Thoracic outlet syndrome refers to a group of conditions that develop when the blood vessels or nerves in the thoracic outlet become compressed. The thoracic outlet is the narrow space between your collarbone and first rib. Blood vessels, nerves, and muscles that extend from the back to the arms pass through this area. If the space in the thoracic outlet is too narrow, these structures can become compressed. The increased pressure on the blood vessels and nerves may cause pain in your shoulders, neck, and arms. It can also cause numbness or tingling in your hands.
pain in parts of the neck, shoulder, arm, or hand
numbness in the forearm and fingers
weakness of the hand
Compressed blood vessels can cause:
swelling of the arm
redness of the arm
hands or arms that feel cold to the touch
hands or arms that become easily fatigued
You may also find it difficult to lift objects above your head. You might also have a limited range of motion in your shoulders and arms.