Superior vena cava, brachiocephalic veins, jugular veins

Introduction

The superior vena cava (SVC), brachiocephalic veins, and jugular veins are essential components of the systemic venous system responsible for returning deoxygenated blood from the upper body to the heart. Their anatomical arrangement and clinical significance are important in various medical and surgical contexts.

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Superior Vena Cava

Structure and Course

The superior vena cava is a large, valveless vein formed by the union of the right and left brachiocephalic veins behind the lower border of the first right costal cartilage. It descends vertically along the right side of the superior mediastinum and terminates in the right atrium at the level of the third right costal cartilage.

Length: approximately 7 cm

Diameter: approximately 2 cm

Relations:

• Anterior: thymus (or remnant), right lung and pleura
• Posterior: right pulmonary artery, right bronchus
• Right: phrenic nerve
• Left: ascending aorta

The SVC receives tributaries, including the azygos vein (posteriorly) before entering the pericardial sac.

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Brachiocephalic Veins

Formation and Course

Each brachiocephalic vein is formed by the union of the subclavian vein and internal jugular vein behind the sternoclavicular joint.

Right brachiocephalic vein:

• Shorter and vertical
• Joins left vein to form SVC behind first right costal cartilage

Left brachiocephalic vein:

• Longer and more oblique
• Crosses midline anterior to the aortic arch branches (brachiocephalic trunk, left common carotid, left subclavian artery)

Both veins receive tributaries such as:

• Vertebral veins
• Internal thoracic veins
• Inferior thyroid veins

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Jugular Veins

Internal Jugular Vein (IJV):

The internal jugular vein drains blood from the brain, face, and neck. It begins at the jugular foramen as a continuation of the sigmoid sinus and descends within the carotid sheath lateral to the internal and common carotid arteries.

iIt joins the subclavian vein behind the sternoclavicular joint to form the brachiocephalic vein.

External Jugular Vein (EJV):

The external jugular vein forms near the angle of the mandible from the posterior division of the retromandibular vein and posterior auricular vein. It crosses the sternocleidomastoid superficially and empties into the subclavian vein.

It drains superficial structures of the scalp and face.

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Clinical Relevance

The superior vena cava and associated veins are significant landmarks in central venous catheterization, pacemaker lead insertion, and evaluation of superior vena cava syndrome (SVC obstruction causing venous congestion of the upper body).

Jugular veins provide access for central venous pressure measurement (via internal jugular) and are inspected clinically for signs of heart failure or raised right atrial pressure.

Thrombosis, catheter-related infections, or compression by tumors (e.g., lung cancer causing SVC syndrome) are important clinical considerations.

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Conclusion

The superior vena cava, brachiocephalic veins, and jugular veins play a critical role in venous return from the head, neck, and upper limbs. Their anatomical relationships are essential for clinical procedures and understanding pathologies affecting thoracic venous drainage.

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References

1. Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. 8th ed. Philadelphia: Wolters Kluwer; 2018.
2. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. Elsevier; 2016.
3. Netter FH. Atlas of Human Anatomy. 7th ed. Elsevier; 2019.

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