• Strong, repeated shear force in the anal canal is likely to permanently damage supporting tissues of the internal hemorrhoidal cushions at the least, leading to internal hemorrhoidal prolapse. Since healthy internal and external anal cushions help to maintain fecal continence with a watertight seal, anal canal deformation due to their disease or removal can result in fecal incontinence.
• Internal rectal prolapse (IRP), aka rectal intussusception, is a common finding among asymptomatic individuals. Strong, repeated shear force in the rectum probably does contribute to development of full-thickness external rectal prolapse (aka procidentia) particularly when IRP is present. Conditions such as internal hemorrhoidal prolapse also may contribute to rectal prolapse development, and fecal incontinence can be a consequence of rectal prolapse as well.
• Overstretching the anal canal with girthy insertions is likely to cause disruption or fragmentation of one or both anal sphincter muscles, which results in permanent muscle weakening and is associated with fecal incontinence (especially with a damaged or dysfunctional puborectalis muscle). Stretching the anal canal repeatedly with insertions of progressively increasing circumference may cause cumulative muscle damage.
• Trauma—including erotic anoreceptive trauma—can instigate development of numerous other anorectal conditions that may cause or lead to fecal incontinence, including fistulas. Surgical treatments for anorectal conditions also can contribute to development of fecal incontinence.