Anterior Translation at the Glenohumeral Joint

Background: Lesions to the axillary artery are reported in overhead athletes. One speculated cause is repeated transient compression by the humeral head due to excessive laxity at the glenohumeral joint. Hypotheses: (1) Anterior translation of the glenohumeral joint alters axillary artery diameter and blood flow characteristics, and (2) individuals demonstrating inducible axillary artery compression with the arm in an overhead position (as indicated by diameter and blood flow characteristics) will demonstrate greater magnitudes of anterior translation. Study Design: Descriptive laboratory study. Methods: After receiving ethical approval and screening for problematic conditions/injuries, 26 subjects were tested (10 men and 16 women; mean age [standard deviation], 25 years [4]). Axillary artery diameter and peak systolic velocity were measured with B-mode and Doppler ultrasound before, during, and after glenohumeral anterior translation at 90 ° of abduction, 60 ° of external rotation, and 30 ° of horizontal flexion, and at baseline and a simulated overhead throwing position (120 ° of abduction, 90 ° of external rotation, and 30 ° of horizontal extension). The magnitude of anterior translation was captured with B-mode ultrasound using a posterior transverse approach. Results: Application of the glide resulted in a significant (F 2,21 = 9.965, P = .001) reduction in axillary artery diameter and a significant increase in peak systolic velocity (F 2,21 = 5.286, P = .014). Subjects demonstrating clinically significant levels of axillary artery compression ( > 50% reduction in vessel diameter with the arm in the overhead throwing position) exhibited significantly ( t = −2.260, P = .040) greater ranges of anterior translation at the glenohumeral joint than the 9 subjects who exhibited < 10% reduction in arterial diameter. Conclusions: This investigation provides the first empirical support for the clinical opinion that glenohumeral anterior translation could be a mechanism for inducible axillary artery compression. Clinical Relevance: The response of axillary artery hemodynamics in normal, healthy individuals is the first step in the process of determining whether the finding of inducible axillary artery compression in overhead athletes with arterial pathology is related to glenohumeral translation. Keywords: axillary artery ultrasound glenohumeral instability vascular compression syndrome