The subclavian veins are two large vein

Vein

In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...

s, one on either side of the body. Their diameter is approximately that of the smallest finger.

Path

Each subclavian vein is a continuation of the axillary vein

Axillary vein

In human anatomy, the axillary vein is a large blood vessel that conveys blood from the lateral aspect of the thorax, axilla and upper limb toward the heart...

 and runs from the outer border of the first rib

First rib

The first rib is the most curved and usually the shortest of all the ribs; it is broad and flat, its surfaces looking upward and downward, and its borders inward and outward....

 to the medial

Anatomical terms of location

Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...

 border of anterior scalene muscle

Scalene muscles

The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the scalenus anterior, scalenus medius, and scalenus posterior.They are innervated by the spinal nerves C4-C6....

. From here it joins with the internal jugular vein

Internal jugular vein

The two internal jugular veins collect the blood from the brain, the superficial parts of the face, and the neck.-Path:On both sides and at the base of the brain, the inferior petrosal sinus and the sigmoid sinus join to form the internal jugular vein...

 to form the brachiocephalic vein

Brachiocephalic vein

The left and right brachiocephalic veins in the upper chest are formed by the union of each corresponding internal jugular vein and subclavian vein...

 (also known as "innominate vein"). The angle of union is termed the venous angle.

The subclavian vein follows the subclavian artery

Subclavian artery

In human anatomy, the subclavian arteries are two major arteries of the upper thorax , below the clavicle . They receive blood from the top of the aorta...

 and is separated posteriorly

Anatomical terms of location

Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...

 by the insertion of anterior scalene.

Lymph

The thoracic duct

Thoracic duct

In human anatomy, the thoracic duct of the lymphatic system is the largest lymphatic vessel in the body. It is also known as the left lymphatic duct, alimentary duct, chyliferous duct, and Van Hoorne's canal....

 drains into the left subclavian vein, near its junction with the left internal jugular vein

Internal jugular vein

The two internal jugular veins collect the blood from the brain, the superficial parts of the face, and the neck.-Path:On both sides and at the base of the brain, the inferior petrosal sinus and the sigmoid sinus join to form the internal jugular vein...

. It carries lymph

Lymph

Lymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary...

 (water and solutes) from the lymphatic system

Lymphatic system

The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...

, as well as chylomicrons or chyle

Chyle

Chyle is a milky bodily fluid consisting of lymph and emulsified fats, or free fatty acids . It is formed in the small intestine during digestion of fatty foods, and taken up by lymph vessels specifically known as lacteals...

, formed in the intestines from dietary fat and lipids.

The right lymphatic duct

Right lymphatic duct

The right lymphatic duct, about 1.25 cm. in length, courses along the medial border of the Scalenus anterior at the root of the neck. In most cases it ends in the right subclavian vein, at its angle of junction with the right internal jugular vein, although the termination can be variable, however...

drains its lymph into the junction of the right internal jugular vein, and the right subclavian vein.