Abstract
Using 210 autopsy cases of newborn infants, the degree of development of gastric muscle layer was studied stepwise pathomorphologically. Furthemore, using 6 cases of gastric rupture in newborn infants, the cause of rupture was studied and the following conclusions were obtained.
1. The gastric muscle layer differentiated and develops in proportion to the week of fetal life. The circular muscle layer reaches the standard growth level at the 37 th week of fetal life, while the longitudinal muscle layer develops similary in the 29 th week.
2. As to the site, the best development was achived in the pylorus, followed by the corpus, and fundus, with no difference between the greater and lesser curvature
3. In the gastric muscle layer of the newborn infants, the site of physiological lack of circular muscle layer was demonstrated. The presence of thin portion was also confirmed.
4. As to the correlation of 3 factors, longitudinal muscles, oblique muscles and thinning on this fissure, 8 types of fissures could be distinguished.
5. Among the 8 types, the fissure with lack of longitudinal and oblique muscle with thinning appears to be the most dangerous portion in the newborn stomach.
6. Such a portion occupies 18.6% of the ruptured fissure, 20 times as high as than in the non-ruptured cases.
These results would indicate that such a dangerous portion is prone to rupture by the action of some factors even if such a defect is not the direct cause of the rupture.
