Previous studies have reported that shear wave speed along muscle fibers is distinct from the speed across the fibers. Therefore, the shear speed may be a sensitive method to determine muscle fiber orientation in vivo. The purpose of this study is to develop a reproducible method to determine anisotropy in muscle fibers using Shear Wave Elastography (SWE). This technique was used to study myofascial trigger points (MTrPs) which are palpable tender nodules found in skeletal muscle. MTrPs are a characteristic finding in myofascial pain syndrome (MPS), a widely prevalent chronic pain condition. The relationship between MTrPs and the pathophysiology of MPS is still largely unknown. We hypothesized that muscle containing MTrPs have heterogeneous fiber orientation within the affected zone and surrounding areas compared to normal muscle.