PURPOSE: The objective of this study is to determine if pressures generated during manipulation are altered by hand configuration.
DESIGN/SETTING: Paired comparison of 2 different variable groups.
METHODS: Sixteen chiropractors provided 2 manipulations to a rigid surface using 2 hand configurations used commonly in clinical practice: arched and flat. Interposed between the hand and the rigid surface was a pressure sensor array and radiographic cassette. For each manipulation, pressures were recorded and a radiographic image was captured. Two radiologists then located the osseous features of the hand with respect to the sensor array.
RESULTS: In 15 of 16 cases, arched configurations produced peak pressures that corresponded to the radiographic location of the pisiform bone. In flat configurations, peak pressure migrated about the location of the hamate bone. Radiologists' agreement for bone position was high (kappa = 0.96). Measures of peak pressure, total pressure, and pressure distribution were statistically different between hand configurations.
CONCLUSIONS: The results of this study suggest that hand configuration influences the magnitude, location, and distribution of pressure generated by the hand during manipulation. This knowledge may have importance in understanding the relation among application parameters of manipulation, therapeutic benefit, and patient safety.
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