Translational movement within the glenohumeral joint at different rotation velocities as seen by cine MRI.

Background: The glenohumeral joint is subjected to opposing forces when the direction of shoulder motion is changed, accelerating and decelerating to make the movements. The influence of motion velocity or acceleration on translation of the humeral head has not been evaluated although direction and distance of humeral head translation has been analyzed in real time in normal shoulders. We hypothesized that, in a normal shoulder, the humeral head does not deviate significantly or suddenly during active shoulder rotation regardless of motion velocity.

Motor control training for an amateur baseball pitcher with isolated paralysis of trapezius: a case report.

Study Design: Case report.

Background: A case of an athlete with accessory nerve injury has not been previously reported although there have been a number of case reports and case series of non-athletes with accessory nerve injury. This case study reports motor control intervention for an amateur baseball pitcher with isolated paralysis of the right trapezius who lost pitching control after changing his pitching technique.

Deviation of skin marker from bone target during movement of the scapula.

Background: Recording movement of the scapula by non-invasive techniques is fraught with technical difficulty. One convenient method involves placing a single marker on the skin overlying the acromion. The purpose of this study was to compare translatory discrepancies between marker and underlying bone for seven markers affixed to the skin overlying different parts of the scapula.