Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Anal reflex versus bulbocavernosus reflex in evaluation of patients with spinal cord injury


The examination of sacral reflexes provides an important method to differentiate an upper motor neuron vs lower motor neuron spinal cord injury (SCI). Two common sacral mediated reflexes used as part of the neurological assessment include the bulbocavernosus reflex (BCR) and anal reflex. As the clinical information from these tests are similar, we suggest that the anal reflex provides a better first option as a non-invasive clinical assessment of sacral reflex status in clinical practice in SCI as the testing for the anal reflex is less intrusive and already being performed as part of the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) by pinprick stimulation of the S4–5 dermatome.

This is a preview of subscription content

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Elicitation of bulbocavernosus reflex.
Fig. 2: Elicitation of anal reflex.


  1. 1.

    Uher EM, Swash M. Sacral reflexes: physiology and clinical application. Dis Colon Rectum. 1998;41:1165–77.

    CAS  Article  Google Scholar 

  2. 2.

    American Spinal Injury Association/ International Medical Society of Paraplegia. International standards for neurological and functional classification of spinal cord injury patients. 7th ed. Chicago, Illinois: ASIA; 2015.

  3. 3.

    Krassioukov A, Biering-Sorensen F, Donovan W, Kennelly M, Kirshblum S, Krogh K, et al. International standards to document remaining autonomic function after spinal cord injury. J Spinal Cord Med. 2012;35:201–10.

    Article  Google Scholar 

  4. 4.

    Previnaire JG. The importance of the bulbocavernosus reflex. Spinal Cord Ser Cases. 2018;4:2.

    Article  Google Scholar 

  5. 5.

    Alexander M, Aslam H, Marino RJ. Pulse article: how do you do the international standards for neurological classification of SCI anorectal exam? Spinal Cord Ser Cases. 2017;3:17078.

    Article  Google Scholar 

  6. 6.

    Doherty JG, Burns AS, O’Ferrall DM, Ditunno JF. Prevalence of upper motor neuron vs lower motor neuron lesions in complete lower thoracic and lumbar spinal cord injuries. J Spinal Cord Med. 2002;25:289–92.

    Article  Google Scholar 

  7. 7.

    Burns AS, Rivas DA, Ditunno JF. The management of neurogenic bladder and sexual dysfunction after spinal cord injury. Spine. 2001;26 Suppl 24:S129–36.

    Article  Google Scholar 

  8. 8.

    Clinical practice guidelines: neurogenic bowel management in adults with spinal cord injury. Spinal cord medicine consortium. J Spinal Cord Med. 1998;21:248–93.

  9. 9.

    Previnaire JG, Soler JM, Alexander MS, Courtois F, Elliott S, McLain A. Prediction of sexual function following spinal cord injury: a case series. Spinal Cord Ser Cases. 2017;3:17096.

    CAS  Article  Google Scholar 

  10. 10.

    Stiens SA, Bergman SB, Goetz LL. Neurogenic bowel dysfunction after spinal cord injury: clinical evaluation and rehabilitative management. Arch Phys Med Rehabil. 1997;78:S86–102.

    CAS  Article  Google Scholar 

  11. 11.

    Alexander MS, Marson L. The neurologic control of arousal and orgasm with specific attention to spinal cord lesions: integrating preclinical and clinical sciences. Auton Neurosci. 2018;209:90–99.

    Article  Google Scholar 

  12. 12.

    Wester C, FitzGerald MP, Brubaker L, Welgoss J, Benson JT. Validation of the clinical bulbocavernosus reflex. Neurourol Urodyn. 2003;22:589–91.

    CAS  Article  Google Scholar 

  13. 13.

    Wyndaele JJ. Correlation between clinical neurological data and urodynamic function in spinal cord injured patients. Spinal Cord. 1997;35:213–6.

    CAS  Article  Google Scholar 

  14. 14.

    Bors E, Blinn KA. Bulbocavernosus reflex. J Urol. 1959;82:128–30.

    CAS  Article  Google Scholar 

  15. 15.

    Campbell WW. The deep tendon or muscle stretch reflexes. In: Dejong’s The Neurologic Examination. 7th ed. Philadelphia: Kluwer Walters; 2013. p. 561–78.

  16. 16.

    Podnar S. Saddle sensation is preserved in a few patients with cauda equina or conus medullaris lesions. Eur J Neurol. 2007;14:48–53.

    CAS  Article  Google Scholar 

  17. 17.

    Vivek P. Acute spinal cord injury. In: Manipal manual of orthopaedics. 1st ed. London: Jaypee Brothers Medical; 2019. p. 110.

  18. 18.

    Blaivas JG, Zayed AAH, Labib KB. The bulbocavernosus reflex in urology: a prospective study of 299 patients. J Urol. 1981;126:197–9.

    CAS  Article  Google Scholar 

  19. 19.

    Chancellor MB, Blaivas JG. Neuro-urologic examination. In: Chancellor MB, Blavias JG, editors. Practical neuro-urology: genitourinary complications in neurologic disease. Boston, Oxford: Butterworth-Heinemann; 1995. p. 55–62.

  20. 20.

    Stanton SL. History and examination. In: Stanton SL, Monga AK, editors. Clinical urogynecology. 2nd ed. London: Churchill Livingstone; 2000. p. 77–84.

  21. 21.

    Khullar V, Cardozo L. History and examination. In: Cardozo L, Staskin D, editors. Textbook of female urology and urogynecology. United Kingdom: Taylor and Francis; 2001. p. 153–65.

  22. 22.

    Granata G, Padua L, Rossi F, De Franco P, Coraci D, Rossi V. Electrophysiological study of the bulbocavernosus reflex: normative data. Funct Neurol. 2013;28:293–5.

    PubMed  Google Scholar 

  23. 23.

    Hargrove GK, Bors E. The suprapubic abdominal tap reflex: a useful method to assess the function of the sacral reflex arcs. J Urol. 1972;107:243–4.

    CAS  Article  Google Scholar 

  24. 24.

    Cohen JM, Novick AK. Spinal cord injury rehabilitation and the ICU. In: Layon JA, Gabrielli A, Friedman WA, editors. Textbook of neurointensive care. 2nd ed. London: Springer; 2013. p. 676.

  25. 25.

    Vodušek DB. Neural control of pelvic floor muscles. In: Pelvic floor re-education. London: Springer London; 2008. p. 22–35.

  26. 26.

    Lapides J, Bobbitt JM. Diagnostic value of bulbocavernous reflex. J Am Med Assoc. 1956;162:971–2.

    Article  Google Scholar 

  27. 27.

    Ko HY, Ditunno JF, Graziani V, Little JW. The pattern of reflex recovery during spinal shock. Spinal Cord 1999;37:402–9.

    CAS  Article  Google Scholar 

  28. 28.

    Ko HY. Revisit spinal shock: pattern of reflex evolution during spinal Shock. Korean J Neurotrauma. 2018;14:47–54.

    Article  Google Scholar 

  29. 29.

    Yang CC, Bradley WE. Reflex innervation of the bulbocavernosus muscle. BJU Int. 2000;85:857–63.

    CAS  Article  Google Scholar 

  30. 30.

    Smith RP, Turek PJ. The Netter collection of medical iilustrations. Volume 1. In: Reproductive system. 2nd ed. Philadelphia, PA: Elsevier; 2011. p. 30

  31. 31.

    Rossolimo G. Der Analreflex, seine Physiologie und Pathologie. Neurol Cent. 1891;4:257–9.

    Google Scholar 

  32. 32.

    Pedersen E, Harving H, Klemar B, Torring J. Human anal reflexes. J Neurol Neurosurg Psychiatry. 1978;41:813–8.

    CAS  Article  Google Scholar 

  33. 33.

    Alexander MS, Carr C, Chen Y, McLain A. The use of the neurologic exam to predict awareness and control of lower urinary tract function post SCI. Spinal Cord. 2017;55:840–3.

    CAS  Article  Google Scholar 

  34. 34.

    Sanders C, Driver CP, Rickwood AMK. The anocutaneous reflex and urinary continence in children with myelomeningocele. BJU Int. 2002;89:720–1.

    CAS  Article  Google Scholar 

  35. 35.

    Bartolo DCC, Jarratt JA, Read NW. The cutaneo-anal reflex: a useful index of neuropathy? Br J Surg. 1983;70:660–3.

    CAS  Article  Google Scholar 

  36. 36.

    Sinnatamby CS. Introduction to regional anatomy. In: Last’s Anatomy. 12th ed. London: Elsevier; 2011. p. 28–9.

  37. 37.

    Swash M. Early and late components in the human anal reflex. J Neurol Neurosurg Psychiatry. 1982;45:767–9.

    CAS  Article  Google Scholar 

  38. 38.

    Roberts MM. Neurophysiology in neurourology. Muscle Nerve. 2008;38:815–36.

    Article  Google Scholar 

  39. 39.

    Campbell WW. The superficial (cutaneous) reflexes. In: Dejong’s the neurologic examination. 7th ed. Philadelphia: Wolters Kluwer; 2013. p. 581.

  40. 40.

    Rodriguez G, King JC, Stiens S. Neurogenic bowel: dysfunction and rehabilitation. In: Braddom RL, Chan L, Harrast MA, editors. Physical medicine and rehabilitation. 4th ed. Philadelphia, PA: Saunders/Elsevier; 2011. p. 630.

  41. 41.

    Shiers S, Singal A, Korsten MA. Gastrointestinal system after spinal cord injury: assessment and intervention. In: Lin VW, Bono CM, editors. Spinal cord medicine, seconnd edition: Principles & Practice. 2nd ed. New York: Demos Medical; 2010. p. 395.

  42. 42.

    King JC, Currie DM, Wright E. Bowel training in spina bifida: importance of education, patient compliance, age, and anal reflexes. Arch Phys Med Rehabil. 1994;75:243–7.

    CAS  Article  Google Scholar 

  43. 43.

    Dhatt S, Tahasildar N, Tripathy SK, Bahadur R, Dhillon M. Outcome of spinal decompression in cauda equina syndrome presenting late in developing countries: case series of 50 cases. Eur Spine J. 2011;20:2235–9.

    Article  Google Scholar 

  44. 44.

    Donovan WH. The importance of the anal exam in neurologic classification of spinal cord injury. Spinal Cord Ser Cases. 2018;4:4.

    Article  Google Scholar 

  45. 45.

    Uff CE. Clinical assessment of cauda equina syndrome and the bulbocavernosus reflex (letter).

  46. 46.

    Podnar S. Clinical elicitation of the penilo-cavernosus reflex in circumcised men. BJU Int. 2012;109:582–5.

    Article  Google Scholar 

  47. 47.

    Lavy C, James A, Wilson-MacDonald J, Fairbank J. Cauda equina syndrome. BMJ 2009;338:b936.

    Article  Google Scholar 

  48. 48.

    Ertekin C, Reel F. Bulbocavernosus reflex in normal men and in patients with neurogenic bladder and/or impotence. J Neurol Sci. 1976;28:1–15.

    CAS  Article  Google Scholar 

  49. 49.

    Niu X, Wang X, Ni P, Huang H, Zhang Y, Lin Y, et al. Bulbocavernosus reflex and pudendal nerve somatosensory evoked potential are valuable for the diagnosis of cauda equina syndrome in male patients. Int J Clin Exp Med. 2015;8:1162–7.

  50. 50.

    Lee DG, Kwak SG, Chang MC. Prediction of the outcome of bladder dysfunction based on electrically induced reflex findings in patients with cauda equina syndrome: a retrospective study. Medicine. 2017;96:e7014.

    Article  Google Scholar 

  51. 51.

    Marino RJ. The anorectal exam is unnecessary! Spinal Cord Ser Cases. 2018;4:3.

    Article  Google Scholar 

Download references


We thank to Jason Bitterman MD for his figures drawn for this paper.


This study was supported in part a grant from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR grant number 90SI5026).

Author information



Corresponding author

Correspondence to Steven Kirshblum.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kirshblum, S., Eren, F. Anal reflex versus bulbocavernosus reflex in evaluation of patients with spinal cord injury. Spinal Cord Ser Cases 6, 2 (2020).

Download citation

Further reading


Quick links