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Applied Anatomy of the Great Veins

The great veins are slow in flow, low in pressure and have the ability to accommodate changing intra-vascular volumes. They can, of course, only transport that which they receive, and in the end the net outflow from the left heart has to equal the net return to the right heart. One of the functions of the venous system is to regulate blood volume, and by virtue of the capacitance of the venous system, it can “hold” on to blood by dilating, or it can supply the system with volume, by contracting. The great veins have been designed as pliable tubes to accommodate and transport these changing volumes. Thrombosis is the most common disease plaguing the great veins, particularly as venous access devices…

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Articles of Interest

An Overview of the Major Blood Vessels: The inferior vena cava (IVC)

The inferior vena cava is one of the largest veins in the human body and is a vital component of the circulatory system, responsible for returning deoxygenated blood from the lower half of the body to the heart. The IVC is formed by the confluence of the left and right common iliac veins, which drain blood from the lower limbs and pelvis. It ascends along the right side of the vertebral column, passes through the diaphragm, and empties into the right atrium of the heart, hence, it can be visualised and assessed during an echocardiogram.

Inferior Vena Cava

There are many physiologic variants of the IVC. Compared to the arterial system the venous system is much more susceptible to congenital malformations, many of which remain asymptomatic throughout a patient's life. If symptoms are present, they are often vague and include abdominal pain or low back pain.

Inferior Vena Cava (IVC)

The normal diameter of the IVC is 1.5 – 2.5cm – this varies depending on inspiration and expiration and also with the patient’s volume status. A diameter of <1cm indicates hypovolaemia, whereas >2.5cm suggests fluid overload. As the central venous pressure is normally very low (5-10mmHg), IVC aneurysms are exceptionally rare. The low pressure instead makes it vulnerable to obstruction, which can be due to internal occlusion by thrombosis or spreading cancer (“tumour thrombus”), or external compression by an aortic aneurysm, intra-abdominal malignancies, or a heavily pregnant uterus. As with the abdominal aorta, trauma to the IVC tends to be catastrophic with rapid exsanguination.

Superior and Inferior Venae Cavae

Due to the important role that the superior and inferior venae cavae play in circulation, problems arising with these large veins can have serious consequences. Since veins have relatively thin walls and the venous system is a low-pressure system, both venae cavae are subject to compression by surrounding tissues that swell. This compression inhibits blood flow and impacts proper heart function. The development of blood clots within the venae cavae can also impede or block blood from returning to the heart.

The Superior Vena Cava

The superior vena cava is classified as a large vein, with a wide diameter of up to 2cm and a length of approximately 7cm. It arises from the union of the left and right brachiocephalic veins, posterior to the first right costal cartilage. It descends vertically through the superior mediastinum, behind the intercostal spaces and to the right of the aorta and trachea.

Vena Cava Filters: Current Concepts and Controversies for the Surgeon

The development of modern endovenous vena caval filter interruption to mitigate the mortality and morbidity from deep venous thrombosis (DVT) and its associated pulmonary embolism (pulmonary embolus [PE]) is a journey that parallels the evolution of vascular and endovenous surgery, supported by historic developments in radiology and pharmacology.