08/18/2025
L4–S1: The Most Stressed Region of the Spine!!!
The L4–S1 segment is the most mechanically vulnerable area of the lumbar spine. These two discs absorb enormous compressive forces as the lumbar spine transitions into the pelvis. During standing, walking, bending, and lifting, L4–L5 and L5–S1 experience the highest loads of any spinal level. The lumbosacral angle also creates shear forces, further stressing these discs (Adams & Dolan, 2005).
Because of this constant stress, L4–S1 is the most frequent site of disc degeneration and herniation. Clinical research confirms that most symptomatic lumbar disc herniations occur at these two levels (Fardon & Milette, 2001). Disc compression here often irritates the L5 and S1 nerve roots, producing pain, weakness, or numbness that can radiate down the leg, commonly known as sciatica (Bogduk, 2012).
Traction and decompression are effective ways to temporarily reduce intradiscal pressure, widen the intervertebral foramen, and relieve mechanical stress on nerve roots. MRI studies demonstrate that spinal traction can increase disc height and reduce compression at L4–S1 (Clarke et al., 2007). While traction alone is not a cure, it plays a key role in multimodal rehabilitation, restoring mobility and reducing pain.
Traditional Thai massage techniques provide a manual, bodyweight-driven form of decompression that parallels clinical traction principles.
• Leg pulls and hip traction stretches create gentle axial distraction through the pelvis, unloading the L4–S1 discs.
• Assisted spinal twists mobilize the facet joints and reduce local guarding.
• Myofascial and acupressure techniques around the lumbar paraspinals, hip flexors, and gluteals release muscular tension that otherwise increases compression.
By integrating these methods with careful assessment, Thai medical massage offers therapists a safe, non-invasive way to restore space, reduce nerve irritation, and support recovery in the L4–S1 region.
References
• Adams, M. A., & Dolan, P. (2005). Spinal biomechanics. Journal of Biomechanics.
• Bogduk, N. (2012). Clinical Anatomy of the Lumbar Spine and Sacrum. Churchill Livingstone.
• Fardon, D. F., & Milette, P. C. (2001). Nomenclature and classification of lumbar disc pathology. Spine Journal.
• Clarke, J. A., et al. (2007). Traction for low-back pain with or without sciatica. Cochrane Database of Systematic Reviews.
