Linear growth and appearance of sex difference in the rabbit pelvis



Roentgenograms of the pelves of a population of rabbits were secured once each week between 15 and 92 days after birth and once every two weeks thereafter to 204 days. Measurements were made of projections of certain pelvic dimensions on the roentgenograms.

With one exception (pelvis width, day 36), no significant differences at the 1% level between males and females were found in os coxae length, ilium length, pelvis width and bi-ischial width. However, interacetabular width of the female became significantly greater than that of the male by day 57.

Mean measurements of all dimensions showed characteristic rates of increase with age. Nine-tenths of total increase in lengths of os coxae and ilium occurred by 106 days; pelvis width, by 120 days; bi-ischial and interacetabular width each, by about 148 days.

Between 35 mm to 105 mm of tibia length taken as a basis of reference, all dimensions studied showed approximately straight line relative growth trends.

Variation in measurements was relatively high, with greatest variation in all except bi-ischial width tending to occur before 50 days, when growth was most rapid. It was lowest in the period 64 to 120 days.