Anal wink

The anal wink or anocutaneous reflex is the reflexive contraction of the external anal sphincter upon stroking of the skin around the anus or the head of the penis.

The absence of this reflex indicates that there is an interruption of the reflex arc, which may be in the sensory afferent limb or the motor efferent limb. The synapse between the afferent and efferent limbs occurs in the lowest sacral segments of the spinal cord.