What Is the Superior Vena Cava?

The superior vena cava is a thick and short venous trunk formed by the left and right head and arm veins converging at the rear of the junction of the right first rib cartilage and the sternum, and injected into the right atrium down to the lower edge of the third sternum joint.

The superior vena cava is a thick and short venous trunk formed by the left and right head and arm veins converging at the rear of the junction of the right first rib cartilage and the sternum, and injected into the right atrium down to the lower edge of the third sternum joint.

Chinese name

Superior vena cava

Foreign name

precava; venae cava superior;

Location

Superior mediastinum right front

Structure

Left and right head arm veins in right 1 thorax

Features

Collect upper body venous blood

End point

Right atrium

Overview of superior vena cava :

Mainly collected venous blood from head and neck, upper limbs and chest wall. When the superior vena cava is compressed, it can produce facial and upper limb edema, and the neck, upper limbs, and chest wall veins are swollen, which is called superior vena cava obstruction syndrome.

Superior vena cava anatomy:

1 Superior vena cava 1, superior vena cava:

The venous blood collected from the upper body was returned to the right atrium. It was a thick and short venous trunk, which was formed by the confluence of the left and right nameless (head and arm) veins behind the right thoracic rib joint. Vertically descend along the right side of the ascending aorta, and inject it into the upper right atrium to the height of the lower edge of the right thoracic rib joint 3. The total length of the superior vena cava is about 7 cm, without valves, and slightly convex to the right. The anterior septal thymus or adipose tissue and part of the right pleura are adjacent to the anterior chest wall. The rear is the right lung root. The left side abuts the ascending aorta, and on the right side there is a part of the right pleura and the phrenic nerve. An odd vein was injected into the right atrium. The lower section is located in the fibrous pericardium, and the front and sides are covered by the serous layer of the pericardium.

The superior vena cava and its branches constitute the superior vena cava system. All veins from the head and neck, upper limbs, and chest (except the heart) belong to the superior vena cava system, and are finally injected into the right atrium through the superior vena cava.

2 Superior vena cava 2 and inferior vena cava:

The inferior vena cava collects venous blood from the lower body and returns to the right atrium, which is the largest venous trunk in the human body. The 4th to 5th lumbar vertebrae are formed by confluence of the left and right common iliac veins. It rises on the right side of the abdominal aorta, passes through the vena cava fossa of the liver, and then penetrates the vena cava hole of the liver up to the thorax, and is injected into the lower posterior portion of the right atrium. There is a less obvious inferior vena cava valve at the front left of the entrance.

The inferior vena cava is adjacent to the right common iliac artery, the small intestinal mesentery, the right internal spermatic artery, the third segment of the duodenum, the pancreas, the portal vein, and the liver; Arteries, right lumbar artery, right adrenal artery, and right inferior iliac artery are adjacent; the lower left side is accompanied by the abdominal aorta, and the upper side is adjacent to the hepatic tail lobe and the right heel.

The inferior vena cava and its branches form the inferior vena cava system. All veins from the lower limbs, pelvis and abdomen belong to the inferior vena cava system, and they are finally injected into the right atrium through the inferior vena cava.

3 Superior vena cava 3. Right ventricle:

The right ventricle has a triangular pyramid shape with a bottom to right atrium opening and a pointed downward. In the ventricular cavity, there is a muscular bulge from the right atrioventricular vent to the pulmonary vent, called the supraventricular condyle. This case divides the right ventricle into the inflow and outflow tracts.

The inflow tract is the main part of the right ventricle, and there are many intersecting muscular bulges on the inner surface of the wall called the meat column. There are several thick and tapered meat columns called papillary muscles, which are generally three in front, back and medial. The entrance of the inflow tract is the right atrioventricular port, and there are three approximately triangular valves at the anterior, posterior, and medial edges of the port, called the tricuspid valve. The bottom of each valve is attached to the fibrous annulus (cardiac bone) around the right ventricular ostium, and its tip, or free edge, is connected to two adjacent papillary muscles by tendon cords. When the ventricle contracts, blood pushes the valve to close the atrioventricular opening. Due to the contraction of the papillary muscles and the tension of the chordae, the valve does not turn into the right atrium, prevents the blood from flowing backward into the atrium, and ensures the directional flow of blood. Any dysfunction such as valves, chordae, papillary muscles, and fibrous rings will have a serious impact on hemodynamics.

The outflow tract is the protruding part of the right ventricle to the upper left, which is called the arterial cone or funnel, and the inner surface of the wall is smooth and meatless. The outlet of the outflow tract is the pulmonary artery. There are three half-moon-shaped valves on the periphery of the mouth, called pulmonary valves. The free edge of the valve coincides with the direction of blood flow and faces the pulmonary artery. When the ventricle dilates, the valve that has been forced into the pulmonary artery presses the valve countercurrently, closing the free edges of the three valves to close the pulmonary artery opening to prevent blood from flowing back to the right ventricle.