Synonyms: Bulbospongiosus reflex (BSR), Osinski reflex
Reflex arc:
a. Stimulus: Briskly squeezing glans penis or clitoris or Tugging Foley’s catheter (pulling the balloon of foley’s catheter against the bladder neck)
b. Afferent: Sensory fibers of pudendal nerve
c. Reflex center: S2-S4 spinal segments (Polysynaptic)
d. Efferent: Motor fibers of pudendal nerve
e. Response: Contraction of Perineal muscles (External Anal Sphincer)
Technique:
- Perform per-rectal examination and evaluate anal tone
- Apply stimulus for BCR to evaluate for increased anal tone
Importance:
1. Normally present in almost all men and 70% women.
2. In spinal cord injury, return of BCR marks the end of spinal shock.
3. It may be preserved in high conus medullaris lesions but it is lost in cauda equina syndrome.
