When the thorax is fixed, they can pull up the pelvis and finally, they can bend the vertebral column sideways and assist in the trunks rotation. Posture
The transverse abdominis muscle is the deepest muscle, therefore, it cannot be touched from the outside. It can greatly affect the bodys posture. The internal obliques are also deep and also affect body posture. Both of them are involved in rotation and lateral flexion of the spine and are used to bend and support the spine from the front. The external obliques are more superficial and they are also involved in rotation and lateral flexion of the spine. Also they stabilize the spine when upright. The rectus abdominis muscle is not the most superficial abdominal muscle. The tendonous sheath extending from the external obliques cover the rectus abdominis. The rectus abdominis is the muscle that very fit people develop into the 6-pack ab look. Although it should really be a 10 pack as there are 5 vertical sections on each side. The 2 bottom sections are just above the pubic bone and usually not visible, hence, the 6 pack abs. The rectus abdominals function is to bend ones back forward (flexion). The main work of the abdominal muscles is to bend the spine forward when contracting concentrically. Society and culture
Social and cultural perceptions of the outward appearance of the abdomen has varying significance around the world.
The abdomen in vertebrates contains a number of organs belonging to, for instance, the digestive system, urinary system, and muscular system. Contents
The abdominal cavity contains most organs of the digestive system, including the stomach, the small intestine, and the colon with its attached appendix. Other digestive organs are known as the accessory digestive organs and include the liver, its attached gallbladder, and the pancreas, and these communicate with the rest of the system via various ducts. The spleen, and organs of the urinary system including the kidneys, and adrenal glands also lie within the abdomen, along with many blood vessels including the aorta and inferior vena cava. The urinary bladder, uterus, fallopian tubes, and ovaries may be seen as either abdominal organs or as pelvic organs. Finally, the abdomen contains an extensive membrane called the peritoneum. A fold of peritoneum may completely cover certain organs, whereas it may cover only one side of organs that usually lie closer to the abdominal wall. This is called the retroperitoneum, and the kidneys and ureters are known as retroperitoneal organs. Abdominal organs can be highly specialized in some animals. For example, the stomach of ruminants, (a suborder of mammals that includes cattle and sheep), is divided into four chambers – rumen, reticulum, omasum and abomasum. Muscles
There are three layers of muscles in the abdominal wall. They are, from the outside to the inside: external oblique, internal oblique, and transverse abdominal.