Sacral reflexes: physiology and clinical application.

Sacral reflexes consist of motor responses in the pelvic floor and sphincter muscles evoked by stimulation of sensory receptors in pelvic skin, anus, rectum, or pelvic viscera. These responses may be elicited by physical or electrical stimuli. They have been used in research studies of the pathophysiology of pelvic floor and anorectal disorders and many have been recommended for diagnostic use. These reflexes are described and discussed in this review. More rigorous evaluation of their value in the clinical assessment and care of patients with pelvic floor and sphincter disorders is required. Currently direct comparisons of the value of particular responses are generally not available, and few of these reflexes have proven validity for use in clinical diagnosis.