Anal reflex

Definition:
The superficial anal reflex tests the integrity of a reflex arc involving S4 and S5 spinal segments.

Test procedure:
Ensure all ethical considerations are met regarding informed consent to examination. Lie the patient on their side with the knees flexed, and gently stroke the anal margin with a suitable implement such as an orange stick. Watch for motion of the anal sphincter.

Test findings:
A normal response would involve visible contraction of the anal sphincter, whereas a positive finding would be if this were absent. This may indicate a local lesion such as cauda equine syndrome, or a pyramidal tract lesion.

Considerations:
Ensure that the patient is reasonably comfortable and relaxed; a reflex cannot be elicited if the anal sphincter is contracted.