Abstract
Multiport anorectal manometry and external anal sphincter (EAS) and internal anal sphincter (IAS) electromyography were conducted in 15 males (41±3 years) and 20 females (43±2 years; 5 nulliparous) during rest, maximum conscious sphincter contraction, rectal distension and increases in intra-abdominal pressure. The basal pressure declined within 15 minutes of insertion of the manometric probe to a stable plateau, 55±4% of the initial value. The maximum basal (91±5 vs 61±6 cm water; mean±SEM), minimum basal (43±7 vs 27±3 cm water) and the maximum squeeze pressures (257±20 vs 107±13 cm water) were higher (p<0.05) in males than females. Distension of a rectal balloon caused a reduction in pressure in all anal channels, that increased in depth and duration as the distending volume was increased. These anal relaxations were associated with rectal contractions and transient increases in the electrical activity of the EAS. Upon deflating the balloon, the anal pressure increased to values that exceeded the pre-inflation values. The pre-inflation (89±4 vs 49±4 cm water), post-inflation (104±9 vs 62±7 cm water) and residual (47±4 vs 30±2 cm water) pressures during rectal distension were significantly higher in males than in females (p<0.05). The higher residual pressure in males was associated with a higher EAS index during rectal distension (0.94±0.10 vs 0.65±0.10 mv s;p<0.05). The lowest volume required to cause a desire to defaecate was significantly higher in males than in females (76±7 vs 48±6 ml;p<0.05) and only 13% of males compared with 55% females (p<0.01) felt pain during rectal distension with 100 ml. During increases in intra-abdominal pressure, all subjects showed increases in pressures in the outermost anal channels, that were associated with increases in the electrical activity of the EAS and were significantly higher in males compared with females (188±17 vs 98± 9 cm water;p<0.05). In conclusion, the data suggest that males have stronger internal and external anal sphincters than females, while females have greater rectal sensitivity.
Similar content being viewed by others
References
Duthie HL, Bennett RC (1963) The relationship of sensation in the anal canal to the functional anal sphincter; a possible factor in anal incontinence. Gut 4:179–182
Salducci J, Planche D, Naudy B (1982) Physiological role of the Internal Anal Sphincter and the External Anal Sphincter during Miction. In: Weinbeck M (ed) Motility of the Digestive Tract. Raven Press, New York, pp 513–522
Loening-Bauke V, Anuras S (1985) Effects of age and sex on anorectal manometry. Am J Gastroenterol 80:50–53
McHugh SM, Diamant NE (1987) Effects of age, gender and parity on anal canal pressures. Contribution of impaired anal sphincter function to faecal incontinence. Dig Dis Sci 32:726–736
Read NW, Harford WV, Schmulen AC, Read MG, Santa Ana CA, Fordtran JS (1979) A clinical study of patients with faecal incontinence and diarrhoea. Gastroenterology 76:747–756
Bartolo DCC, Read NW, Jarrett JA, Read MG, Donnelly TC, Johnson AG (1983) Differences in anal sphincter function and clinical presentation in patients with pelvic floor descent. Gastroenterology 85:68–75
Basmajian JV, Stecko G (1962) A new bipolar electrode for electromyography. J Appl Physiol 17:849
Haynes WV, Read NW (1982) Anorectal activity in man during rectal infusion of saline. A dynamic assessment of the anal continence mechanism. J Physiol 330:45–56
Monges H, Salducci J, Naudy B, Raniere F, Gonella J, Bouvier M (1980) The electrical activity of the internal anal sphincter: a comparative study in man and cat. In: Christenson J (ed) Gastrointestinal motility. Raven Press, New York, pp 495–501
Freckner B (1975) Function of the anal sphincters in spinal man. Gut 16:638–644
Whitehead WE, Orr WC, Engel BT, Schuster MM (1982) External anal sphincter response to rectal distension: learned response or reflex. Psychophysiology 19:57–72
Freckner B, Ihre T (1976) Influence of autonomic nerves on the internal anal sphincter in man. Gut 17:306–312
Whitehead WE, Schuster MM (1980) Therapeutic applications of biofeedback in gastrointestinal disorder. In: Berk LE (ed) Developments in digestive disease, vol 3. Lea and Febiger, Philadelphia, pp 165–177
Porter NH (1962) Physiological study of the pelvic floor in rectal prolapse. Ann R Coll Surg 31:379–404
Greenwood D, Coggeshall RE, Hulsebosch CE (1985) Sexual dimorphism in the numbers of neurones in the pelvic ganglia of adult rats. Brain Res 14:23–48
Breedlove SM, Arnold AP (1980) Hormone accumulation in a sexually oligomorphic nucleus of the rat spinal cord. Science 210:564–566
Fielding JF (1977) The irritable bowel syndrome. Clin Gastroenterol 6:607–622
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sun, W.M., Read, N.W. Anorectal function in normal human subjects: Effect of gender. Int J Colorect Dis 4, 188–196 (1989). https://doi.org/10.1007/BF01649702
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01649702