Yudu - sportEX medicine - 1999-2010

or visible fullness with a loss of the normal axillary concavity should alert the clinician to the possible presence of the arch of Langer (25,26). Cadaver studies report the presence of the arch of Langer in 6–11.5% of subjects (27). Although case reports have

described clinically plausible reasonable mechanisms of axillary artery injury, as outlined above, no experimental research has studied these postulations. Recent research by our team investigated the effects of glenohumeral anterior translation on ultrasonically determined blood-flow

characteristics at the third portion of the axillary artery (24). Comparison between baseline measurements and measurements with application of an anterior accessory glide at the glenohumeral joint revealed a statistically significant increase in peak systolic velocity (P<0.05) and a statistically significant decrease in arterial diameter (P<0.01) (both results indicative of arterial compression). Furthermore, when subjects were subdivided into ‘compressors’ and ‘non-compressors’, determined by the degree of axillary artery

compression observed on performance of the hyperabduction manoeuvre, a statistically significant difference was found between the groups (P<0.05), with ‘compressors’ demonstrating greater ranges of anterior translation. This research offers some support to the clinical suspicion that excessive translation at the glenohumeral joint impacts on axillary artery haemodynamics. More investigations are required to determine the contribution of excessive glenohumeral translation on axillary artery injury.

QUADILATERAL SPACE SYNDROME (POSTERIOR HUMERAL CIRCUMFLEX ARTERY) The quadrilateral space is bordered on the lateral aspect by the neck of the humerus, medially by the long head of triceps, superiorly by teres minor, and inferiorly by teres major (Figs. 5 & 6). At the third portion of the axillary

artery, the posterior and anterior humeral circumflex arteries branch to loop around the neck of the humerus (Figs. 7-9). The posterior humeral circumflex artery (PHCA) and the axillary nerve traverse through the quadrilateral space and are vulnerable to compression in the overhead- throwing athlete (28–33). Manoeuvres incorporating abduction and external rotation at the glenohumeral joint, such as the hyperabduction manoeuvre, are thought to compress the artery and most likely simultaneously compress the axillary nerve. Pain is poorly localised over the shoulder, with discrete point tenderness in the quadrilateral space, close to the insertion of teres minor, and paraesthesia may be present in a non- dermatomal pattern (although, if the axillary nerve is affected, anaesthesia may present on a small patch of skin overlying deltoid insertion) (34). As with the axillary artery, repetitive forceful overhead arm motion combined with excessive translation of the humerus on the glenoid is thought to be the mechanism of injury (5). In addition, it is speculated that

forceful overhead motion can cause a traction effect on the PHCA junction with the axillary artery, leading to a stretching injury and resulting in

Figure 5: Quadrilateral space without long head of triceps

ANTERIOR

CIRCUMFLEX ARTERY

Figure 6: Quadrilateral space with long head of triceps

POSTERIOR CIRCUMFLEX ARTERY

Figure 7: Anterior circumflex artery originating from axillary artery

thrombus or aneurysm formation at that site (5,33). As with the hyperabduction

syndrome, the true prevalence of quadrilateral space syndrome is unknown. It is believed that many such injuries go undiagnosed due to poor sensitivity of tests and a lack of clinical suspicion towards vascular pathology in healthy athletes (35).

Figure 9: Posterior circumflex artery passing through the quadrilateral space

sportEX medicine 2009;39(Jan):22-26

Figure 8: Posterior circumflex artery originating from axillary artery