Lightly stroke the anus on both sides with a cotton-tipped applicator. Which reflex is this testing?

• A. Anocutaneous reflex
• B. Abdominal reflexes
• C. Cremasteric reflex
• D. Plantar reflex

Answer: (A)

Focusing on a perineal cutaneous reflex, this maneuver elicits the anocutaneous (anal wink) reflex. Lightly stroking the perianal skin sends sensory signals via the pudendal nerve (sacral S2–S4) to the sacral spinal cord, which then sends an efferent signal back to the external anal sphincter causing its contraction. A normal response is contraction on both sides, indicating intact sacral pathways and pudendal nerve function. Absence or diminished response points to potential sacral spinal cord injury or pudendal neuropathy, such as in cauda equina syndrome.

In contrast, the abdominal reflex involves stroking the abdomen to elicit abdominal muscle contraction, the cremasteric reflex involves light stimulation of the inner thigh to elevate the testis via the cremaster muscle, and the plantar reflex assesses the corticospinal tract by observing responses on the sole of the foot.