Sherrie Hebert

Sherrie Hebert

When you think of your abs, do you see your six-pack, even though it may be a bit hidden like mine, or do you see an intricate network of muscles protecting your vital organs and providing the strength and support for your posture? I knew it would be the latter so this week we will chat about your abs’ anatomy and next week we will dive into exercises to strengthen those deep, supportive core muscles.

The abdominals consist of four muscles, each with a special purposed, yet working together as a whole: the internal and external obliques, transverse abdominis and rectus abdominis. The muscles create the abdominal cavity which surrounds the stomach, liver, gallbladder, spleen, small and large intestines, kidneys and the adrenal glands.

The rectus abdominis, well known as the “six pack,” flexes your spinal column between the ribs and pelvis. The rectus abdominis gets its six-pack shape from a long, fibrous sheath called the linea alba that divides the muscle down the middle from ribs five, six and seven to your pubic bone and three horizontal fibrous bands called the tendinous intersections located at the base of your sternum, your belly button and one between.

The external and internal obliques are at right angles to each other and allow you to twist and bend your torso to the side. Positioned as such, when they contract the opposite side rotates or bends. For example, to rotate the trunk to the left, the right external obliques contract and when the rotating the trunk to the right, the left external obliques will contract.

The fan-shaped external obliques are the top most and largest abdominal muscles that are positioned on both sides of the rectus abdominis. They originate from the lower eight ribs and fan diagonally down each side connecting to the iliac crest (the top of your hip bone), linea alba and pubic bone. The internal obliques lie below the external obliques originating at the lower three ribs to the linea alba and from the inguinal ligament (a ligament that runs from the iliac crest to the pubic bone) and the lower back. To visualize your obliques, the external obliques run diagonally downward as if you were putting your hands in your coat pockets. Placing your hands on the opposite side of your torso and spreading your fingers will show the upward angle of the internal obliques.

The transverse abdominis, the deepest abdominal muscle, helps to powerfully force air from the lungs and stabilize the low back and pelvis. Originating from the inguinal ligament and the iliac crest, the lower six ribs and the thoracolumbar fascia (a large, fat sheath of fascial tissue covering the much of the back between thoracic and lumbar spine), it wraps around like a corset inserting into the linea alba and pubic bone.

Having passed your ab anatomy this week and understanding where the muscles are and what they do, next week I will teach you with the abs-olute best exercises for a strong, stabilizing core and the best way — or place — to get your own six pack.

Sherrie Hebert is a certified personal trainer and Pilates mat and equipment Instructor. She teaches and trains at Performance Pilates & Personal Training and Gold’s Gym of Pocatello. Contact her at 208-478-2433 or for all your fitness needs. Be sure to visit her Facebook page, PerformancePilatesAndPT.