Understanding the anatomy of oblique muscles and how they work helps you perform your exercises more efficiently. In other words, you get better results faster if you know what you are doing.
Basic anatomy of the oblique muscles
The abdominal muscles work together to move the spine and compress the abdominal viscera. Oblique muscles are classified into two types: external oblique muscles and internal oblique muscles, each with its own origin and function. The oblique muscles are two of three muscle layers that surround the abdominal wall, the third layer being the transversus abdominis muscle.
External oblique muscle
It is the largest muscle on both sides of the trunk. The muscle fibers run from the lower ribs to the pelvis and are located beneath the thoracic (chest) and abdominal skin (hip bone). The lateral part of the abdominal wall is made up of muscle. The muscle contributes to a wide range of trunk movements and is primarily responsible for functions such as twisting the trunk’s sides, pulling the chest downwards, and rotating the spine. Muscle strain, injury, or trauma of any kind can be crippling.
Functions of the external oblique muscle
Depending on whether it contracts unilaterally (on one side) or bilaterally (on both sides), the external abdominal oblique muscle performs a variety of functions (both sides). It rotates the trunk to the opposite side when acting unilaterally and in synergy with the internal oblique muscle. When combined with back muscles, it contributes to sideways trunk bending. When you contract on both sides, you cause the trunk to flex forward (bend forward). This activity also increases abdominal wall tone and positive intra-abdominal pressure, which is involved in a variety of physiological processes such as forced exhalation, defecation (passing stools), micturition (urinating), and labor (childbirth).
Internal oblique muscle
It is a broad, thin muscular sheet that runs along the sides of the abdomen, perpendicular (at right angles) and deep to the external oblique muscle. It has multiple origin sites and is classified as anterior (front) fibers, posterior (hind) fibers, and lateral (sideways) fibers based on where they originate. This muscle works in opposition to the diaphragm, reducing the volume of the upper chest cavity during exhalation. This muscle’s contraction also rotates and bends the trunk sideways. The muscle is also referred to as the “same side rotator.”
Internal oblique muscle functions
Internal abdominal oblique muscle, along with other abdominal wall muscles, is important for maintaining normal abdominal wall tension. The contraction of these muscles serves as both a protective and a supportive function. This muscle’s bilateral (both sides) contraction raises intra-abdominal pressure and aids in functions such as forced expiration (exhalation), micturition (urination), and defecation (passing stools). The risk of abdominal hernias is increased when these muscles are weak.
Now that you know what obliques do, let’s look at four exercises to help you get started. Click on the images for animation.
Contralateral Supine Toe Touch
Russian Twist Elevated Feet
Twist From Side Plank
Side Leg Raise
