The heart pumps oxygenated blood through the aorta to smaller arteries. After the blood supplies nutrients to vital organs, it returns through veins for reoxygenation in the lungs (Figures 1 and 2). Blood clots called deep vein thrombi (DVT) often develop in the deep leg veins. Pulmonary embolism (PE) occurs when clots break off from vein walls and travel through the heart to the pulmonary arte...

Superficial veins of the upper extremity are the primary location for placement of peripheral IV catheters (PIVC). It is believed that a significant portion of PIVCs placed may cross or abut valves and branching veins or occlude a significant portion of the vein, limiting the ability to aspirate blood from the PIVC. Two separate clinical investigations using ultrasound were performed to underst...

In 26 of 214 patients with erectile dysfunction and proved venous incompetence by cavernosography, an additional bidirectional Doppler ultrasound was performed also to demonstrate venous outflow disturbances. All except one leakage in the superficial and deep dorsal veins could be demonstrated as well as 4 of 6 cavernosum-glandular shunts. Bidirectional Doppler ultrasound visualized a continuou...

Under normal circumstances, blood collected from superficial venous capillaries is directed upward and inward via one-way valves into superficial veins. These in turn drain via perforator veins, which pass through muscle fascia into deeper veins buried under the fascia. Leakage in a valve causes retrograde flow back into the vein. Unlike deep veins which are thick-walled and confined by fascia,...

Acetylcholine (ACh) induces nasal congestion at low doses but decongestion at high doses. The current study investigated the vascular mechanisms underlying this biphasic nasal airway response in dogs. Collecting and outflow veins from anterior and posterior nasal venous systems and the septal mucosa (containing sinusoidal venous plexuses) were isolated. The in vitro isometric tension of the vas...

BACKGROUND Several studies have suggested an association between Chlamydophila pneumoniae (Cp) infection and atherosclerosis. A recent study detected Cp DNA in the saphenous vein of 12% of all patients before bypass grafting and in 38% of failed grafts. We used a system in which human veins were perfused with autologous blood under arterial pressure. MATERIALS AND METHODS Veins were surplus s...

PURPOSE To measure the in vivo blood velocity in human retinal veins using a laser speckle system. METHODS The system consists of a fundus camera, a diode laser, an image sensor, and a personal computer system. The fundus area, including a target retinal vein, is illuminated with a diode laser through a fundus camera and the laser speckle pattern is imaged onto the area sensor. From the time ...

The veins of the brain have no muscular tissue in their thin walls and possess no valves. They emerge from the brain and lie in the subarachnoid space. They pierce the arachnoid mater and the meningeal layer of the dura and drain into the cranial venous sinuses. The cerebral venous system can be divided into a superficial and a deep system. The superficial system comprises sagittal sinuses and ...

In man the portal circulation, being without major and macroscopic connection with systemic veins, has been hidden from the clinical investigator. Even the intravascular catheter has not invaded the duplex circulations feeding the liver, but only its drainage system. Thus circulatory inaccessability of the key digestive gland in man has left it mysterious, a metabolic sphinx. Surgeons, deleting...