Subclavian Vein: The continuation of the axillary vein which follows the subclavian artery and then joins the internal jugular vein to form the brachiocephalic vein.Catheterization, Central Venous: Placement of an intravenous CATHETER in the subclavian, jugular, or other central vein.Jugular Veins: Veins in the neck which drain the brain, face, and neck into the brachiocephalic or subclavian veins.Axillary Vein: The venous trunk of the upper limb; a continuation of the basilar and brachial veins running from the lower border of the teres major muscle to the outer border of the first rib where it becomes the subclavian vein.Thoracic Outlet Syndrome: A neurovascular syndrome associated with compression of the BRACHIAL PLEXUS; SUBCLAVIAN ARTERY; and SUBCLAVIAN VEIN at the superior thoracic outlet. This may result from a variety of anomalies such as a CERVICAL RIB, anomalous fascial bands, and abnormalities of the origin or insertion of the anterior or medial scalene muscles. Clinical features may include pain in the shoulder and neck region which radiates into the arm, PARESIS or PARALYSIS of brachial plexus innervated muscles, PARESTHESIA, loss of sensation, reduction of arterial pulses in the affected extremity, ISCHEMIA, and EDEMA. (Adams et al., Principles of Neurology, 6th ed, pp214-5).Upper Extremity Deep Vein Thrombosis: DEEP VEIN THROMBOSIS of an upper extremity vein (e.g., AXILLARY VEIN; SUBCLAVIAN VEIN; and JUGULAR VEINS). It is associated with mechanical factors (Upper Extremity Deep Vein Thrombosis, Primary) secondary to other anatomic factors (Upper Extremity Deep Vein Thrombosis, Secondary). Symptoms may include sudden onset of pain, warmth, redness, blueness, and swelling in the arm.Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.Veins: The vessels carrying blood away from the capillary beds.Clavicle: A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone.Ribs: A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs.Brachiocephalic Veins: Large veins on either side of the root of the neck formed by the junction of the internal jugular and subclavian veins. They drain blood from the head, neck, and upper extremities, and unite to form the superior vena cava.Femoral Vein: The vein accompanying the femoral artery in the same sheath; it is a continuation of the popliteal vein and becomes the external iliac vein.Iothalamate Meglumine: A radiopaque medium used for urography, angiography, venography, and myelography. It is highly viscous and binds to plasma proteins.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Pacemaker, Artificial: A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).Saphenous Vein: The vein which drains the foot and leg.Hemothorax: Hemorrhage within the pleural cavity.Catheters, Indwelling: Catheters designed to be left within an organ or passage for an extended period of time.Vena Cava, Superior: The venous trunk which returns blood from the head, neck, upper extremities and chest.Portal Vein: A short thick vein formed by union of the superior mesenteric vein and the splenic vein.Decompression, Surgical: A surgical operation for the relief of pressure in a body compartment or on a body part. (From Dorland, 28th ed)Hydrothorax: A collection of watery fluid in the pleural cavity. (Dorland, 27th ed)Varicose Veins: Enlarged and tortuous VEINS.Catheterization: Use or insertion of a tubular device into a duct, blood vessel, hollow organ, or body cavity for injecting or withdrawing fluids for diagnostic or therapeutic purposes. It differs from INTUBATION in that the tube here is used to restore or maintain patency in obstructions.Equipment Failure: Failure of equipment to perform to standard. The failure may be due to defects or improper use.Pneumothorax: An accumulation of air or gas in the PLEURAL CAVITY, which may occur spontaneously or as a result of trauma or a pathological process. The gas may also be introduced deliberately during PNEUMOTHORAX, ARTIFICIAL.Electrodes, Implanted: Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.Ultrasonography, Doppler, Pulsed: Ultrasonography applying the Doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return.Arteriovenous Shunt, Surgical: Surgical shunt allowing direct passage of blood from an artery to a vein. (From Dorland, 28th ed)Pulmonary Veins: The veins that return the oxygenated blood from the lungs to the left atrium of the heart.Prosthesis Implantation: Surgical insertion of a prosthesis.Subclavian Steal Syndrome: A clinically significant reduction in blood supply to the BRAIN STEM and CEREBELLUM (i.e., VERTEBROBASILAR INSUFFICIENCY) resulting from reversal of blood flow through the VERTEBRAL ARTERY from occlusion or stenosis of the proximal subclavian or brachiocephalic artery. Common symptoms include VERTIGO; SYNCOPE; and INTERMITTENT CLAUDICATION of the involved upper extremity. Subclavian steal may also occur in asymptomatic individuals. (From J Cardiovasc Surg 1994;35(1):11-4; Acta Neurol Scand 1994;90(3):174-8)Iatrogenic Disease: Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment.Superior Vena Cava Syndrome: A condition that occurs when the obstruction of the thin-walled SUPERIOR VENA CAVA interrupts blood flow from the head, upper extremities, and thorax to the RIGHT ATRIUM. Obstruction can be caused by NEOPLASMS; THROMBOSIS; ANEURYSM; or external compression. The syndrome is characterized by swelling and/or CYANOSIS of the face, neck, and upper arms.Vascular Surgical Procedures: Operative procedures for the treatment of vascular disorders.Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.Constriction, Pathologic: The condition of an anatomical structure's being constricted beyond normal dimensions.