The subclavian vein is a paired large

vein Veins are blood vessels in humans and most other animals 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 oxygenat ...

, one on either side of the body, that is responsible for draining

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

from the upper extremities, allowing this blood to return to the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...

. The left subclavian vein plays a key role in the absorption of

lipids Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...

, by allowing products that have been carried by

lymph Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues ...

in the

thoracic duct In human anatomy, the thoracic duct is the larger of the two lymph ducts of the lymphatic system. It is also known as the ''left lymphatic duct'', ''alimentary duct'', ''chyliferous duct'', and ''Van Hoorne's canal''. The other duct is the righ ...

to enter the bloodstream. The

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...

of the subclavian veins is approximately 1–2 cm, depending on the individual.

Structure

Each subclavian vein is a continuation of the

axillary vein In human anatomy, the axillary vein is a large blood vessel that conveys blood from the lateral aspect of the thorax, axilla (armpit) and upper limb toward the heart. There is one axillary vein on each side of the body. Structure Its origin ...

and runs from the outer border of the

first rib The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a semi ...

to the medial border of

anterior scalene muscle The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the anterior scalene, middle scalene, and posterior scalene. They are innervated by the third to the eight cervical spinal nerves (C3-C8). The anterior and ...

. From here it joins with the

internal jugular vein The internal jugular vein is a paired jugular vein that collects blood from the brain and the superficial parts of the face and neck. This vein runs in the carotid sheath with the common carotid artery and vagus nerve. It begins in the poste ...

to form the

brachiocephalic vein The left and right brachiocephalic veins (previously called innominate veins) are major veins in the upper chest, formed by the union of each corresponding internal jugular vein and subclavian vein. This is at the level of the sternoclavicular j ...

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

venous angle The venous angle, also known as Pirogoff's angle and in Latin as angulus venosus, is the junction where the internal jugular (Latin: ''v. jugularis interna'') and subclavian (Latin: ''v. subclavia'') veins at each side of the neck merge to form t ...

. The subclavian vein follows the subclavian artery and is separated from the subclavian artery by the insertion of anterior scalene. Thus, the subclavian vein lies anterior to the anterior scalene while the subclavian artery lies posterior to the anterior scalene (and anterior to the middle scalene).

Function

The

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

. It carries

(water and solutes) from the lymphatic system, as well as chylomicrons or

chyle Chyle (from the Greek word χυλός ''chylos'', "juice") is a milky bodily fluid consisting of lymph and emulsified fats, or free fatty acids (FFAs). It is formed in the small intestine during digestion of fatty foods, and taken up by lymph v ...

, formed in the

intestines The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

from dietary fat and

, allowing these to enter the bloodstream; the products of fats and lipids can then be carried by the bloodstream to the

hepatic portal vein The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approx ...

, and then finally to the liver. Consequently, the left subclavian vein plays a key role in the absorption of these fats and lipids. The

right lymphatic duct The right lymphatic duct is an important lymphatic vessel that drains the right upper quadrant of the body. It forms various combinations with the right subclavian vein and right internal jugular vein. Structure The right lymphatic duct course ...

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

Clinical relevance

Central venous lines

As the subclavian vein is large, central and relatively superficial, the right subclavian vein is often used to place

central venous lines A central venous catheter (CVC), also known as a central line(c-line), central venous line, or central venous access catheter, is a catheter placed into a large vein. It is a form of venous access. Placement of larger catheters in more centra ...

. It is less commonly used than other approaches, such as the right

, due to the risk of

pneumothorax A pneumothorax is an abnormal collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and shortness of breath. In a minority of cases, a one-way valve i ...

haemothorax A hemothorax (derived from hemo- lood+ thorax hest plural ''hemothoraces'') is an accumulation of blood within the pleural cavity. The symptoms of a hemothorax may include chest pain and difficulty breathing, while the clinical signs may incl ...

, and

puncture Puncture, punctured or puncturing may refer to: * a flat tyre in British English (US English "flat tire" or just "flat") * a penetrating wound caused by pointy objects as nails or needles * Lumbar puncture, also known as a spinal tap * Punctu ...

of the accompanying subclavian artery.

Thoracic outlet syndrome

The subclavian vein may be blocked during thoracic outlet syndrome. This can lead to arm swelling, pain, and cyanosis. The cause of the thoracic outlet syndrome, whether a

thrombus A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of ...

or external pressure, must be reversed urgently.

Etymology

''Sub'' (below), and ''clavian'' (pertaining to the

clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the r ...

Disorders

Paget–Schroetter disease Paget–Schroetter disease (also known as venous thoracic outlet syndrome) is a form of upper extremity deep vein thrombosis (DVT), a medical condition in which blood clots form in the deep veins of the arms. These DVTs typically occur in the axi ...

includes the thrombosis of the subclavian veins, in this case usually caused by exercise-induced strains.

Additional images

File:First rib Gray.png, Peculiar ribs. File:Venenwinkel.png, The venæ cavæ and azygos veins, with their tributaries. File:Gray599.png, The thoracic and right lymphatic ducts. File:Gray1178.png, The thymus of a full-term infant, exposed in situ. File:Slide9a.JPG, Subclavian vein File:Slide7d.JPG, Subclavian vein - right view File:Slide5dj.JPG, Subclavian vein File:Slide15d.JPG, Subclavian vein

References

{{Authority control Veins of the torso