1. Congenital Malformations

There may be abnormal smallness-either with or without other more general malformations. Sometimes an Hour-glass form is presented on account of the middle part of the stomach being contracted. But this malformation may be acquired by cicatricial contraction.

Atresia and stenosis of the pylorus are met with as congenital conditions. Atresia or complete occlusion occurs in the form either of a simple diaphragm between stomach and duodenum (similar diaphragms may occur at other parts of the stomach), or as a more complete separation, there being only a cord uniting stomach and duodenum. Congenital stenosis of the pylorus is alleged to be of frequent occurrence. According to Maier there are two forms, a funnel-shaped and ring-shaped. In the former the pyloric portion of the stomach is converted chiefly by hypertrophy of the muscular coat, into a somewhat rigid funnel, whose apex projects into the loose duodenum. The condition is compared to that of the normal cervix uteri in its relation to the loose vagina. Tilger describes a case in which the stenosis extended to the first part of the duodenum. In the ring-shaped form there is an abrupt narrow projecting ring, formed by localized thickening of the muscular coat. The congenital stenosis is often associated with fixation of the pylorus due to a dense and thick hepatico-duodenal ligament. Congenital stenosis like the acquired forms will be followed by dilatation of the stomach sometimes associated with hypertrophy of the muscular coat. Care is required in diagnosing congenital stenosis, as various states of contraction of the muscular coat in the pyloric region may simulate it, and it may also be simulated by thickening due to chronic catarrh.