The osteopathic philosophy applies to manipulative treatment as well as viewing an individual as a whole entity. The neuromusculoskeletal system is important to sustaining a healthy life. The musculoskeletal system is intimately connected with all other systems of the body through both the voluntary and involuntary nervous systems. Osteopathic physicians are trained to evaluate the neuromusculoskeletal system and work to achieve normal body mechanics through the use of manual manipulative medicine.

Osteopathic physicians use palpatory examination to identify somatic dysfunctions. The accepted definition in the Glossary of Osteopathic Terminology is: "Somatic dysfunction is an impaired or altered function of related components of the somatic (body framework) system: Skeletal, arthrodial, and myo-fascial structures, and related vascular, lymphatic and neural elements". Physicians assess for texture changes, asymmetry, restriction of motion, and tenderness. After performing OMT, such as HVLA, a dysfunction is reassessed by palpatory assessment once again. While there are studies which show the effectiveness of OMT, a challenge remains to objectively assess a somatic dysfunction.

According to the Glossary of Osteopathic Terminology, HVLA technique is defined as "An osteopathic technique employing a rapid, therapeutic force of brief duration that travels a short distance within the anatomic range of motion of a joint, and that engages the restrictive barrier in one or more planes of motion to elicit release of restriction. It is also known as a thrust technique". The goal of the treatment is the restoration of physiological motion to the dysfunctional joint. In the past, osteopathic manipulation was synonymous with the thrust technique. This may have been because this technique can be taught by accurately describing the nature of the restriction and providing techniques for treating the dysfunction.

Proper diagnosis of a joint dysfunction is important for spinal manipulation. However, little assessment has been made of the clinician's ability to reliably identify a joint with biomechanical dysfunctions. Few studies attempts to address the challenge of evidence-based clinical practice. In a study by Degenhardt et al., investigators looked into the inter-observer reliability of the osteopathic palpatory tests. While the study showed that consensus training did show some improvement in the inter-observer reliability, many previously published studies failed to show a level of reproducibility that supports the use of palpation in evidence-based clinical practice. Najm et al. systematic review paper reasoned that one of the challenges behind evaluating the validity of palpatory assessment is due to the lack of a reference standard measuring means. The reference standard can be used to measure the findings made by palpation.

In a study conducted by Shaw et al. they were able to use an ultrasound machine to assess the content validity of palpatory examination as well as to provide objective evidence of the effect of HVLA on somatic dysfunction in the lumbar spine. We aim to adapt their protocol for the cervical spine. The study conducted by Shaw et al. did not have a control group. In our study, we aim to have a control group which will not be getting treatment in the cervical spine. The control group will be subjected to the cranial vault hold which is generally used to assess the primary respiratory mechanism in the cranium and degree of participation of each bone in the general motion of the cranium. In the experimental group, participants will be receiving cervical HVLA to the key somatic dysfunction segment. Based on Shaw et al. study, we hypothesize that an ultrasound is a reliable instrument to objectively evaluate somatic dysfunction of the cervical spine. Furthermore, we hypothesize that after performing cervical HVLA, the left and right articular pillars of the key somatic dysfunction vertebrae should be symmetrical compared to baseline.

Previous studies show certain effects observed after an HVLA manipulation. In a systematic review paper by Hegedus et al., it was found that after a single spinal joint mobilization, there were temporary neurophysiological effects for approximately 5 minutes or less. Studies that have revealed the neurophysiological effects of spinal manual therapy have caused a paradigm shift away from a strict biomechanical model. This is important because the neurophysiological effects include pain-related measures, changes in skin conductance, changes in skin temperature and improvements in range of motion with neural tensioning. In a study performed by Martinez-Segura et al., it was found that a single cervical HVLA manipulation was more effective in reducing neck pain at rest and increasing active cervical range of motion than a control mobilization procedure in subjects suffering from mechanical neck pain.

This research design holds significant importance. It can potentially prove intra- and inter-examiner reliability of palpatory assessment. In addition, ultrasonography can be used as a reference standard for evaluating somatic dysfunctions. Furthermore, this study will enable investigators to quantify the palpatory assessment and the extent to which HVLA has an effect on a key somatic dysfunction in the cervical spine. Using an ultrasound machine for the study holds many advantages. It is relatively safe and noninvasive. It enables investigators to visualize the cervical anatomy without any radiation and minimal harm to the participants. Using a cervical goniometric device, investigators will observe how the osteopathic techniques that are utilized in this study will affect active range of motion. The total time of participation is 60 minutes, and the change in range of motion from baseline to 1 hour following the intervention will be assessed.