Inside Your Tummy: Abdominal Wall Anatomy
Do you know what makes a tummy healthy? Pregnancy and body weight fluctuations can cause some interesting changes to your abdomen. Often, this weakens important abdominal structures, which can make the belly appear flabby and distended. Learning about the different parts of your abdominal wall can help you understand which areas can be treated with exercise and cosmetic surgery to improve the health and attractiveness of your tummy.
The anatomy of your abdominal wall has many parts. Each serves an important function to give your abdomen the structure, strength, and protection it needs to look fit and work properly. Understanding the anatomy of your abdominal wall can benefit patients who are considering a tummy tuck or mummy makeover, and also women who want to to treat abdominal muscle separation with exercise or surgery.
Layers of the abdominal wall
- Structures above the abdominal muscles
- Abdominal and core muscles
- Structures below the core muscles
Most people think of the tummy as superficial. The truth is that the abdomen has a lot more going on than you might expect. There are several layers that make up your abdominal wall. This includes the skin, the Camper’s fascia, Scarpa fascia, four groups of abdominal muscles, the transversalis fascia, connective tissue, and peritoneum.
Structures above the abdominal muscles
The uppermost or superficial layer of your abdomen contains the skin, subcutaneous tissue, two layers of fascia (Scarpa’s fascia and Camper’s fascia), and also connective tissue. This part of the tummy gives structure and protection to your internal organs. Nerves, lymphatics, and blood vessels are also present throughout.
Skin quality is an important indicator of health and youthfulness. Strong, healthy abdominal skin is firm and elastic. Unfortunately, it is rather easy to stretch the skin on your belly. The older you get, the easier it is to damage the skin because mature skin does not bounce back as easily as it once did.
Gaining weight or having a baby can also take a toll on skin. As the body stretches to accommodate either underlying fat or a growing fetus, it can weaken the skin structure dramatically. The skin may develop a loose, sagging appearance, creases, and folds. Stretch marks are another common problem.
Stretched skin does not always shrink back to how it was before. Rather than seeing a nice, trim tummy after losing weight or having a baby, the skin can seem to simply hang loose from the tummy. Women with multiple pregnancies and patients who have undergone bariatric or gastric bypass surgery are most at risk. People over age 30 are also affected because skin produces progressively less collagen and elastin as the body ages.1,5
There are many ways to treat skin aging and stretch marks. Lots of over-the-counter beauty products, home remedies, and prescriptions promise to make the skin appear youthful. However, when you have damaged abdominal skin, there are usually other underlying problems that need to be addressed as well. Plastic surgery can help improve the appearance of abdominal skin, remove fat, and repair stretched or torn abdominal muscles at the same time.
It is important to mention that cosmetic surgery does not change the biology of the skin. If your skin is aged, inelastic, or lacking collagen, a tummy tuck won’t magically make your skin inherently youthful again. No surgeon can promise that with body contouring surgery.
However, a tummy tuck can help your skin appear younger since the skin is pulled nice and taut when the incision is closed with sutures. This gives the skin a firmer appearance, even though the skin is not structurally different than it was before surgery. Abdominoplasty may also remove some stretch marks on the tummy when the skin is trimmed.
The layer just below the skin is called subcutaneous tissue. It is also known as the hypodermis. From regulating body temperature to blood flow, this tissue serves many important functions. It is made up of fat and connective tissue. Blood vessels and nerves run through this layer, which acts as a passageway for blood flow between the upper layers of skin and underlying muscle.
Below the skin are two layers of superficial fascia. The Camper’s fascia is the first layer. The fascia of Camper contains mostly areolar tissue, which is made of elastic and smooth connective fibers with a minimal amount of fat.
There are six types of connective tissue in the human body. Areolar tissue is a loose connective tissue made from a meshwork of collagen fibers and elastic tissue. One function of areolar tissue is to connect the skin to the muscles below. Areolar tissue helps give the abdomen structure so that everything stays in its proper place. It also stores some fat and helps insulate the body.
Adipose tissue (fat)
Fat, or adipose tissue, is a special kind of connective tissue made of adipocytes. The purpose of these cells is to store energy from food. Food fuels adipose tissue with calories, which gives us energy. That’s why when you workout, you burn fat. Yet even when you sit still or sleep, your body is always burning calories. Whether you are digesting food, breathing, or blinking your eyes, the human body is always doing something that requires energy. Adipose tissue also cushions and insulates the body.
Too much subcutaneous fat can leave your tummy soft and pudgy. When we think of getting a tummy tuck with liposuction or VASER liposculpture, it’s often this layer of connective tissue that we want to address. Pregnancy, aging, medications, eating too many high-calorie foods without working out, and even your body’s unique biochemistry can lead to a buildup of adipose tissue.
The tummy is often the first place people gain weight. Lipo-abdominoplasty surgery is an excellent way to remove belly fat, even the stubborn kind that exercise and diet alone don’t seem to help.
The Scarpa fascia is located beneath the Camper’s fascia in your abdomen. It is a thick, membraneous layer on the anterior abdominal wall.
The Scarpa fascia is a very important part of successful tummy tuck surgery. This is the structure that gets sutured closed in abdominoplasty. It is very strong and tough, so it can support a lot of tension. That allows your surgeon to get a nice, taut closure of the incision without compromising skin vascularity.2
The way your surgeon dissects in or around the Scarpa fascia can mean the difference between a surgery with or without drains. Most patients find drains to be a real pain. Drains are rather inconvenient and cumbersome. By operating carefully in and around the scarpa fascia, a tummy tuck without drains is possible. Unfortunately, some tummy tuck surgeons today still use drains because they are not trained on the latest techniques. You can save yourself the hassle of having to use drains by choosing a surgeon who knows how to perform drainless abdominoplasty.
Preserving the Scarpa fascia is important during abdominoplasty to give patients the best results. By dissecting superficially and taking care to avoid damaging the blood supply to the Scarpa’s fascia, Doctor Bernard Beldholm can avoid using drains entirely. This means an easier recovery for his patients.
Abdominal and core muscles
Your body core includes all of the muscles located in your midsection, including those found on the front, back, and sides. These muscles work together to give you body proper alignment, mobility, strength, and the ability to bear weight. The abdominal and pelvic floor muscles work in tandem to keep you pain free. A weak body core can cause all sorts of problems, including pain. You can read more information about your body core here.
Inside your abdomen are some very important muscle groups. There are four layers of abdominal muscles that we will talk about today:
Rectus abdominis muscles, aka “six-pack” abs
The most commonly known abdominal muscle group is the rectus abdominis. These are best known as the “six-pack” muscles. This is the most superficial abdominal muscle group because it lies closest to your skin. You can see these muscles very clearly in a person with a muscular physique.
The rectus abdominis is a flat muscle made of layers that form a fibrous sheath. The fibrous bands that divide the abs into the small, rectangular sections that you see on a toned tummy are called tendinous intersections.
The rectus abdominis is also divided down the middle of your tummy. This gives the rectus the appearance of having two sides, located vertically on either side of your belly button. A tough, fibrous structure known as the linea alba joins them at the midline. The linea alba is rather elastic, and for good reason. It helps support the internal abdominal stress that is created when you move.3 Whether you are lifting, pulling, twisting, or bending, the linea alba adjusts to accommodate your body’s many incredible movements using a network of elastic fibers.
The linea alba also stretches during pregnancy. As the baby grows, the tummy enlarges and the linea alba must stretch to make room for the growing baby. Unfortunately, it can only stretch so much before it tears. And once it stretches, it may not go back to how it was before pregnancy.
Known as diastasis recti, abdominal muscle separation is a condition that is very common among pregnant women. It can cause belly bulge, back and pelvic pain, urine leaking, and a visible gap between the rectus muscles on the tummy. Abdominal muscle separation is a leading reason women get cosmetic surgery after giving birth. Straining, poor posture, and lifting heavy weights can also stretch or tear the rectus and connecting membrane. Dr Bernard Beldholm talks in more detail about diastasis recti here.
The muscles do not always go back to how they were before pregnancy. Core exercises can help prevent and treat muscle separation, but for some patients the damage may be beyond the help of exercise alone. A tummy tuck can repair diastasis recti caused by pregnancy. During surgery, Dr. Bernard uses sutures to bring the muscles back to their original position. This gives the tummy a healthy, normal appearance once again.
The external oblique muscles are located superficially on either side of your six pack muscles. They run along the sides of your abdomen. Twisting, turning, and bending engages the external obliques. These muscles work in tandem with all your other abdominal muscles to give your abdomen strength. Strong external obliques allow you to live a healthy, active lifestyle. The external obliques attach to the ribs.
The internal obliques have a similar function to the external obliques. They are located deeper in the abdomen. They attach to the ribs and linea alba. Both the internal and external oblique muscles rely on each other to flex and rotate your torso. Internal obliques are sometimes called “same side rotators”. Like the external obliques, they aid in supporting your abdominal wall.
Your deepest abdominal muscles are known as the transversus abdominis. It is located below all your other abdominal muscles and above your rib cage. When you perform core body exercises, these are the main muscles that you are working out.
The transversus abdominis is vital for good posture and lumbar support. It also helps hold the abdominal organs in place. If you have diastasis recti from pregnancy, this is the group of abdominal muscles you should focus on exercising. Doing so can reduce back pain from diastasis by improving spinal support.4
When you have diastasis recti from pregnancy, regaining core strength is essential. The transversus abdominis are the most important muscle group to work out in early recovery. This deep muscle group sets the foundation for all your other abdominals to work effectively. A fine-tuned body core keeps your tummy healthy and strong.
Structures below the core muscles
The transversalis fascia and peritoneum are both protective membranes that help keep your inner organs in tact. They aid in supporting your organs, giving your abdomen yet another layer of protection and strength.
The transverse fascia is located between the transversus muscle and the peritoneum. It lines the anterolateral abdominal wall. It is thick and dense, made up of tough fibers. In patients with hernia, a weak transversalis fascia is usually the culprit. When this fascia is damaged or weakened, the intestines can bulge through, causing pain when you bend, cough, or lift a heavy object. Hernias can be pretty painful.
Increased uterine pressure during pregnancy can also sometimes cause umbilical hernias. You may notice swelling or a bulge near the navel. Umbilical hernias are not dangerous per se and it won’t harm the baby, but it can cause discomfort. Surgery is the recommended treatment for hernias because they do not go away on their own.
Having a strong transversalis fascia can reduce your risk of hernias. But the transversalis fascia is a membrane, not a muscle. So there is not much you can do to regain strength to the membrane. However, it is always a good idea to eat healthy foods and maintain a proper body weight to help keep all parts of your body working properly.
The peritoneum is a serous membrane that lines the abdominal cavity and encases all your organs (except for the adrenal glands and kidneys). It is an important part of your abdominal wall anatomy. Not only does it give support to your abdominal organs, it also acts as a passageway for nerves, blood vessels, and lymphatics.
Summarizing abdominal wall anatomy
The seven layers of your abdominal wall work together to keep your tummy in good condition, both aesthetically and for proper strength and support. Body changes such as major weight gain or loss and pregnancy can make drastic changes to abdominal structures that may require exercise or surgery to repair.
- Farage, Miranda A., et al. “Characteristics of the Aging Skin.” Aging Clinical and Experimental Research, vol. 20, no. 3, 2008, pp. 195–200., doi:10.1007/bf03324769.
- Hunstad, Joseph P., and Remus Repta. Atlas of Abdominoplasty. Saunders/Elsevier, 2009.
- Pulei, A N, et al. “Distribution of Elastic Fibres in the Human Abdominal Linea Alba.” Anatomy Journal of Africa, vol. 4, no. 1, 2015, ajol.info/index.php/aja/article/view/118732.
- Sancho, M.f., et al. “Abdominal Exercises Affect Inter-Rectus Distance in Postpartum Women: a Two-Dimensional Ultrasound Study.” Physiotherapy, vol. 101, no. 3, 6 May 2015, pp. 286–291., doi:10.1016/j.physio.2015.04.004.
- Varani, James, et al. “Decreased Collagen Production in Chronologically Aged Skin.” The American Journal of Pathology, vol. 168, no. 6, 2006, pp. 1861–1868., doi:10.2353/ajpath.2006.051302.