Thoracic outlet syndrome (TOS) is a condition whereby symptoms are produced (such as numbness in fingers, pain in shoulder, arm, and neck) due to compression of nerves and/or blood vessels in the upper chest. The passageway for these nerves and blood vessels to exit the chest and supply the upper extremities is referred to as the thoracic outlet.

https://www.medicinenet.com/thoracic_outlet_syndrome/article.htm