# What is the systemic veins?

Gray’s Anatomy (1918) describes the systemic veins as follows: The systemic veins may be arranged into three groups: (1) The veins of the heart.

## What it means

- The systemic veins may be arranged into three groups: (1) The veins of the heart. (2) The veins of the upper extremities, head, neck, and thorax, which end in the superior vena cava. (3) The veins of the lower extremities, abdomen, and pelvis, which end in the inferior vena cava. Coronary Sinus ( sinus coronarius ). — (VV. Cordis) —Most of the veins of the heart open into the coronary sinus. This is a wide venous channel about 2.25 cm.
- in length situated in the posterior part of the coronary sulcus, and covered by muscular fibers from the left atrium. It ends in the right atrium between the opening of the inferior vena cava and the atrioventricular aperture, its orifice being guarded by a semilunar valve, the valve of the coronary sinus ( valve of Thebesius ). Tributaries.
- —Its tributaries are the great, small, and middle cardiac veins, the posterior vein of the left ventricle, and the oblique vein of the left atrium, all of which, except the last, are provided with valves at their orifices.

## Sources

- [Gray's Anatomy of the Human Body (1918)](https://www.bartleby.com/lit-hub/anatomy-of-the-human-body/3-the-systemic-veins/)

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