Key Points

• Researchers found that pain arising from the lumbar Z joints accounts for 10–15 percent of mechanical back pain in young adults and up to 40 percent of cases in older people.

• Leveling the head and tail is a biomechanical approach to restoring balance and function to the musculoskeletal system by addressing postural imbalances in the cervical and sacral regions.

According to the latest information on the prevalence of low-back pain in the US, the Centers for Disease Control and Prevention (CDC) reports that 60 percent of adults 18 years or older experienced low-back pain within the last three months.¹ Of this group, 20 percent report chronic pain lasting 12 weeks or longer. Low-back pain is the single leading cause of disability worldwide.²

The symptoms of low-back pain include localized pain and stiffness in the lower back, often on one side. Some people experience localized tenderness over affected vertebrae and pain that increases with specific movements, especially extension or rotation. Spasms are present in surrounding muscles, and sitting causes increased pain. In chronic cases, diffuse pain may spread to the buttocks, groin, or down the leg. 

Several structures in the lumbar spine might serve as pain generators, making it difficult to determine the etiology of low-back pain. However, researchers increasingly point to the zygapophyseal joints (Image 1), also called Z joints or facet joints, as primary pain generators in low-back conditions.³

In one study, researchers found that pain arising from the lumbar Z joints accounts for 10–15 percent of mechanical back pain in young adults and up to 40 percent of cases in older people.⁴ In a cadaveric study of 647 lumbar spines, researchers discovered evidence of degenerative changes in Z joints in 60 percent of adults by the time they reach age 30. Moreover, the degeneration continues and is pervasive by age 70.⁵

In this article, we’ll discuss Z joints and their role in low-back pain. We’ll identify a holistic approach to working with the spine and practice two myoskeletal alignment techniques (MAT) that help us normalize Z joint movement.

Z Joint Anatomy 

The zygapophyseal joints are a crucial component of the human vertebral column, contributing to its stability, flexibility, and load-bearing capabilities. Z joints are paired synovial joints formed from the superior articular processes of one vertebra and the inferior articular processes of the vertebra above. Z joints are the only synovial joints in the spine, with hyaline cartilage overlaying subchondral bone, a synovial membrane, and a joint capsule. Synovial fluid lubricates the joint, nourishes the articular cartilage, and facilitates smooth gliding of the articular surfaces. 

These joints function to stabilize the spine and limit axial rotation. Researchers estimate that Z joints carry about 25 percent of the dynamic axial load.⁶ Together with the intervertebral discs, Z joints help distribute the weight of the upper body evenly along the vertebral column, preventing excessive stress on any single vertebra. 

Degenerative Changes in Z Joints

Like other synovial joints, Z joints can undergo degenerative changes over time. The breakdown of the articular cartilage, development of bone spurs (osteophytes), and a reduction in the joint’s ability to absorb shock characterize osteoarthritis of the Z joints (Image 2). As osteophytes form, the bony outgrowths place pressure on adjacent structures such as spinal nerves, intervertebral discs, ligaments, the facet joint capsule, and nearby muscles. The synovium (the membrane that produces synovial fluid) often becomes inflamed, exacerbating pain and stiffness. Associated conditions—like intervertebral disc degeneration—narrow the disc space, altering mechanical load distribution and resulting in progressive stress on Z joint articulations and joint capsules.⁷

The cartilage and synovium of Z joints are sources of cytokines. Cytokines are potent mediators of inflammation and can perpetuate cycles of inflammation within the joint. Cytokines sensitize nociceptors, lowering the threshold for pain and making Z joints more sensitive to even minor stimuli.⁸ The stimulation of sensory nerve fibers leads to the release of substance P and calcitonin gene-related peptide (CGRP). These neuropeptides cause vasodilation, increased blood flow, and further inflammation. Persistent nociceptive signaling causes central sensitization in the spinal cord and brain, resulting in increased responsiveness of neurons in the central nervous system to threat signals, amplifying pain perception.⁹ 

The musculoskeletal system responds to this inflammatory cascade by sending muscles like the multifidus, rotatores, interspinales, intertransversarii, erector spinae, and quadratus lumborum into protective spasm. These muscles attempt to stabilize the vertebral column, causing additional pain, reduced movement, and inhibited muscle function. Additionally, inflammatory cytokines can affect motor control pathways in the nervous system, leading to altered muscle recruitment patterns and loss of coordination.¹⁰

Postural Causes of Osteoarthritis in Z Joints 

Injury, trauma, obesity, genetic predisposition, and age contribute to the development of Z joint osteoarthritis. Poor posture is a critical factor for much of the population experiencing low-back pain. 

Throughout adult life, the superior and inferior facets of the lumbar vertebrae reflect the different stresses placed upon them. As you might suspect, damage occurs in regions that experience the greatest mechanical forces.¹¹ Often, the cartilage in the central region of the facet joints is spared, with the majority of changes occurring where the articular processes contact one another during flexion and extension.¹²

Any postural habits that disrupt the spine’s natural curvature exacerbate this type of wear on Z joint cartilage. Examples include excessive lordosis caused by locked knees in standing postures or excessive kyphosis caused by slouching over a keyboard. Poor posture involves muscle imbalances that can alter the movement patterns of the spine, affecting the alignment and function of the Z joints.¹³ 

Similarly, poor posture in weight-bearing positions increases joint compression, accelerating cartilage degeneration. Degeneration is worsened by repetitive movement and work activities involving frequent heavy lifting, especially when combined with improper lifting techniques or prolonged sitting, such as desk work or driving.¹⁴ 

Myoskeletal Alignment Techniques for Z Joint Pain 

If you follow this column, you know that one of the central tenets of MAT is recognizing that the body operates as an interconnected unit. So, we won’t “chase pain” by focusing only on the low back. Instead, we’ll “level the head and tail” before applying targeted techniques to free the Z joints. 

Leveling the head and tail is a biomechanical approach to restoring balance and function to the musculoskeletal system by addressing postural imbalances in the cervical and sacral regions. The brain wants the head to sit on an even platform to allow maximum head-on-neck rotation. When the head is poorly aligned, the brain tries to compensate. As a result, some muscles overwork while others turn off, creating ongoing cycles of tension, pain, weak posture, and reduced mobility. 

Master Myoskeletal Therapists use movement to free the joints of the cervical vertebrae. Movement captures the brain’s attention by introducing novel stimuli that help reset faulty nervous system responses. As the body begins safely engaging with painful movement barriers, it releases protective guarding. Passive, active, and resisted movement, nerve flossing, and muscle spindle stimulation reprogram the nervous system and allow a return to balance. 

Just as the head needs to sit on a level platform, so does the spine. Motor dominance, leg-length discrepancies, prolonged sitting, and other factors that cause pelvic tilts and rotations create an uneven sacral base. 

Massage therapists are often quick to address these issues with deep work on low-back muscles, the rectus femoris, and iliopsoas. Master Myoskeletal Therapists typically choose movement first, as illustrated by Image 3 in a technique that frees the SI joint. Graded-exposure stretching helps us reduce muscle tension and balance the innominates. As we expose the nervous system to new movement possibilities, we reduce the threat of pain. Soon, the body feels safe to down-regulate nervous system activity and drop protective muscle guarding. We can use deep friction, if necessary, but we are just as likely to apply muscle spindle activation techniques to wake up inhibited muscles and nerve flossing to free trapped nerves. 

Having addressed the “head and tail,” we are ready to move into graded-exposure stretching maneuvers that help restore Z joint movement. 

Techniques that Free the Z Joints 

While there are many techniques to reduce pain and improve Z joint function, the two methods here provide great results. 

Iliosacral Alignment Technique (Image 4)

This is an indirect approach that helps level the sacral base, creating the conditions for proper Z joint alignment. With the client prone, your right hand lifts the client’s right ilium while your left palm braces the left posterior superior iliac spine. Gently pull with your right hand while resisting with your left. Ask the client to gently push their right ilium toward the table to a count of five and relax. You rotate the client’s pelvis to the next restrictive barrier to help restore Z joint alignment. Repeat this maneuver 3–5 times and then repeat on the other side. 

Z Joint Opening (Image 5)

This technique decompresses the Z joints. Face the client and place the client’s knees in a slightly flexed position. Lift the client’s left flexed knee and place it against your belly. Your left hip supports the client’s leg so when you step to your left foot, you initiate greater hip flexion. Contact the left L5 transverse process (or the lamina groove) with the fingers of your right hand. Now, step onto your left foot, flexing the client’s hip while you use the fingers of your right hand to drag the sacrum away from L5. Make sure your fingers are hooking deep in the groove and the client’s knee is flexed tight as you step onto your left foot. Move your fingers to L4 and repeat this process. Repeat the entire process with the client lying on the other side.

Stretch and Move to Relieve Pain

Low-back pain is a prevalent and debilitating condition affecting a significant portion of the adult population. The Z joints are increasingly recognized as primary pain generators in low-back conditions. 

Poor posture is a significant contributing factor to Z joint degeneration. Disruptions in the natural spinal curvature, caused by various postural habits, can accelerate wear on the cartilage and lead to joint compression. MAT offers a holistic approach to addressing low-back pain by “leveling the head and tail.” By restoring balance in the cervical and sacral regions, MAT aims to reset faulty nervous system responses and reduce tension, pain, and weakness.

Graded-exposure stretching and movement are key components of MAT to improve Z joint function. Techniques like passive sidebending and iliosacral alignment can effectively decompress and align the Z joints, providing relief and restoring function. 

Notes

1. Centers for Disease Control and Prevention, “QuickStats: Percentage of Adults Aged 18 Years or Older Who Had Lower Back Pain in the Past 3 Months. National Health Interview Survey, United States, 2018,” January 2020, http:// dx.doi.org/10.15585/mmwr.mm685152a5. 

2. World Health Organization, “Low Back Pain,” June 2023, www.who.int/news-room/fact-sheets/detail/low-back-pain. 

3. Laxmaiah Manchikanti et al., “Prevalence of Facet Joint Pain in Chronic Low Back Pain in Postsurgical Patients by Controlled Comparative Local Anesthetic Blocks,” Archives of Physical Medicine and Rehabilitation 88, no. 4 (2007): 449–55, https://pubmed.ncbi.nlm.nih.gov/17398245; Nalini Sehgal et al., “Diagnostic Utility of Facet (Zygapophysial) Joint Injections in Chronic Spinal Pain: A Systematic Review of Evidence,” Pain Physician 8, no. 2 (2005): 211–24, https://pubmed.ncbi.nlm.nih.gov/16850075.

4. Mark A. Jackson and Karen H. Simpson, “Chronic Back Pain,” Continuing Education in Anaesthesia, Critical Care & Pain 6, no. 4 (August 2006): 152–5, https://doi.org/10.1093/bjaceaccp/mkl029. 

5. K. Saravanakumar and A. Harvey, “Lumbar Zygapophyseal (Facet) Joint Pain,” Reviews in Pain 2, no. 1 (2008): 8–13, https://pubmed.ncbi.nlm.nih.gov/26525677. 

6. Tomoyuki Takigawa et al., “Spinal Kinematics and Facet Load Transmission After Total Disc Replacement,” Spine 35, no. 22 (October 2010): E1160–6, https://pubmed.ncbi.nlm.nih.gov/20881657. 

7. Jesse S. Little and Partap S. Khalsa, “Human Lumbar Spine Creep During Cyclic and Static Flexion: Creep Rate, Biomechanics, and Facet Joint Capsule Strain,” Annals of Biomedical Engineering 33, no. 3 (March 2005), 391–401, https://pubmed.ncbi.nlm.nih.gov/15868730. 

8. David S. Binder and Devi E. Nampiaparampil, “The Provocative Lumbar Facet Joint,” Current Reviews in Musculoskeletal Medicine 2, no. 1 (2009): 15–24, www.ncbi.nlm.nih.gov/pmc/articles/PMC2684949.

9. Alfred C. Gellhorn, Jeffrey N. Katz, and Pradeep Suri, “Osteoarthritis of the Spine: The Facet Joints,” Nature Reviews Rheumatology 9, no. 4 (April 2013): 216-24, www.ncbi.nlm.nih.gov/pmc/articles/PMC4012322. 

10. Ulrich Hoheisel, Thomas Unger, and Siegfried Mense, “Excitatory and Modulatory Effects of Inflammatory Cytokines and Neurotrophins on Mechanosensitive Group IV Muscle Afferents in the Rat,” Pain 114, nos. 1–2 (March 2005), 168–76, https://pubmed.ncbi.nlm.nih.gov/15733642.

11. Thomas Tischer et al., “Detailed Pathological Changes of Human Lumbar Facet Joints L1–L5 in Elderly Individuals,” European Spine Journal 15, no. 3 (March 2006): 308–15, https://pubmed.ncbi.nlm.nih.gov/16021481. 

12. Bronek M. Boszczyk et al., “Immunohistochemical Analysis of the Extracellular Matrix in the Posterior Capsule of the Zygapophysial Joints in Patients with Degenerative L4–5 Motion Segment Instability,” Journal of Neurosurgery 99, no. 1 supplemental (July 2003): 27–33, https://pubmed.ncbi.nlm.nih.gov/12859055. 

13. Frances Wilder, Lissa Fahlman, and Robert Donnelly, “Radiographic Cervical Spine Osteoarthritis Progression Rates: A Longitudinal Assessment,” Rheumatology International 31, no. 1 (January 2011): 45-8, https://pubmed.ncbi.nlm.nih.gov/19865817; Steven P. Cohen and Srinivasa N. Raja, “Pathogenesis, Diagnosis, and Treatment of Lumbar Zygapophysial (Facet) Joint Pain,” Anesthesiology 106, no. 3 (March 2007): 591–614, https://pubmed.ncbi.nlm.nih.gov/17325518. 

14. Gellhorn, “Osteoarthritis of the Spine: The Facet Joints.”