The frequency and presentation of upper thoracic spinous process deviations, their relationship to articular morphology, and the potential influence on static palpation techniques

Background: Static palpation of vertebral spinous process deviations from the midline are often utilized by manual therapists as a means to determine area for treatment of manipulable lesions. Previous research has discussed the diagnostic validity of this technique, but no correlation to vertebral morphology has been presented. Aim: To evaluate the frequency and presentation of vertebral spinous process deviations and their relationship with articular morphology, and the impact this may have in terms of static palpation techniques in the upper thoracic spine. Setting: This study was conducted on human T1-T6 vertebrae. Method: A skeletal sample consisting of 58 humans T1-T6 vertebrae were photographed and linear and angular measurements taken utilizing ImageJ software and non-metric visual observations. Results: Spinous process deviations in the entire sample group (n = 348) were found to occur in a frequency ranging from 19% (n = 11) at T1 to 41.4% (n = 24) at T3. However, when evaluated in terms of frequency within an individual's T1-T6, 83.3% (n = 25) of males and 67.86% (n = 19) of females demonstrated this feature, with an overall incidence of 77.59% (n = 45). Age of individuals did not show an increase in frequency, and no clear pattern could be identified regarding metric measurements and its presence. Conclusion: Spinous process deviations in the upper thoracic spine are most probably the result of random normal variations between individuals and are more frequent in males. Static palpation without pain criteria is not a reliable diagnostic technique to determine areas needing manual treatment, as these may be considered normal osseous anatomical variations.