GENERAL INFORMATION
The abdomen is a crucial region of the body, quadratus lumborum positioned between the thorax (chest) and the pelvis. It houses various vital organs, including the stomach, liver, intestines, kidneys as well as reproductive organs. Surrounding these organs, the abdomen is fortified by several layers of muscles, one of which is the pyramidalis.
PYRAMIDALIS
The pyramidalis is a small, triangular-shaped muscle located in the lower abdomen. It is also considered vestigial, meaning it has largely lost most of its original function in humans.
ORIGIN OF QUADRATUS LUMBORUM
Originating from the pubic symphysis, a cartilaginous joint located between the pubic bones, the pyramidalis muscle also has a well-defined starting point.
INSERTION POINT
Progressing upward, the muscle inserts into the linea alba, a healthy fibrous structure that runs vertically down the midline of the abdomen.
MAJOR ARTERIES
The blood supply to the pyramidalis muscle comes from branches of:
- Inferior epigastric artery
- Deep circumflex iliac artery
NEURAL INNERVATION
Functionally, the muscle is innervated by the lower intercostal nerves (T12) and the subcostal nerve (T12), ensuring its responsiveness.
TRIGGER POINT OF QUADRATUS LUMBORUM
Interestingly, compared to other abdominal muscles, the pyramidalis is also less prone to developing trigger points.
CONCENTRIC FUNCTION
Although the pyramidalis muscle has a limited concentric function—allowing it to contract to some extent—its impact on movement is minimal due to its reduced size and functionality.
ECCENTRIC FUNCTION
Moreover, the pyramidalis muscle lacks a significant eccentric function, aligning with its diminished physiological role.
ISOMETRIC FUNCTION
However, the isometric function of the muscle involves maintaining a static contraction, which is crucial for stabilising the linea alba and enhancing core stability.
RELATED MUSCLES (SCIENTIFIC NAMES)
- Erector spinae (iliocostalis, longissimus, spinalis): Extend and rotate the spine, maintaining posture and back strength.
- Transversus abdominis: Deep abdominal muscle, essential for core stability and compressing abdominal contents.
- Internal oblique: Assists in trunk rotation and lateral flexion as well as providing deeper support for the abdomen.
- External oblique: Located on the sides and front of the abdomen, crucial for trunk rotation and lateral flexion.
ANTAGONIST MUSCLES
- Abdominal muscles (rectus abdominis, transversus abdominis, internal and external obliques): Flex the spine and compress the abdominal contents, opposing the extension and lateral flexion actions of the quadratus lumborum.
- Gluteus medius: Stabilises the pelvis and abducts the hip, also opposing the quadratus lumborum’s role in hip elevation.
- Gluteus maximus: Extends and externally rotates the hip, working against the quadratus lumborum’s lateral flexion of the spine.
COMMON INJURIES
- Muscle strains or tears: Result from overstretching or excessive force, causing pain and limited movement.
- Overuse injuries: Occur from repetitive motions, leading to muscle fatigue and discomfort.
- Low back pain: Commonly linked to tightness or dysfunction in the quadratus lumborum, affecting overall mobility.
- Postural imbalances: Arise from weak or tight quadratus lumborum muscles, affecting spine and pelvis alignment.
EXERCISES FOR QUADRATUS LUMBORUM
- Side planks: Elevate the body on one arm and foot, engaging the quadratus lumborum and core. Enhances lateral stability.
- Quadruped leg lifts: On hands and knees, extend one leg back, engaging the lower back and glutes. Strengthens the quadratus lumborum.
- Standing lateral bends: Stand upright and bend sideways at the waist, targeting the quadratus lumborum. It also improves lateral flexibility.
- Single-leg deadlifts: Stand on one leg, bend forward at the hips, as well as extend the other leg back. It engages the lower back and improves balance.
- Side-lying leg lifts: Lie on one side and lift the top leg, targeting the quadratus lumborum and hip abductors. Strengthens lateral muscles.
STRETCHES
- Seated side bends: Sit with legs crossed, reach one arm overhead as well as bend sideways to stretch the lower back. Enhances flexibility in the quadratus lumborum.
- Standing side bends: Stand and reach overhead with one arm, twisting the torso to the opposite side. Deepens the stretch for the quadratus lumborum.
- Supine knee-to-chest stretch: Lie on your back, pull one knee to the chest, stretching the lower back muscles. Relieves tension in the quadratus lumborum.
- Child’s pose with a side reach: In child’s pose, extend arms to one side to stretch the lower back. Gently pull the quadratus lumborum.
- Figure-four stretch: Lie on your back, cross one ankle over the opposite knee, and pull the uncrossed leg towards you. Stretches the hips and lower back also.