The Three Category System in SOT

What is the Three Category System?

The Three Category System is a foundational classification framework used within Sacro Occipital Technique (SOT) to help practitioners understand and address different patterns of dysfunction in the body. Developed by Dr Major Bertrand DeJarnette, this system provides a structured approach to identifying the primary area of concern and selecting appropriate treatment protocols.

Rather than treating symptoms in isolation, SOT practitioners use this classification system to understand the underlying mechanical and neurological patterns that may be contributing to a patient's presentation. The three categories — Category I, Category II, and Category III — each represent distinct patterns with their own characteristic findings and treatment approaches.

Category I: The Craniosacral Mechanism

Category I relates primarily to the craniosacral respiratory mechanism — the subtle rhythmic movement of cerebrospinal fluid (CSF) between the cranium and the sacrum. This category addresses dysfunction in the dural membrane system that surrounds and protects the brain and spinal cord.

What Practitioners Look For

SOT practitioners assess Category I patterns through specific indicator systems that may include:

• Occipital fiber patterns — Tension patterns at the base of the skull that may indicate dural tension
• Cranial suture restrictions — Limited movement between cranial bones
• Sacral base position — The orientation of the sacrum and its relationship to the pelvis
• Leg length checks — Specific positioning tests that may reveal functional imbalances

The Blocking Procedure

For Category I, practitioners typically use pelvic blocking — placing specially designed wedges under the pelvis in specific configurations. The patient lies face-down, and their body weight combined with gravity helps facilitate normal sacral movement and CSF dynamics. This gentle approach aims to encourage the body's natural self-correcting mechanisms.

Category II: Sacroiliac and Pelvic Stability

Category II focuses on sacroiliac joint dysfunction and pelvic weight-bearing patterns. This category addresses situations where the normal relationship between the sacrum and the ilium (the large pelvic bones) has been compromised, potentially affecting the entire kinetic chain from the feet to the spine.

Common Presentations

Patients who may fall into Category II often present with:

• Pelvic or hip pain, particularly with weight-bearing activities
• Low back pain that worsens with prolonged standing or walking
• Difficulty with transitional movements (sitting to standing)
• History of falls, accidents, or pregnancy-related pelvic changes

Category II Blocking

The blocking procedure for Category II differs from Category I. Wedges are placed to address the specific sacroiliac dysfunction identified during examination. The goal is to help restore normal pelvic mechanics and weight distribution through the lower body.

Category III: Localised Spinal Issues

Category III addresses more localised structural issues, particularly in the lumbar spine. This category is often considered when there is clear segmental dysfunction, disc-related concerns, or specific vertebral misalignment patterns that require direct attention.

When Category III May Apply

• Acute low back pain with clear mechanical triggers
• Radicular symptoms (pain, numbness, or tingling radiating into the legs)
• History of disc herniation or degenerative changes
• Post-surgical spinal considerations

Treatment Approach

Category III treatment may involve a combination of blocking and other SOT-specific techniques designed to address the localised dysfunction. The approach is typically more focused on the specific spinal segments involved while still maintaining awareness of the broader craniosacral system.

How Practitioners Determine Your Category

The category determination process involves a comprehensive assessment that may include:

• Detailed history taking — Understanding your symptoms, their onset, and any contributing factors
• Physical examination — Postural analysis, range of motion testing, and orthopaedic assessments
• Indicator system evaluation — Specific SOT assessment procedures including occipital fiber analysis
• Leg length and positioning tests — Functional assessments that help identify patterns

It's important to understand that categories are not rigid diagnoses but rather frameworks to guide treatment selection. Some patients may present with elements of multiple categories, and the primary category may change over the course of care.

Relationship Between Categories and Treatment Progression

One of the unique aspects of SOT is the understanding that categories can influence each other. For example, chronic Category II patterns may eventually contribute to Category I dysfunction, or unresolved Category I issues may predispose a patient to Category III presentations.

Practitioners typically prioritise treatment based on the most significant finding, with the understanding that addressing the primary category may have positive effects on secondary patterns. Treatment progression is monitored through ongoing reassessment of the indicator systems.

Evidence and Research

While the Three Category System has been used in SOT practice for decades, it's important to note that high-quality research specifically validating this classification system is limited. Most of the evidence is observational or based on clinical experience rather than randomised controlled trials.

That said, some studies have explored aspects of SOT's approach. A 2019 systematic review in the Journal of Chiropractic Medicine noted that while SOT shows promise for certain conditions, more rigorous research is needed to fully understand its mechanisms and effectiveness. The category system remains primarily a clinical tool rather than an evidence-based classification.

When to See Your GP Instead

While SOT may be appropriate for many musculoskeletal complaints, certain symptoms require medical evaluation. Seek immediate medical attention if you experience:

• Severe or progressive neurological symptoms — Weakness, numbness, or loss of bladder/bowel control
• Signs of infection — Fever with back pain, particularly if you have a history of IV drug use or recent infection
• Unexplained weight loss — Especially when accompanied by persistent pain
• History of cancer — New onset back pain in patients with a cancer history requires medical clearance
• Recent significant trauma — Falls, car accidents, or other injuries causing severe pain
• Night pain that doesn't improve with position changes — This may indicate more serious underlying pathology

Your chiropractor should refer you to a medical doctor if any red flags are identified during examination. Chiropractic care is complementary to, not a replacement for, appropriate medical care.