surgery, must pay attention to the use of the original anal sphincter, especially the reconstruction of the anal canal rectal ring, is the key to restore defecation function after surgery. The treatment of the disappearance of the anal canal reflex: 1, the treatment of anorectal injury: the damage to anal function caused by anorectal injury is related to the cause and extent of its injury therefore, timely and correct treatment of the injury is often an important part of the preservation of defecation function. 2, pay attention to the treatment of anorectal diseases: anal congenital in doing repair and forming surgery, must pay attention to the use of the original anal sphincter, especially the reconstruction of the anal canal rectal ring, is the key to restore defecation function after surgery.