In addition to the enteric nervous system, the interstitial cells of Cajal and the smooth musculature, the collagenous fibre network of the muscularis propria plays a major role in the coordination of peristalsis. Partial or complete absence of this network in patients with chronic constipation has been described as 'desmosis'. Two major subtypes of desmosis can be distinguished: in the rare congenital (primary) aplastic desmosis of childhood, the collagenous fibre network is not formed. This is characteristic of microcolon megacystis syndrome and is associated with aperistalsis. The more common atrophic (secondary) desmosis of adulthood is typically incomplete and associated with a hypoperistaltic syndrome. Neither the etiology nor the pathogenesis of desmosis are currently understood. Atrophic desmosis may occur after previous inflammatory episodes. Further extensive studies are needed to better understand the pathogenesis, etiology and functional implications of this disease.