A radiographic study of the development of the skeleton of the foetal pig

Abstract

SUMMARYA radiographic study was made of the skeleton of eighty-three foetuses from twenty-four litters killed between the 37th and 112th day of gestation. Measurements were taken, from radiographs, of the length and depth of the skull and the length of the diaphyses of the humerus, radius, ulna, metacarpus, ilium, ischium, femur, tibia, fibula, calcaneum and metatarsus. Skull length, humerus and metatarsus were selected for statistical analysis. The litter mean lengths of the diaphyses were studied in relation to age, weight, and age and weight jointly. Within-litter differences in bone measure-ments were closely associated with foetal weight differences.The relationships of litter mean log. lengths of the skull, humerus and metatarsus upon age were best fitted by a quadratic regression, and with mean log. foetal weight by linear function regressions. A joint regression incorporating both age and weight of the foetuses fitted the data significantly better than equations based on weight or age alone. Skull length was found to have a growth coefficient between the 51st and 112th day of gestation significantly lower than that of the other bones examined. The age at which the primary and secondary ossification centres appear was studied.