There are many diseases that cause this syndrome, such as rib fracture, rickets, thoracic outlet syndrome and sternal fracture, etc. Therefore, patients need to be examined in detail when treating shackle chest, so that the cause of shackle chest can be determined in time, and the symptomatic treatment can be cured as soon as possible. The examination of thoracic outlet syndrome caused by shackle chest: 1, Doppler ultrasonography and photoelectric flowmeter detection: can estimate the vascular compression, but is not a specific examination method. The surgical efficacy can be estimated according to the preoperative and postoperative blood flow. 2.Angiography: used to clarify the nature of the lesion and exclude other vascular lesions. 3.The conduction velocity of the ulnar nerve is measured: the conduction velocity of the ulnar nerve is measured at the thoracic outlet, elbow and forearm respectively. Normal thoracic outlet is 72m/s, elbow 55m/s and forearm 59m/s. In patients with thoracic outlet syndrome, the conduction velocity of the ulnar nerve at the thoracic outlet is reduced to 32-65m/s, with an average of 53m/s. 4. Upper limb abduction test: the upper limb is abducted at 90°, 135° and 180°, with the hand externally rotated and the neck in the extended position. Make the subclavian neurovascular tight bundle pressure below the stop of pectoralis minor muscle and at the gap between the clavicle and the first rib, and feel the pain or increased pain in the neck and shoulder and upper limb. The radial artery pulsation is weakened or disappears, the blood pressure drops by 2.0 kPa (15 mmHg), and a systolic murmur is heard in the subclavian artery area.