Human Veins: Anatomy and Venous Drainage Pathways

Understanding Human Veins: Key Drainage Pathways

Veins: The superior vena cava drains the head, neck, upper limbs, and thorax. The inferior vena cava receives blood from the lower limbs, pelvis, and abdomen.

Pulmonary and Cardiac Veins

Pulmonary Veins

There are two pulmonary veins for each lung, and they notably lack valves.

Veins of the Heart

The primary vein of the heart is the coronary sinus.

Detailed Anatomy of Major Veins

Superior Vena Cava

The superior vena cava is formed in the superior mediastinum by the union of the two brachiocephalic veins. It typically measures 2 cm in diameter and 7 cm in length.

Branches of the Superior Vena Cava

• The azygos vein
• Pericardial veins
• Mediastinal veins

Brachiocephalic Veins

These veins represent the union of veins from the upper limbs, head, and neck. They are two thick trunks formed by the union of the internal jugular and subclavian veins.

Relations of Brachiocephalic Veins

• The right brachiocephalic vein measures approximately 3 cm.
• The left brachiocephalic vein measures approximately 6 cm.

Branches of Brachiocephalic Veins

• Inferior thyroid vein
• Thymic veins
• Pericardial veins
• Pericardiacophrenic veins
• Mediastinal veins
• Bronchial veins
• Tracheal veins
• Esophageal veins

Vertebral Vein

The vertebral vein receives the occipital vein in the suboccipital triangle and usually empties into the external jugular vein. At its terminal end, it connects with the anterior vertebral vein and deep cervical vein.

Accessory Vertebral and Internal Thoracic Veins

Accessory Vertebral Vein

The accessory vertebral vein empties into the brachiocephalic vein.

Internal Thoracic Veins

The internal thoracic veins drain the superior epigastric veins, subcutaneous abdominal veins, and superior musculophrenic intercostal veins.

Internal Jugular Vein

The internal jugular vein receives blood from the brain, face, and neck. It is located posterior and lateral to the internal carotid and common carotid arteries, ending at the root of the neck by joining the subclavian vein to form the brachiocephalic vein.

Relationships of the Internal Jugular Vein

It is covered by the sternocleidomastoid (ECOM), digastric, and omohyoid muscles.

Branches of the Internal Jugular Vein

Along its course, it receives:

• Veins of the cochlear canaliculus
• Pharyngeal veins
• Meningeal veins
• Lingual vein
• Superior thyroid vein
• Middle thyroid vein
• Facial vein (which receives external nasal veins, superior and inferior eyelid veins, superior and inferior labial veins)
• Superficial temporal vein
• Maxillary vein

External Jugular Vein

The external jugular vein results from the union of the posterior branch of the retromandibular vein and the posterior auricular vein. It typically empties into the subclavian vein or, less commonly, the internal jugular vein.

Subclavian Vein