Sonographic evaluation of the axillary artery during simulated overhead throwing arm positions

ObjectivesThe aim of this study was to determine changes in axillary artery diameter and peak systolic velocity in asymptomatic individuals during upper limb positioning commonly used to assess vascular pathology in athletes.DesignRepeated measures observational study.SettingPhysiology laboratory.ParticipantsSubjective and objective screening excluded individuals with past, or present, conditions related to neurovascular compression syndromes. Thirty-one subjects (21 females, 10 males; mean age: 25±4 years) were included in the final analysis.Main outcome measuresSonographically determined axillary artery diameter and peak systolic velocity, as well as symptom production, were recorded for a series of 12 randomised arm positions, incorporating varying degrees of abduction, external rotation, and horizontal flexion/extension.ResultsThe majority of arm positions revealed no change in artery diameter and peak systolic velocity. However, at the extreme of abduction, and arm positions incorporating 120° abduction, significant (p<0.0005) reductions in axillary artery diameter were noted. All mean results masked wide heterogeneity: 13% demonstrating a greater than 50% reduction in diameter, 10%, a doubling of peak systolic velocity, and 42%, reporting symptoms.ConclusionsThe number of individual clinically “positive” responses questions the specificity of individual diagnostic tests, such as the hyperabduction manoeuvre, and highlights the need to interpret test results in conjunction with the subjective assessment and other physical findings from the objective assessment.