Henry Ford Hospital Medical Journal


This study was undertaken to determine if the biped stale of the human female constituted a stress force in urethrovesical physiological function. To arrive at realistic conclusions, the ecomorphologic changes incidental to the conquest of gravity by the vertebrates have been reviewed. Accepting the evolutionary precepts as expressed by Hobart Smith that "if all parts of the evolutionary chain were known, it would be impossible to draw a logical distinction between man and nonman, Romer slated "Bone for bone, muscle for muscle, organ for organ, almost every feature of the ape is repeated in the human body. The differences are almost entirely differences in proportions and relations of parts " Assumption of erect posture by man, as compared to the quadruped, sharply altered urethrovesical relationship. The relative position in the abdominal cavity of the bladder and urethra was changed from a lateral to an inferior position, resulting in an increase in intravesical pressure because the long diameter of the abdominal cavity was oriented vertically. More specifically, the relative position of the urethrovesical function was changed from a lateral to an inferior position when the pressure was the greatest. There is little doubt that this change has played a role in the development of stress urinary incontinence, and there is some evidence to suggest that deficient urethrovesical function to increased gravimetric stress may represent an example of deficient evolutionary adaptation.