Certified Rehabilitation Registered Nurse (CRRN) Practice Exam

Which spinal segments must be preserved for reflexogenic erections to occur?

1. Cervical

2. Thoracic

3. Lumbar

4. Sacral

The correct answer is: Sacral

Reflexogenic erections are those that occur in response to sensory stimulation, and their physiological basis primarily involves specific spinal cord segments. The sacral spinal segment, particularly the neural pathways originating at S2 to S4, plays a crucial role in the mechanism of erection. This area houses the preganglionic parasympathetic neurons which, when stimulated, lead to engorgement of the penile tissues, facilitating the erection process. Preserving these sacral segments is essential for allowing the reflex arc that leads to an erection when there is appropriate physical stimulation. In neurological conditions or injuries where the sacral segments have been compromised, reflexogenic erections are unlikely to occur, demonstrating the vital role these segments play in erectile function.