Longitudinal fissure Longitudinal fissure The longitudinal fissure (or cerebral fissure, median longitudinal fissure, or interhemispheric fissure) is the deep groove that separates the two hemispheres of the vertebrate brain. The medial surfaces of the two hemispheres are as similarly convoluted by gyri and sulci as is the outer surface of the brain. It is thought that a majority of existing animals, including Homo sapiens, have evolved from a common wormlike ancestor that lived around 600 million years ago, called the urbilaterian. A bilaterian animal is one that has symmetrical left and right body halves. While it is still debated whether this species
Anal fissure incidence of anal fissures is around 1 in 350 adults. They occur equally commonly in men and women and most often occur in adults aged 15 to 40. Anal fissure An anal fissure, fissure in Ano or rectal fissure is a break or tear in the skin of the anal canal. Anal fissures may be noticed by bright red anal bleeding on toilet paper and undergarments, or sometimes in the toilet. If acute they are painful after defecation, but with chronic fissures, pain intensity is often less. Anal fissures usually extend from the anal opening and are usually located posteriorly