Pathology of the foregut
In the lower foregut region fistulas, stenosis and ectopic tissue also form the main class of the abnormalities.
Abnormalities in the esophagus region
The most frequent disorders such as fistulas or atresias of the esophagus are associated with abnormalities of the developing respiratory tract.
Other, more seldom abnormalities such as stenosis of the esophagus result from a missing recanalization during development. Both with atresias and with stenosis of the esophagus the fetus cannot swallow and thus reabsorb amniotic fluid, a situation leading to a polyhydramnion.
The pyloric stenosis arises through a hyperplasia of the pyloric sphincter muscle and is a relatively frequent disorder, mainly in male newborns. It leads to sudden and convulsive vomiting and can be rectified by a longitudinal incision of the pyloric sphincter muscle.
Stenosis as well as atresias can also occur in the small intestine. As in the esophagus they are based on an absent recanalization of the lumen. Such disorders are nevertheless very seldom.