The subclavian vein is a large blood vessel that arises from the axillary vein. It is one of the deep veins found on each side of the neck.

The subclavian vein originates at the outer border of the first rib, passes within the subclavian groove (on the 1st rib), then laterally to the medial border of the anterior scalene muscle. At this point, the subclavian vein joins with the internal jugular vein to form the brachiocephalic vein.

The main tributaries of the subclavian vein are:

• External jugular vein
• Dorsal scapular vein
• Anterior jugular veins (occasionally)

Also, the right subclavian vein receives the right lymphatic duct, while the left subclavian vein receives the thoracic duct.

The subclavian vein collects deoxygenated blood from the upper extremities and the pectoral (shoulder) girdle.

The brachiocephalic vein is a vessel formed by the union of the internal jugular vein and subclavian vein.

The right and left brachiocephalic veins arise asymmetrically. On the right side, the brachiocephalic vein originates behind the sternal end of the right clavicle, descends vertically and joins the left brachiocephalic vein to form the superior vena cava, behind the first right costal cartilage.

On the left side, the brachiocephalic vein starts from the left sternoclavicular joint, it passes medially, slightly descends obliquely to the first right costal cartilage and joins the right brachiocephalic vein, as mentioned before.

The main tributaries of the brachiocephalic vein are:

• Vertebral vein
• Inferior thyroid vein
• Internal thoracic vein
• Superior intercostal vein
• Supreme intercostal vein
• Pericardial veins
• Thymic veins

The brachiocephalic vein collects venous blood from the head, neck, upper limbs, part of the thorax, and mediastinum.