Summary
The electrical activity of the external anal sphincter and puborectalis muscle of normal subjects has been investigated using concentric needle electrodes.
The activity in these muscles at rest, during voluntary and involuntary contractions and during defecation is described.
The findings show a delicate adjustment of activity to changing needs.
Variations in sphincter tone result from changes in the firing rate of individual motor units and the recruitment of further units.
No indication of different types of muscle fiber or of any “locking” action was found.
Similar content being viewed by others
References
Beck, Adolf: Electromyographische Untersuchungen am Sphincter ani. Arch. ges. Physiol.224: 278, 1930.
Floyd, W. F. and E. W. Walls: Electromyography of the sphincter ani externus in man. J. Physiol.122: 599, 1953.
Frohlich, W. and H. H. Meyer: Untersuchung Uber du Arhonsstrome Anhaltend Verkurzter Muskeln. Abl. Physiol.26: 269, 1912.
Goligher, J. C., A. G. Leacock and J. J. Brossy: The surgical anatomy of the anal canal. Brit. J. Surg.43: 51, 1955.
Thompson, P.: The Myology of the Pelvic Floor. London, McCorquodale, 1899.
Author information
Authors and Affiliations
About this article
Cite this article
Taverner, D., Smiddy, F.G. An electromyographic study of the normal function of the external anal sphincter and pelvic diaphragm. Dis Colon Rectum 2, 153–160 (1959). https://doi.org/10.1007/BF02616708
Issue Date:
DOI: https://doi.org/10.1007/BF02616708