Reciprocal compression between the axillary artery and brachial plexus.

Angiographic studies were performed on 60 of 394 patients diagnosed as having thoracic outlet syndrome. Ten of the patients studied angiographically presented with obstruction of contrast material in the axilla with refilling of the axillary artery through the external mammary and shoulder arteries. The obstruction was caused by lower trunk brachial plexus compression. This seldom known cause of hyperabduction syndrome occurred in 2.5 per cent of the patients examined for thoracic outlet syndrome. Surgical treatment consists of loosening the axillary artery by tying off the external mammary and circumflex arteries, followed by section and anastomosis of the axillary artery anteriorly to the brachial plexus. Angiography is considered a basic diagnostic procedure, mainly when concomitant compression occurs and gives good dynamic information on the location and importance of the compression.