16 March, 2018
Anatomy Associated With a Cesarean Section
Taking an unborn child from the mother's womb through surgical means goes far back in history, with references in western and non-western mythology and lore. Early cesarean operations were performed only on dead or dying women. A better understanding of anatomy, the importance of cleanliness during surgery and the arrival of anesthesia made successful cesarean sections possible, saving both mother and child, by the end of the 1800s. In 2008, cesarean procedures or C-sections comprised 32.3 percent of deliveries.
General Anatomical Picture
Normally the orange-sized uterus occupies a space in the lower abdominal cavity. During pregnancy, it grows to the size of a watermelon at full term. It is cradled by the bones of the pelvis and supported by the muscles of the abdominal wall. The growing uterus pushes aside other abdominal organs. The liver, spleen and stomach move toward the top of the abdominal cavity. The small intestines get displaced upward and to the sides and back of the uterus. The bladder maintains its position below and in front of the lowest portion of the uterus. At full term, the uterus fills the abdominal cavity below the abdominal wall from the pubic area to the bottom of the rib cage.
Getting Through the Abdominal Wall
To begin a C-section, the surgeon makes incisions through the layers of the abdominal wall. The first layer is the skin, underlain by subcutaneous tissues, connective tissue called fascia and muscles. Then comes the lining of the abdominal cavity, called the peritoneum, which encloses all the abdominal contents. The uterus lies right below the peritoneum. Since blood supply to the uterus greatly increases during pregnancy, surgeons take into account blood vessel positions and their increased blood flow to avoid hemorrhage. The uterine artery branches several times to supply blood to all areas of the uterus plus the vagina and cervix. The bumps of the hipbones, or anterior superior iliac crests, provide landmarks for incision placements.
Three layers of muscle make up the uterine wall. To reach the baby, either a transverse or vertical incision is made through the uterine wall, taking care toward the bottom of the incision not to injure the baby, umbilical cord or placenta. The transverse incision may allow future normal vaginal deliveries, while the vertical incision produces a weaker scar and increases the chance for repeat cesarean sections during later pregnancies. Once the uterine wall is open, the surface of the amniotic sac that encloses the baby is visible.
Delivering the Baby
To deliver the baby, the surgeon opens the amniotic sac and suctions out the amniotic fluid that surrounds the baby. During normal delivery, the amniotic sac usually breaks early in the process, and when the fluid gushes out it's called water breaking. After gently extracting the baby, a doctor or nurse cleans its nose and mouth. The umbilical cord attaches the baby from its navel to the placenta, the spongy organ that joins to part of the interior uterine wall to connect the mother's blood system and the baby's. The surgeon clamps the cord and cuts it. Then the placenta, also called the afterbirth, separates from the uterine wall and is removed. The doctor flushes clean the now-empty uterus and closes the incisions with sutures.
- National Institutes of Health: U.S. National Library of Medicine: History of Medicine: Cesarean Section--A Brief History
- American Academy of Family Physicians: Chapter Q Cesarean Delivery
- American Pregnancy Association: Uterus Size During Pregnancy
- University of Maryland Medical Center: C-section
- Encyclopedia of Surgery: Cesarean Section
- Mayo Clinic: Labor and Delivery, Postpartum Care: Water Breaking: Understand This Sign of Labor
- Childbirth Connection: Your Growing Body & Baby: Pictures
- Ablestock.com/AbleStock.com/Getty Images