When the shoulder muscles in the chest are too weak to properly stabilize the collarbone, the bone can slip down and forward into the thoracic outlet, which is the narrow space between the collarbone and the first rib. The bone then puts pressure on the nerves and blood vessels in this small passageway, creating the various symptoms associated with thoracic outlet syndrome. These symptoms include an aching pain in the neck, shoulder, arm, or hand as well as pain, numbness, or tingling in the forearm and the fourth and fifth fingers of the hand. The pressure also can limit blood flow to and from the arm, causing swelling, redness, and fatigue. Many sufferers of thoracic outlet syndrome have trouble performing overhead activities. Some experience swelling or discoloration of the arm as well as a depression in the shoulder. This condition can result from a variety of conditions, including injury, disease, or congenital problems such as a deformity of the first rib. Additionally, poor posture and obesity may make symptoms worse. Treatments for thoracic outlet syndrome include physical therapy to strengthen the shoulder muscles that support the collar bone, a regimen of nonsteroidal anti-inflammatory medications such as naproxen and ibuprofen, a weight loss program to reduce stress to the shoulder muscles, lifestyle changes to eliminate situations and activities that aggravate symptoms, and finally, as a last resort, surgery.