| Superior vena cava | |
|---|---|
 The superior vena cava drains from the left and right brachiocephalic veins into theright atrium | |
 | |
| Details | |
| Precursor | Common cardinal veins |
| Drains from | Left and rightbrachiocephalic veins |
| Source | Brachiocephalic vein,azygos vein |
| Drains to | Right atrium |
| Identifiers | |
| Latin | vena cava superior, vena maxima |
| MeSH | D014683 |
| TA98 | A12.3.03.001 |
| TA2 | 4745 |
| FMA | 4720 |
| Anatomical terminology | |
Thesuperior vena cava (SVC) is thesuperior of the twovenae cavae, the greatvenous trunks that return deoxygenatedblood from thesystemic circulation to theright atrium of theheart. It is a large-diameter (24 mm) short length (~7 cm) vein that receives venous return from the upper half of the body, above thediaphragm. Venous return from the lower half, below the diaphragm, flows through theinferior vena cava. The SVC is located in the anterior right superiormediastinum.[1] It is the typical site of central venous access via acentral venous catheter or aperipherally inserted central catheter. Mentions of "the cava" without further specification usually refer to the SVC.[citation needed]
The superior vena cava is formed by the left and rightbrachiocephalic veins, which receive blood from theupper limbs,head andneck, behind the lower border of the first rightcostal cartilage. It passes vertically downwards behind the first intercostal space and receives theazygos vein just before it pierces the fibrouspericardium opposite the right second costal cartilage and its lower part is intrapericardial. It then terminates in the upper and posterior part of the sinus venarum of the right atrium, at the upper right front portion of the heart. It is also known as the cranial vena cava in other animals. Novalve divides the superior vena cava from the right atrium.
The superior vena cava is made up of three layers, starting with the innermost endothelialtunica intima. The middle layer is thetunica media, composed of smooth muscle tissue, and the outermost and thickest layer is thetunica adventitia, composed of collagen and elastic connective tissue that allow for flexibility.[2][3] The tunica adventitia contains three zones, with the middle zone consisting of few smooth muscle fibers; this differs from the longitudinal bundles of smooth muscle found in the same zone of the inferior vena cava.[4]
The most commonanatomical variation is apersistent left superior vena cava. In persons with a persistent left superior vena cava, the right superior vena cava may be normal, small or absent, with or without an anterior communicating vein. This variation is present in less than 0.5% of the general population, but in up to 10% in patients withcongenital heart disease.[5]
Superior vena cava obstruction refers to a partial or complete obstruction of the superior vena cava, typically in the context ofcancer such as acancer of the lung,metastatic cancer, orlymphoma. Obstruction can lead to enlarged veins in the head and neck, and may also cause breathlessness, cough, chest pain, and difficulty swallowing.Pemberton's sign may be positive. Tumours causing obstruction may be treated withchemotherapy and/orradiotherapy to reduce their effects, andcorticosteroids may also be given.[6]
Intricuspid valveregurgitation, these pulsations are very strong.[clarification needed]
Novalve divides the superior vena cava from the right atrium. As a result, the (right) atrial and (right) ventricular contractions are conducted up into theinternal jugular vein and, through thesternocleidomastoid muscle, can be seen as thejugular venous pressure.
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