The relationship between upper trapezius muscle length and upper quadrant neural tissue extensibility.

The upper trapezius muscle and the nerves of the brachial plexus share common anatomical locations and orientations. Whether upper trapezius muscle length measurements could be influenced by upper quadrant neural tissue extensibility was the question investigated in this paper. Two groups of normal subjects were studied, one with lesser and one with greater upper quadrant neural extensibility, measured by the upper limb tension test. Results indicated that those with decreased neural extensibility had significantly less measured length of the upper trapezii. These results should direct clinicians to assess neural tissue extensibility prior to interpreting the results of length tests of the upper trapezius muscle.