Matt Harvey had his baseball season cut short after being diagnosed with Thoracic Outlet Syndrome. This season-ending injury involves compression at the thoracic inlet, often referred to as the superior thoracic aperture (or outlet).
In laymen’s terms, the thoracic inlet is a hole surrounded by a bony ring, through which several vital structures pass. The thoracic inlet is bounded by the T1 vertebra, the first pair of ribs laterally and the cartilage of the first rib and the superior border of the sternum.
Harvey had a rib removed to relieve him of pain. Some people diagnosed with Thoracic Outlet Syndrome, experience pain in their shoulders, neck and/or numbness in their fingers.