Retrospective Study of Cranial Strain Pattern Prevalence in a Healthy Population

Context: Research studies have associated cranial strain patterns with a variety of neurologic disorders. However, baseline data on the prevalence of such patterns in a healthy population is lacking. Objective: To determine the prevalence of cranial strain patterns in healthy subjects. Methods: A retrospective analysis of cranial strain findings from healthy subjects who participated in two previous research projects. Data were collected for the following cranial strain patterns: torsion (left or right), sidebending rotation (left or right), lateral (left or right), and vertical (superior or inferior). Results: Data from 142 healthy subjects-119 women and 23 men with a mean age of 24.5 years-were analyzed. Torsion and sidebending rotation were the most common cranial strain patterns observed, comprising 72% of all identified patterns. The most prevalent patterns when stratified by the side of dysfunction were right torsion (31%), left sidebending rotation (23%), and left lateral (19%). Left sidebending rotation with right torsion (17%); left lateral, left sidebending rotation, and right torsion (14%); and right sidebending rotation with right torsion (11%) were the most common combinations of cranial stain patterns. Conclusion: Although the present study identified common cranial strain patterns in a healthy population, future studies with broader patient populations and multiple observers are needed to confirm and further define these findings.