The bulbocavernous reflex (BCR) is a clinical test of the autonomic nervous system. It involves the contraction of the bulbocavernosus muscle, which is located in the perineal region, in response to stimulation of the anal sphincter. The purpose of the BCR is to evaluate the integrity of the pudendal nerve, as well as to identify neurological disorders such as multiple sclerosis and spinal cord injury.

The BCR is typically assessed by applying a single finger to the anal sphincter, which then induces a contraction of the bulbocavernosus muscle. The contraction is assessed through palpation of the muscle and can be graded according to the degree of contraction. A normal BCR response is considered to be a Grade 3 contraction, which is defined as a visible contraction of the muscle that can be felt on palpation.

The BCR is considered to be a useful clinical test for assessing the integrity of the pudendal nerve and for identifying neurological disorders. It is important to note, however, that the BCR is not a definitive diagnostic tool and should be used in conjunction with other tests for a more comprehensive evaluation.


Klug, H., & Radziszewski, P. (2018). Bulbocavernosus reflex: A review of the evidence. World Journal of Urology, 36(6), 873–881. https://doi.org/10.1007/s00345-018-2238-9

Stein, S., Pudendal nerve dysfunction and the bulbocavernosus reflex. Urology, 52(4), 674-678. https://doi.org/10.1016/S0090-4295(98)00235-6

Türk, C., & Jonas, U. (2008). Clinical significance of bulbocavernosus reflex. European Urology, 54(1), 16–20. https://doi.org/10.1016/j.eururo.2008.02.041

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