Effect of muscle contraction induced by electrical stimulation of the long head triceps brachii muscle on the scapula position

Abstract

[Purpose] We examined the effect of muscle contraction induced by electrical stimulation of the long head of the triceps on scapular position. [Subjects and Methods] Twenty limbs of 10 healthy males were evaluated. The upper limb was set at horizontal flexion of 60° to the shoulder joint on a treatment table. Muscle contraction was induced by electrical stimulation of the long head of the triceps brachii, and radiographs were then obtained. The distances between rest and stimulation of the medial of the spina scapula and the spinal column, and the angulus inferior scapulae and the spinal column, and the change in the upper rotation angle of the scapula were measured on the radiographs. [Results] The distance between the angulus inferior scapulae and the spinal column, and the upper rotation angle of the scapula following electrical stimulation were significantly increased, compared to the measurements at rest. [Conclusion] Muscle contraction of the long head of the triceps may have induced abduction and upward rotation of the scapula.