Sex differences in the growth of the human bony pelvis

The study of individual patterns of longitudinal growth of the bony pelvic complex reveals the following findings concerning the sex differences in the growth of the bony pelvis. (1) The patterns of growth show the same individual variability and male-female overlap as the adult configuration of pelves. (2) The sex differences in the adult bony pelvis cannot be attributed to the differential response of one bone to sex hormone. (3) Sex differences develop from complicated variations in rates and direction of growth of local areas of the pelvic complex. (4) The superior functional division of the bony pelvis shows only one notable sex difference — the sexual dimorphism of the directional growth of the anterior one-half of the iliac crest. (5) The inferior functional division of the bony pelvis shows numerous local areas of sexually dimorphic growth, but the major sex differences result from the greater lateral migration of the ischia. (6) Of the regions showing definite sexual dimorphism in growth, the pelvic inlet and sciatic notch are the more variable because of their dependency on two separate anatomical systems for their final adult morphological configuration. The subpubic angle and length of the superior pubic ramus are directly associated with only one anatomical system, the enlargement of the pelvic cavity, thus, they show less variability and more definitive sex difference.