A/C Joint Separation: Gonstead Extremity Precision for Adults and Pediatrics
The acromioclavicular (A/C) joint may be one of the smallest articulations in the body, but it’s biomechanically among the most important. It connects the clavicle to the acromion of the scapula, maintaining synchronized motion between the upper extremity and the axial skeleton.
When this joint loses integrity—whether from trauma, repetitive stress, or ligamentous laxity—it disrupts the entire shoulder kinetic chain. In Gonstead extremity care, we see the A/C joint not as an isolated structure, but as part of a precise mechanical and neurological system extending from the cervical spine through the fingertips.
Understanding A/C Joint Separation
An A/C joint separation occurs when the acromioclavicular and/or coracoclavicular (C/C) ligaments are stretched or torn. Severity is graded from Type I through Type VI, depending on how much displacement and tissue disruption occur.
Mild (Type I–II): Ligament strain or partial tearing, joint remains congruent on imaging.
Moderate (Type III): Complete A/C and partial or full C/C rupture; visible elevation of the distal clavicle.
Severe (Type IV–VI): Significant displacement with posterior or inferior clavicular translation and soft tissue involvement.
Mechanisms often include a direct blow to the shoulder, a fall onto the lateral arm, or repetitive overhead loading—common in sports like baseball, volleyball, or cycling.
Gonstead Extremity Approach: Precision Above Protocol
The Gonstead system is rooted in measurable biomechanics. In extremity care, precision replaces generalization. Each joint is assessed radiographically and palpated with structural intent.
Key Adult X-Ray Measurements
A/C Joint Space:
Normal: 1–3 mm
Widening beyond 3 mm indicates A/C ligament injury.
Coracoclavicular (C/C) Distance:
Normal: 11–13 mm
A difference > 5 mm between sides, or > 25% increase, suggests partial or complete rupture.
Clavicular Alignment:
Evaluate for superior, posterior, or inferior displacement relative to the acromion and coracoid.
These measurements, combined with clinical findings, define both the grade of separation and the line of correction for adjustment.
Pediatric A/C Joint Measurements and Considerations
Children’s A/C joints cannot be measured using adult parameters because the distal clavicle and acromion are still cartilaginous and the physis (growth plate) remains open until the mid-teens. True ligamentous separations are uncommon; most pediatric “separations” are epiphyseal injuries—a subtle displacement at the growth plate.
Pediatric Measurement Guidelines
A/C Joint Space:
Appears wider (2–5 mm) than adults due to incomplete ossification.
Mild asymmetry between sides is common and typically physiologic.
Coracoclavicular (C/C) Distance:
Normal pediatric range: 8–12 mm (variable by age).
A side-to-side difference > 3 mm or an increase > 20% may indicate partial disruption or physeal separation.
Comparison Imaging:
Always obtain bilateral radiographs to account for developmental variance.
Evaluate for smooth contouring of the distal clavicle; irregularity may reflect physeal displacement rather than true ligament rupture.
Interpretation Tip (Gonstead View):
Evaluate clavicular angle in relation to the T1–T3 thoracic segments and scapular plane symmetry, not just coracoclavicular distance.
Pediatric corrections must respect open growth centers; use low-amplitude, controlled adjustments with precise line of drive.
By combining radiographic evaluation with functional analysis, Gonstead chiropractors can distinguish between a true separation and a pseudoseparation caused by developmental anatomy—ensuring safe and effective correction.
Restoring Alignment, Function, and Neurological Balance
When the A/C joint misaligns, the entire shoulder girdle compensates. Scapular elevation, altered glenohumeral tracking, and rib fixation often accompany the injury. The Gonstead extremity adjustment re-establishes normal motion through specific, directional correction—targeted along the exact vector of subluxation rather than a generalized mobilization.
This precision helps:
Restore normal shoulder biomechanics
Decrease nociceptive input and inflammation
Rebalance muscle tone across the deltoid, trapezius, and rotator cuff
Prevent compensatory patterns in the cervical and thoracic regions
For athletes and active adults, this means faster recovery, greater stability, and improved long-term performance.
Why Gonstead Extremity Training Matters
Chiropractors worldwide are rediscovering the value of extremity mastery within the Gonstead framework. The A/C joint is a prime example of why: it demands precision in both diagnosis and correction. Small misinterpretations lead to prolonged dysfunction; accurate analysis produces predictable results.
Dr. Bobby Fano’s national training programs teach chiropractors how to:
Read and interpret extremity radiographs with accuracy
Identify exact misalignment patterns
Adjust with precision, not force
Integrate extremity correction into full-body performance care
Conclusion
A/C joint injuries—whether in a professional athlete or a pediatric patient—require more than rest or rehabilitation. They demand structural clarity. The Gonstead extremity system provides that clarity by combining objective imaging, biomechanical logic, and artful precision in correction.
When alignment is restored, function follows — and so does performance.
