Emidio Pacecca 27 March 2019 Thoracic Outlet Syndrome - A different shoulder diagnosis Emidio Pacecca 27 March 2019 The ‘Thoracic Outlet’ describes the compression of nerves (brachial plexus), arteries and veins resulting in pain, and altered sensations in and around the neck, chest and shoulder area. This is a rare syndrome only affecting 8% of the population.