GENERAL INFORMATION
The abdomen is a region of the body located between the thorax (chest) and the pelvis. It contains various organs, including the stomach, liver, intestines, kidneys, and reproductive organs. Furthermore, the abdomen is surrounded by several layers of muscles, including the external oblique muscles.
EXTERNAL OBLIQUE MUSCLES
The external oblique muscles are a pair of broad, superficial muscles located on the sides and front of the abdomen. They contribute significantly to core stability, trunk rotation, and lateral flexion of the spine, so they play a vital role in various trunk movements and stability.
ORIGIN
External oblique muscles originate from the outer surfaces of the lower eight ribs. Consequently, their origin points provide a strong foundation for their function in trunk movement and stability.
INSERTION POINT
The External oblique muscles are inserted into the following structures:
- Linea alba: A fibrous structure that runs vertically down the midline of the abdomen.
- Anterior iliac crest: The upper edge of the hip bone.
- Pubic tubercle: A bony prominence on the front side of the pubic bone.
Thus, these insertion points are crucial for connecting the muscles to the abdominal and pelvic regions.
MAJOR ARTERIES
The external oblique muscles receive their blood supply from branches of the following arteries:
- Superior and inferior epigastric arteries
- Lumbar arteries
- Deep circumflex iliac artery
Consequently, these arteries ensure that the muscles receive adequate blood flow to perform their functions effectively.
NEURAL INNERVATION
The external oblique muscles are innervated by the lower intercostal nerves (T7-T12) and the first lumbar nerve (L1). Therefore, proper nerve function is essential for the activation and control of these muscles.
TRIGGER POINT
Trigger points in the external oblique muscles can cause localised pain in the abdominal region, which may also affect the lower back, hips, or groin. Addressing these trigger points through massage or other therapies can alleviate discomfort and improve muscle function.
CONCENTRIC FUNCTION
The external oblique muscles’ concentric function involves contracting the muscle fibres, resulting in trunk rotation to the opposite side and lateral flexion of the spine. Thus, they are essential for dynamic trunk movements.
ECCENTRIC FUNCTION
The eccentric function of the external oblique muscles refers to the controlled lengthening of the muscle fibres. It assists in the controlled lowering of the trunk during trunk rotation and lateral flexion movements, and it plays a critical role in maintaining stability during these movements.
ISOMETRIC FUNCTION
The isometric function of external oblique muscles involves maintaining a static contraction without any change in muscle length. This helps stabilise the trunk and maintain core stability during various movements, making them essential support during physical activities.
RELATED MUSCLES (SCIENTIFIC NAMES)
- Internal oblique: Located beneath the external oblique muscles, it assists in trunk rotation and lateral flexion, providing deeper support for the abdomen.
- Rectus abdominis: Runs vertically on the front of the abdomen, crucial for flexing the spine and forming the “six-pack” look.
- Transversus abdominis: The deepest abdominal muscle, essential for core stability and compressing the abdominal contents.
- Quadratus lumborum: Located in the lower back, it is important for lateral flexion and maintaining an upright posture.
ANTAGONIST MUSCLES
- Erector spinae muscles (iliocostalis, longissimus, spinalis): Extend and rotate the spine, opposing the flexion and rotation actions of the obliques, also which are vital for maintaining back strength.
- Rectus abdominis: Flexes the spine, opposing the extension function of the erector spinae, key for abdominal strength and stability.
COMMON INJURIES
- Muscle strains or tears: Caused by overstretching or overuse, leading to pain and limited movement, often from sudden or intense activities.
- Overuse injuries: Result from repetitive motions, causing muscle fatigue and discomfort, which is common in athletes and individuals with high activity levels.
- Abdominal hernias: Occur when an organ pushes through a weak spot in the abdominal muscles, often due to heavy lifting or strain.
- Postural imbalances: Arise from weak or tight oblique muscles, affecting overall posture and alignment, potentially leading to chronic pain and discomfort.
EXERCISES
- Russian twists: Sit on the floor, lean back slightly, and rotate the torso from side to side, engaging the obliques. This exercise improves rotational strength and core stability.
- Side plank variations: Elevate the body on one arm and foot, strengthening the obliques and core. Variations can include leg lifts or reaching movements to increase difficulty.
- Bicycle crunches: Lie on your back and alternate elbow-to-knee touches, targeting the obliques and rectus abdominis. This dynamic movement enhances overall core strength.
- Woodchoppers: Stand with feet shoulder-width apart, hold a weight, and mimic chopping wood, rotating from high to low. This motion effectively works the obliques and shoulders.
- Standing side bends: Stand upright and bend sideways at the waist, stretching and strengthening the obliques. Adding weights can increase resistance and effectiveness.
STRETCHES
- Standing side bends: Stand and reach overhead with one arm, twisting the torso to the opposite side to stretch the obliques. This stretch can be deepened by holding a lightweight.
- Seated side bends: Sit with legs crossed, reach one arm overhead, and bend sideways to stretch the obliques. This position provides a stable base for a deeper stretch.
- Supine spinal twists: Lie on your back, cross one leg over the other, and twist the torso to stretch the obliques and spine. Holding the stretch for longer periods can increase flexibility.
- Sphinx pose: Lie on your stomach, lift your upper body with your forearms, stretching the abdominal muscles. This gentle backbend can help open up the front body.
- Seated forward folds with a side reach: Sit with legs extended, reach one arm overhead, and bend towards the opposite leg. This stretch targets the sides of the body and improves flexibility.