Later, the mass may have to be pushed back in following defecation. This may progress to a chronically prolapsed and severe condition, defined as spontaneous prolapse that is difficult to keep inside, and occurs with walking, prolonged standing, coughing or sneezing (Valsalva maneuvers). A chronically prolapsed rectal tissue may undergo pathological changes such as thickening, ulceration and bleeding.If the prolapse becomes trapped externally outside the anal sphincters, it may become strangulated and there is a risk of perforation. This may require an urgent surgical operation if the prolapse cannot be manually reduced. Applying granulated sugar on the exposed rectal tissue can reduce the edema (swelling) and facilitate this. Cause
The precise cause is unknown, and has been much debated. In 1912 Moschcowitz proposed that rectal prolapse was a sliding hernia through a pelvic fascial defect.This theory was based on the observation that rectal prolapse patients have a mobile and unsupported pelvic floor, and a hernia sac of peritoneum from the Pouch of Douglas and rectal wall can be seen. Other adjacent structures can sometimes be seen in addition to the rectal prolapse. Although a pouch of Douglas hernia, originating in the cul de sac of Douglas, may protrude from the anus (via the anterior rectal wall), this is a different situation from rectal prolapse. Shortly after the invention of defecography, In 1968 Broden and Snellman used cinedefecography to show that rectal prolapse begins as a circumferential intussusception of the rectum, which slowly increases over time.
Darwins tubercle (or auricular tubercle) is a congenital ear condition which often presents as a thickening on the helix at the junction of the upper and middle thirds. History
This atavistic feature is so called because its description was first published by Charles Darwin in the opening pages of The Descent of Man, and Selection in Relation to Sex, as evidence of a vestigial feature indicating common ancestry among primates which have pointy ears. However, Darwin himself named it the Woolnerian tip, after Thomas Woolner, a British sculptor who had depicted it in one of his sculptures and had first theorised that it was an atavistic feature. Prevalence
The feature is present in approximately 10.4% of the Spanish adult population, 40% of adults in India, and 58% of Swedish school children. This acuminate nodule represents the point of the mammalian ear. The trait can potentially be bilateral, meaning present on both ears, or unilateral, where it is present on only one ear. There is mixed evidence in regard to whether the bilateral or unilateral expression is related to population, or other factors. Some populations express full bilateral, while others may express either unilateral or bilateral. However, bilateral appears to be more common than unilateral as it pertains to the expression of the trait. Inheritance
The gene for Darwins tubercle was once thought to be inherited in an autosomal dominant pattern with incomplete penetrance, meaning that those who possess the allele (version of a gene) will not necessarily present with the phenotype.