A 27-year-old woman is examined by her gynecologist. Upon rectal examination, a firm structure, directly in front of the rectum in the midline, is palpated through the anterior wall of the rectum. Which is this structure?

The cervix of the uterus is anterior to the rectum. Since the cervix is the inferior pa of the uterus that is protruding into the vagina, it should feel like a firm structure upon palpation. The bladder is the most anterior organ in the pelvis. So, the bladder would not be directly in front of the anterior wall of the rectum. The body of the uterus lies upon the bladder, so it is too far in front of the anterior rectal wall to be palpated. The pubic symphysis is the joint connecting the two pubic bones. It forms the anterior boundary of the pelvis, and would be too far forward to palpate through the rectum. Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 5. Maternal Physiology. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.