
12/06/2025
Role of Quadratus Lumborum (QL) Length in Relation to Pelvic Shift in Intervertebral Disc Prolapse (IVDP):
In patients with intervertebral disc prolapse (IVDP), particularly lumbar disc herniations, pelvic shift is a common compensatory posture to alleviate nerve root compression and pain. This shift, often observed as a lateral deviation of the trunk or pelvis, can significantly influence the length-tension relationship of the quadratus lumborum (QL) muscle.
Key Points:
• The quadratus lumborum is a deep lumbar muscle that spans from the iliac crest to the 12th rib and lumbar vertebrae, playing a critical role in lateral flexion and pelvic stabilization.
• In pelvic shift toward the non-painful side (commonly seen in disc herniations impinging the nerve root), the QL on the convex side (shifted side) tends to lengthen, while the QL on the concave side becomes relatively shortened and hypertonic.
• This asymmetry in QL length can:
• Contribute to muscle imbalance and postural distortion.
• Exacerbate mechanical loading on the lumbar spine.
• Alter pelvic alignment, influencing lumbar lordosis and spinal stability.
Clinical Implication:
• Addressing QL dysfunction through manual therapy, targeted stretching, and neuromuscular re-education is vital in correcting pelvic shift and restoring spinal mechanics.
• A balanced QL function may reduce compensatory strain, assist in centralizing the disc, and support recovery from IVDP-related postural adaptations.
This muscle’s condition should be carefully evaluated during the rehabilitation and postural correction phase of IVDP management.