Jugular Veins: Veins in the neck which drain the brain, face, and neck into the brachiocephalic or subclavian veins.Veins: The vessels carrying blood away from the capillary beds.Catheterization, Central Venous: Placement of an intravenous CATHETER in the subclavian, jugular, or other central vein.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.Saphenous Vein: The vein which drains the foot and leg.Portal Vein: A short thick vein formed by union of the superior mesenteric vein and the splenic vein.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.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.Varicose Veins: Enlarged and tortuous VEINS.Cerebral Veins: Veins draining the cerebrum.Pulmonary Veins: The veins that return the oxygenated blood from the lungs to the left atrium of the heart.Catheters, Indwelling: Catheters designed to be left within an organ or passage for an extended period of time.Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.Cranial Sinuses: Large endothelium-lined venous channels situated between the two layers of DURA MATER, the endosteal and the meningeal layers. They are devoid of valves and are parts of the venous system of dura mater. Major cranial sinuses include a postero-superior group (such as superior sagittal, inferior sagittal, straight, transverse, and occipital) and an antero-inferior group (such as cavernous, petrosal, and basilar plexus).Venous Valves: Flaps within the VEINS that allow the blood to flow only in one direction. They are usually in the medium size veins that carry blood to the heart against gravity.Fusobacterium necrophorum: A species of gram-negative, non-spore-forming bacteria isolated from the natural cavities of man and other animals and from necrotic lesions, abscesses, and blood.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.Fusobacterium Infections: Infections with bacteria of the genus FUSOBACTERIUM.Mesenteric Veins: Veins which return blood from the intestines; the inferior mesenteric vein empties into the splenic vein, the superior mesenteric vein joins the splenic vein to form the portal vein.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Lemierre Syndrome: A superinfection of the damaged oropharyngeal mucosa by FUSOBACTERIUM NECROPHORUM leading to the secondary septic THROMBOPHLEBITIS of the internal jugular vein.Renal Veins: Short thick veins which return blood from the kidneys to the vena cava.Umbilical Veins: Venous vessels in the umbilical cord. They carry oxygenated, nutrient-rich blood from the mother to the FETUS via the PLACENTA. In humans, there is normally one umbilical vein.Iliac Vein: A vein on either side of the body which is formed by the union of the external and internal iliac veins and passes upward to join with its fellow of the opposite side to form the inferior vena cava.Azygos Vein: A vein which arises from the right ascending lumbar vein or the vena cava, enters the thorax through the aortic orifice in the diaphragm, and terminates in the superior vena cava.Venae Cavae: The inferior and superior venae cavae.Thrombophlebitis: Inflammation of a vein associated with a blood clot (THROMBUS).Hepatic Veins: Veins which drain the liver.Popliteal Vein: The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein.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.Sheep: Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.Venous Pressure: The blood pressure in the VEINS. It is usually measured to assess the filling PRESSURE to the HEART VENTRICLE.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.Amnesia, Transient Global: A syndrome characterized by a transient loss of the ability to form new memories. It primarily occurs in middle aged or elderly individuals, and episodes may last from minutes to hours. During the period of amnesia, immediate and recent memory abilities are impaired, but the level of consciousness and ability to perform other intellectual tasks are preserved. The condition is related to bilateral dysfunction of the medial portions of each TEMPORAL LOBE. Complete recovery normally occurs, and recurrences are unusual. (From Adams et al., Principles of Neurology, 6th ed, pp429-30)Neck: The part of a human or animal body connecting the HEAD to the rest of the body.Vena Cava, Superior: The venous trunk which returns blood from the head, neck, upper extremities and chest.Venous Insufficiency: Impaired venous blood flow or venous return (venous stasis), usually caused by inadequate venous valves. Venous insufficiency often occurs in the legs, and is associated with EDEMA and sometimes with VENOUS STASIS ULCERS at the ankle.Polytetrafluoroethylene: Homopolymer of tetrafluoroethylene. Nonflammable, tough, inert plastic tubing or sheeting; used to line vessels, insulate, protect or lubricate apparatus; also as filter, coating for surgical implants or as prosthetic material. Synonyms: Fluoroflex; Fluoroplast; Ftoroplast; Halon; Polyfene; PTFE; Tetron.Carotid Arteries: Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.Valsalva Maneuver: Forced expiratory effort against a closed GLOTTIS.Splenic Vein: Vein formed by the union (at the hilus of the spleen) of several small veins from the stomach, pancreas, spleen and mesentery.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Catheterization, Peripheral: Insertion of a catheter into a peripheral artery, vein, or airway for diagnostic or therapeutic purposes.Vascular Grafting: Surgical insertion of BLOOD VESSEL PROSTHESES, or transplanted BLOOD VESSELS, or other biological material to repair injured or diseased blood vessels.Central Venous Pressure: The blood pressure in the central large VEINS of the body. It is distinguished from peripheral venous pressure which occurs in an extremity.Arteriovenous Shunt, Surgical: Surgical shunt allowing direct passage of blood from an artery to a vein. (From Dorland, 28th ed)Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Graft Occlusion, Vascular: Obstruction of flow in biological or prosthetic vascular grafts.Venous Cutdown: Creation of a small incised opening in a vein to permit the passage of a needle or cannula for withdrawal of blood, administration of medication, or in diagnostic or therapeutic catheterization. (Dorland, 28th ed.; Stedman, 26th ed.)Arteriovenous Fistula: An abnormal direct communication between an artery and a vein without passing through the CAPILLARIES. An A-V fistula usually leads to the formation of a dilated sac-like connection, arteriovenous aneurysm. The locations and size of the shunts determine the degree of effects on the cardiovascular functions such as BLOOD PRESSURE and HEART RATE.Central Venous Catheters: Catheters that are inserted into a large central vein such as a SUBCLAVIAN VEIN or FEMORAL VEIN.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Constriction, Pathologic: The condition of an anatomical structure's being constricted beyond normal dimensions.Punctures: Incision of tissues for injection of medication or for other diagnostic or therapeutic procedures. Punctures of the skin, for example may be used for diagnostic drainage; of blood vessels for diagnostic imaging procedures.Retinal Vein: Central retinal vein and its tributaries. It runs a short course within the optic nerve and then leaves and empties into the superior ophthalmic vein or cavernous sinus.Hyperplasia: An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.Blood Vessel Prosthesis: Device constructed of either synthetic or biological material that is used for the repair of injured or diseased blood vessels.Vascular Malformations: A spectrum of congenital, inherited, or acquired abnormalities in BLOOD VESSELS that can adversely affect the normal blood flow in ARTERIES or VEINS. Most are congenital defects such as abnormal communications between blood vessels (fistula), shunting of arterial blood directly into veins bypassing the CAPILLARIES (arteriovenous malformations), formation of large dilated blood blood-filled vessels (cavernous angioma), and swollen capillaries (capillary telangiectases). In rare cases, vascular malformations can result from trauma or diseases.Progesterone: The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.Vena Cava, Inferior: The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Carotid Artery, Common: The two principal arteries supplying the structures of the head and neck. They ascend in the neck, one on each side, and at the level of the upper border of the thyroid cartilage, each divides into two branches, the external (CAROTID ARTERY, EXTERNAL) and internal (CAROTID ARTERY, INTERNAL) carotid arteries.Vascular Surgical Procedures: Operative procedures for the treatment of vascular disorders.Estrus: The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.Glomus Jugulare: A nonchromaffin paraganglion located in the wall of the jugular bulb. The most common tumors of the middle ear arise from this tissue. (Lockard, Desk Reference for Neuroscience, 1992, p114)Injections, Intravenous: Injections made into a vein for therapeutic or experimental purposes.Foreign-Body Migration: Migration of a foreign body from its original location to some other location in the body.