The external obliques on either side not only help rotate the trunk, but they perform a few other vital functions. These muscles help pull the chest, as a whole, downwards, which compresses the abdominal cavity. Although relatively minor in scope, the external oblique muscle also supports the rotation of the spine. Since the muscle contributes to a variety of trunk movements, strain or injury to the muscle can be debilitating. This may include movements that do not directly use the muscle. For example, ambulatory motions such as walking or running, which cause slight movements in the torso.

External Oblique/Abdominal Oblique/Oblique Muscle

The external oblique is situated on the lateral and anterior parts of the abdomen. It is broad, thin, and irregularly quadrilateral, its muscular portion occupying the side, its aponeurosis the anterior wall of the abdomen. In most humans (especially females), the oblique is not visible, due to subcutaneous fat deposits and the small size of the muscle. It arises from eight fleshy digitations, each from the external surfaces and inferior borders of the fifth to twelfth ribs (lower eight ribs). These digitations are arranged in an oblique line which runs inferiorly and anteriorly, with the upper digitations being attached close to the cartilages of the corresponding ribs, the lowest to the apex of the cartilage of the last rib, the intermediate ones to the ribs at some distance from their cartilages.

external oblique

The five superior serrations increase in size from above downward, and are received between corresponding processes of the serratus anterior muscle; the three lower ones diminish in size from above downward and receive between them corresponding processes from the latissimus dorsi. From these attachments, the fleshy fibers proceed in various directions. Its posterior fibers from the ribs to the iliac crest form a free posterior border.

Those from the lowest ribs pass nearly vertically downward, and are inserted into the anterior half of the outer lip of the iliac crest; the middle and upper fibers, directed downward (inferiorly) and forward (anteriorly), become aponeurotic at approximately the midclavicular line and forms the anterior layer of the rectus sheath. This aponeurosis formed from fibers from either side of the external oblique decussates at the linea alba.

The aponeurosis of the external oblique muscle forms the inguinal ligament. The muscle also contributes to the inguinal canal. Just deep to the external oblique is the internal oblique muscle. These muscles are in the deepest layer of the abdominal wall.

External Oblique Ridge

• Continuation of the anterior border of the mandibular ramus.
• Arises lateral to alveolar process from 3rd molar to 1st molar area.
  

  External Oblique Ridge

• Thick in posterior areas, thinner anteriorly.
• Appears as linear radiopaque structure running obliquely downward and forward from the 3rd molar area.
• Internal oblique ridge: attachment of mylohyoid muscle, which supports the floor of the oral cavity it is LOWER (like a floor).
  

  External Oblique Ridge

• External oblique ridge: arises on the ascending ramus, so it is HIGHER (ascending).

External Oblique Function/Action

The external oblique functions to pull the chest downwards and compress the abdominal cavity, which increases the intra-abdominal pressure as in a valsalva maneuver. It also performs ipsilateral (same side) side-bending and contralateral (opposite side) rotation. So the right external oblique would side bend to the right and rotate to the left. The internal oblique muscle functions similarly except it rotates ipsilaterally.

External Oblique Exercises

If you’re looking to build a stronger core, you’ll have to focus on more than just your six-pack muscles.

Your obliques, which run along the sides of your core, are majorly important. The external abdominal oblique muscles are actually the largest of all your ab muscles so if you ignore them to focus on crunching away your rectus abdominus, your core routine will be far from efficient and effective.

The oblique muscles are tasked with a variety of functions. They help you bend your torso to the side, help rotate your torso to the left and right, and perhaps most important, actually act to resist your torso from rotating, which helps to stabilize and protect your spine. If you’re moving, you need these muscles. If you’re aiming for high-level performance, you need them to be strong.

external oblique muscle

The following 25 exercises train your obliques in all the ways they function, by using uneven loads, instability, or rotation. The result: You’ll challenge your obliques from every angle. Tack on these moves in your workout as is appropriate, or pair three to five of them together for a killer oblique circuit.

And for a complete fitness program that will not only build your abs muscles but also melt the flab that covers them, try Anarchy Abs or Anarchy 10 from Men’s Health. You’ll get five 30-minute calorie-torching workouts that employ a unique blend of metabolic training, traditional strength training, and gymnastics fundamentals to strip away fat from head to toe.

• Bird Dog Crunches.
• Single-Leg Side Plank with Leg Raise.
• Spiderman Crunch.
• Side Plank Swipers.
• Single-Leg Toe Touches.