The anal cushions are composed or erectile tissue similar to that in the penis. This is developed to enormous size in some gibbons and mandrills, where it is a sexual signal, but in man it’s more modest function is to seal the anal canal and prevent seepage. We showed that haemorrhoids are associated with hypertension of the anal cushions probably caused by an imbalance of the autonomic control of the pre and post erectile sphincters. Does anybody know if Viagra causes haemorrhoids?

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  2. Sun, W.M., Read, N.W., Shorthouse, A.J. (1990) The hypertensive anal cushion as a causse of high anal canal pressures in patients with haemorrhoids. Brit. J. Surg. 77: 458-462.
  3. Sun, W.M., Peck, R.J., Shorthouse, A.J., Read, N.W. (1992) Haemorrhoids are associated not with hypertrophy of the internal anal sphincter but with hypertension of the anal cushions. Br. J. Surg. 79: 592-594