Veins are
blood vessel
The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...
s in humans and most other animals that carry
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 c ...
towards 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 t ...
. Most veins carry
deoxygenated 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 c ...
from the tissues back to the heart; exceptions are the
pulmonary
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of ...
and
umbilical vein
The umbilical vein is a vein present during fetal development that carries oxygenated blood from the placenta into the growing fetus. The umbilical vein provides convenient access to the central circulation of a neonate for restoration of blood v ...
s, both of which carry oxygenated blood to the heart. In contrast to veins,
arteries
An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
carry blood away from the heart.
Veins are less
muscular
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle ...
than arteries and are often closer to the skin. There are valves (called ''pocket valves'') in most veins to prevent
backflow
Backflow is a term in plumbing for an unwanted flow of water in the reverse direction. It can be a serious health risk for the contamination of potable water supplies with foul water. In the most obvious case, a toilet flush cistern and its wat ...
.
Structure
Veins are present throughout the body as tubes that carry blood back to the heart. Veins are classified in a number of ways, including superficial vs. deep, pulmonary vs. systemic, and large vs. small.
*
Superficial veins are those closer to the surface of the body, and have no corresponding arteries.
*
Deep vein
A deep vein is a vein that is deep in the body. This contrasts with superficial veins that are close to the body's surface.
Deep veins are almost always beside an artery with the same name (e.g. the femoral vein is beside the femoral artery). ...
s are deeper in the body and have corresponding arteries.
*
Perforator vein
Perforator veins are so called because they perforate the deep fascia of muscles, to connect the superficial veins to the deep veins where they drain.
Perforator veins play an essential role in maintaining normal blood draining. They have valves ...
s drain from the superficial to the deep veins.
These are usually referred to in the lower limbs and feet.
*
Communicating veins
Communicating veins are veins that communicate two different points of the venous system.
They can communicate the great saphenous vein with the small saphenous vein, (for example the Giacomini vein) or the superficial venous system with the de ...
are veins that directly connect superficial veins to deep veins.
*
Pulmonary vein
The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four ''main pulmonary veins'', two from each lung that drain into the left atrium of the heart. The pulmonary vei ...
s are a set of veins that deliver oxygenated blood from the
lung
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
s to the heart.
*
Systemic veins drain the tissues of the body and deliver deoxygenated blood to the heart.
Most veins are equipped with
one-way valve
A check valve, non-return valve, reflux valve, retention valve, foot valve, or one-way valve is a valve that normally allows fluid ( liquid or gas) to flow through it in only one direction.
Check valves are two-port valves, meaning they have ...
s, similar to a
Duckbill valve
A duckbill valve is a check valve, usually manufactured from rubber or synthetic elastomer, and has 2 (or more) flaps, usually shaped like the beak of a duck. It is commonly used in medical applications to prevent contamination due to backflow.
...
, to prevent blood flowing in the reverse direction.
Veins are translucent, so the color a vein appears from an organism's exterior is determined in large part by the color of
venous blood
Venous blood is deoxygenated blood which travels from the peripheral blood vessels, through the venous system into the right atrium of the heart. Deoxygenated blood is then pumped by the right ventricle to the lungs via the pulmonary artery wh ...
, which is usually dark red as a result of its low oxygen content. Veins appear blue because of the low oxygen level in the vein. The color of a vein can be affected by the characteristics of a person's skin, how much oxygen is being carried in the blood, and how big and deep the vessels are. When a vein is drained of blood and removed from an organism, it appears grey-white.
Venous system
![Major Veins](https://upload.wikimedia.org/wikipedia/commons/8/8d/Major_Veins.png)
The largest veins in the human body are the
venae cavae
In anatomy, the venae cavae (; singular: vena cava ; ) are two large veins (great vessels) that return deoxygenated blood from the body into the heart. In humans they are the superior vena cava and the inferior vena cava, and both empty into the ...
. These are two large veins which enter the right
atrium
Atrium may refer to:
Anatomy
* Atrium (heart), an anatomical structure of the heart
* Atrium, the genital structure next to the genital aperture in the reproductive system of gastropods
* Atrium of the ventricular system of the brain
* Pulmona ...
of the heart from above and below. The
superior vena cava
The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein th ...
carries blood from the arms and head to the right atrium of the heart, while the
inferior vena cava
The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...
carries blood from the legs and
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...
to the heart. The inferior vena cava is
retroperitoneal
The retroperitoneal space (retroperitoneum) is the anatomical space (sometimes a potential space) behind (''retro'') the peritoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on thei ...
and runs to the right and roughly parallel to the
abdominal aorta along the
spine. Large veins feed into these two veins, and smaller veins into these. Together this forms the venous system.
Whilst the main veins hold a relatively constant position, the position of veins person to person can display quite a lot of variation.
The
pulmonary vein
The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four ''main pulmonary veins'', two from each lung that drain into the left atrium of the heart. The pulmonary vei ...
s carry relatively oxygenated blood from the lungs to the heart. The
superior and
inferior venae cavae carry relatively deoxygenated blood from the upper and lower systemic circulations, respectively.
The
portal venous system
In the circulatory system of animals, a portal venous system occurs when a capillary bed pools into another capillary bed through veins, without first going through the heart. Both capillary beds and the blood vessels that connect them are con ...
is a series of veins or venules that directly connect two
capillary beds. Examples of such systems include 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
hypophyseal portal system
The hypophyseal portal system is a system of blood vessels in the microcirculation at the base of the brain, connecting the hypothalamus with the anterior pituitary. Its main function is to quickly transport and exchange hormones between the hypo ...
.
The
peripheral vein
The peripheral vascular system is the part of the circulatory system that consists of the veins and arteries not in the chest or abdomen (i.e. in the arms, hands, legs and feet). The peripheral arteries supply oxygenated blood to the body, a ...
s carry blood from the limbs and
hand
A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "h ...
s and
feet
The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...
.
Microanatomy
Microscopically
Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of micr ...
, veins have a thick outer layer made of
connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
, called the
tunica externa
The tunica externa (New Latin "outer coat"), also known as the tunica adventitia (New Latin "additional coat"), is the outermost tunica (layer) of a blood vessel, surrounding the tunica media. It is mainly composed of collagen and, in arteries, i ...
or ''tunica adventitia''. During procedures requiring venous access such as
venipuncture
In medicine, venipuncture or venepuncture is the process of obtaining intravenous access for the purpose of venous blood sampling (also called ''phlebotomy'') or intravenous therapy. In healthcare, this procedure is performed by medical labor ...
, one may notice a subtle "pop" as the needle penetrates this layer. The middle layer of bands of
smooth muscle are called
tunica media
The tunica media (New Latin "middle coat"), or media for short, is the middle tunica (layer) of an artery or vein. It lies between the tunica intima on the inside and the tunica externa on the outside.
Artery
Tunica media is made up of smooth ...
and are, in general, much thinner than those of arteries, as veins do not function primarily in a contractile manner and are not subject to the high pressures of
systole
Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. The term originates, via New Latin, from Ancient Greek (''sustolē''), from (''sustéllein'' 'to contract'; from ''sun ...
, as arteries are. The interior is lined with
endothelial cells
The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...
called
tunica intima
The tunica intima (New Latin "inner coat"), or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina. The endothelial cells are i ...
. The precise location of veins varies much more from person to person than that of
arteries
An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
.
Function
Veins serve to return blood from organs to the heart. Veins are also called "capacitance vessels" because most of the blood volume (60%) is contained within veins. In
systemic circulation oxygenated blood is pumped by the
left ventricle
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
through the
arteries
An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
to the muscles and organs of the body, where its nutrients and gases are exchanged at
capillaries
A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: ...
. After taking up cellular waste and
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
in capillaries, blood is channeled through vessels that converge with one another to form venules, which continue to converge and form the larger veins. The de-
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
ated blood is taken by veins to the right atrium of the heart, which transfers the blood to the
right ventricle
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
, where it is then pumped through the pulmonary arteries to the
lung
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
s. In
pulmonary circulation
The pulmonary circulation is a division of the circulatory system in all vertebrates. The circuit begins with deoxygenated blood returned from the body to the right atrium of the heart where it is pumped out from the right ventricle to the lungs ...
the
pulmonary vein
The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four ''main pulmonary veins'', two from each lung that drain into the left atrium of the heart. The pulmonary vei ...
s return oxygenated blood from the lungs to the left atrium, which empties into the left ventricle, completing the cycle of blood circulation.
The return of blood to the heart is assisted by the action of the
muscle pump, and by the thoracic pump action of breathing during respiration. Standing or sitting for a prolonged period of time can cause low venous return from venous pooling (vascular) shock.
Fainting
Syncope, commonly known as fainting, or passing out, is a loss of consciousness and muscle strength characterized by a fast onset, short duration, and spontaneous recovery. It is caused by a decrease in blood flow to the brain, typically from ...
can occur but usually baroreceptors within the aortic sinuses initiate a
baroreflex such that angiotensin II and norepinephrine stimulate vasoconstriction and heart rate increases to return blood flow.
Neurogenic
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...
and
hypovolaemic shock
Hypovolemia, also known as volume depletion or volume contraction, is a state of abnormally low extracellular fluid in the body. This may be due to either a loss of both salt and water or a decrease in blood volume. Hypovolemia refers to the loss ...
can also cause fainting. In these cases, the smooth muscles surrounding the veins become slack and the veins fill with the majority of the blood in the body, keeping blood away from the brain and causing unconsciousness. Jet pilots wear pressurized suits to help maintain their venous return and blood pressure.
The arteries are perceived as carrying oxygenated blood to the tissues, while veins carry deoxygenated blood back to the heart. This is true of the systemic circulation, by far the larger of the two circuits of blood in the body, which transports oxygen from the heart to the tissues of the body. However, in pulmonary circulation, the arteries carry deoxygenated blood from the heart to the lungs, and veins return blood from the lungs to the heart. The difference between veins and arteries is their direction of flow (out of the heart by arteries, returning to the heart for veins), not their oxygen content. In addition, deoxygenated blood that is carried from the tissues back to the heart for reoxygenation in the systemic circulation still carries some oxygen, though it is considerably less than that carried by the systemic arteries or pulmonary veins.
Although most veins take blood back to the heart, there is an exception. Portal veins carry blood between capillary beds. Capillary beds are a network of blood vessels that link the venules to the arterioles and allow for the exchange of materials across the membrane from the blood to tissues, and vice versa. For example, the hepatic portal vein takes blood from the capillary beds in the digestive tract and transports it to the capillary beds in the liver. The blood is then drained in the gastrointestinal tract and spleen, where it is taken up by the hepatic veins, and blood is taken back into the heart. Since this is an important function in mammals, damage to the hepatic portal vein can be dangerous. Blood clotting in the hepatic portal vein can cause portal hypertension, which results in a decrease of blood fluid to the liver.
Cardiac veins
In the
coronary circulation the veins that remove the deoxygenated blood from the
heart muscle
Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle tha ...
are known as cardiac veins or coronary veins. These include the
great cardiac vein
The great cardiac vein (left coronary vein) begins at the apex of the heart and ascends along the anterior longitudinal sulcus to the base of the ventricles.
It then curves around the left margin of the heart to reach the posterior surface. It m ...
, the
middle cardiac vein
The middle cardiac vein commences at the apex of the heart; ascends in the posterior longitudinal sulcus, and ends in the coronary sinus
In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that c ...
, the
small cardiac vein The small cardiac vein, also known as the right coronary vein, is a coronary vein that drains the right atrium and right ventricle of the heart. Despite its size, it is one of the major drainage vessels for the heart.
Location
The small cardiac ...
, the
smallest cardiac veins, and the
anterior cardiac veins
The anterior cardiac veins (or anterior veins of right ventricle) comprise a variable number of small vessels, usually between two and five, which collect blood from the front of the right ventricle and open into the right atrium; the right margin ...
. Cardiac veins carry blood with a poor level of oxygen, from the heart muscle to the
right atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
. Most of the blood of the cardiac veins returns through the
coronary sinus
In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena ...
. The anatomy of the veins of the heart is very variable, but generally it is formed by the following veins: heart veins that go into the coronary sinus: the great cardiac vein, the middle cardiac vein, the small cardiac vein, the posterior vein of the
left ventricle
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
, and the vein of Marshall. Heart veins that go directly to the right atrium: the anterior cardiac veins, and the smallest cardiac veins (Thebesian veins).
Clinical significance
Diseases
Venous insufficiency
Venous insufficiency is the most common disorder of the venous system, and is usually manifested as
spider veins
Telangiectasias, also known as spider veins, are small dilated blood vessels that can occur near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter. These dilated blood vessels can develop anywhere on ...
or
varicose veins
Varicose veins, also known as varicoses, are a medical condition in which superficial veins become enlarged and twisted. These veins typically develop in the legs, just under the skin. Varicose veins usually cause few symptoms. However, some indiv ...
. Several treatments are available including
endovenous thermal ablation
Varicose veins, also known as varicoses, are a medical condition in which superficial veins become enlarged and twisted. These veins typically develop in the legs, just under the skin. Varicose veins usually cause few symptoms. However, some indi ...
(using radiofrequency or laser energy),
vein stripping
Vein stripping is a surgical procedure done under general or local anaesthetic to aid in the treatment of varicose veins and other manifestations of chronic venous disease. The vein "stripped" (pulled out from under the skin using minimal incisio ...
,
ambulatory phlebectomy
Ambulatory phlebectomy is a minisurgical treatment for superficial varicose veins and so-called side branches.
History
This technique has been attributed to Dr Robert Muller a Swiss dermatologist who started experimenting with this technique i ...
, foam
sclerotherapy
Sclerotherapy (the word reflects the Greek ''skleros'', meaning ''hard'')
is a procedure used to treat blood vessel malformations (vascular malformations) and also malformations of the lymphatic system. A medicine is injected into the vessels, wh ...
,
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
, or compression.
Postphlebitic syndrome
Post-thrombotic syndrome (PTS), also called postphlebitic syndrome and venous stress disorder is a medical condition that may occur as a long-term complication of deep vein thrombosis (DVT).
Signs and symptoms
Signs and symptoms of PTS in the leg ...
is venous insufficiency that develops following
deep vein thrombosis
Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...
.
Deep vein thrombosis
Deep vein thrombosis is a condition in which a
blood clot
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 ...
forms in a deep vein. This is usually the veins of the legs, although it can also occur in the veins of the arms. Immobility, active cancer, obesity, traumatic damage and congenital disorders that make clots more likely are all risk factors for deep vein thrombosis. It can cause the affected limb to swell, and cause pain and an overlying skin rash. In the worst case, a deep vein thrombosis can extend, or a part of a clot can break off and land in the lungs, called
pulmonary embolism
Pulmonary embolism (PE) is a blockage of an pulmonary artery, artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include dyspnea, shortness of breath, chest pain p ...
.
The decision to treat deep vein thrombosis depends on its size, a person's symptoms, and their risk factors. It generally involves
anticoagulation
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where the ...
to prevents clots or to reduce the size of the clot.
Portal hypertension
The portal veins are found within the abdomen and carry blood through to the liver.
Portal hypertension is associated with cirrhosis or disease of the liver, or other conditions such as an obstructing clot (
Budd Chiari syndrome) or compression from tumours or tuberculosis lesions. When the pressure increases in the portal veins, a collateral circulation develops, causing visible veins such as
oesophageal varices
Esophageal varices are extremely dilated sub-mucosal veins in the lower third of the esophagus. They are most often a consequence of portal hypertension, commonly due to cirrhosis. People with esophageal varices have a strong tendency to develop s ...
.
Other
Thrombophlebitis
Thrombophlebitis is a phlebitis (inflammation of a vein) related to a thrombus (blood clot). When it occurs repeatedly in different locations, it is known as thrombophlebitis migrans ( migratory thrombophlebitis).
Signs and symptoms
The following ...
is an inflammatory condition of the veins related to
blood clots
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 cr ...
.
Imaging
![Venous valve 00013](https://upload.wikimedia.org/wikipedia/commons/5/54/Venous_valve_00013.gif)
Ultrasound
Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hea ...
, particularly
duplex ultrasound
Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids (usually blood), and their relative velocity to the probe. By calculating the frequency shift of a ...
, is a common way that veins can be seen.
Veins of clinical significance
The
Batson venous plexus
The Batson venous plexus (Batson veins) is a network of valveless veins in the human body that connect the deep pelvic veins and thoracic veins (draining the inferior end of the urinary bladder, breast and prostate) to the internal vertebral ve ...
, or simply Batson's plexus, runs through the inner vertebral column connecting the thoracic and pelvic veins. These veins are noted for being valveless, which is believed to be the reason for
metastasis
Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...
of certain cancers.
The
great saphenous vein
The great saphenous vein (GSV, alternately "long saphenous vein"; ) is a large, subcutaneous, superficial vein of the leg. It is the longest vein in the body, running along the length of the lower limb, returning blood from the foot, leg and thi ...
is the most important superficial vein of the lower limb. First described by the
Persia
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
n physician
Avicenna, this vein derives its name from the word ''safina'', meaning "hidden". This vein is "hidden" in its own
fascial compartment
A fascial compartment is a section within the body that contains muscles and nerves and is surrounded by deep fascia. In the human body, the limbs can each be divided into two segments – the upper limb can be divided into the arm and the forea ...
in the thigh and exits the fascia only near the knee. Incompetence of this vein is an important cause of
varicose veins
Varicose veins, also known as varicoses, are a medical condition in which superficial veins become enlarged and twisted. These veins typically develop in the legs, just under the skin. Varicose veins usually cause few symptoms. However, some indiv ...
of lower limbs.
The
Thebesian veins within the heart muscle are valveless veins that drain directly into the chambers of the heart. The coronary veins all empty into the
coronary sinus
In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena ...
which empties into the right atrium.
The
dural venous sinuses
The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous channels found between the endosteal and meningeal layers of dura mater in the brain. They receive blood from the cerebral veins, receive cere ...
within the dura mater surrounding the brain receive blood from the brain and also are a point of entry of cerebrospinal fluid from
arachnoid villi
Arachnoid granulations (also arachnoid villi, and pacchionian granulations or bodies) are small protrusions of the arachnoid mater (the thin second layer covering the brain) into the outer membrane of the dura mater (the thick outer layer). They ...
absorption. Blood eventually enters the internal jugular vein.
Phlebology
![Venous valve](https://upload.wikimedia.org/wikipedia/commons/4/4a/Venous_valve.svg)
''Phlebology'' is a multidisciplinary specialty of medicine that deals with the diagnosis and treatment of venous and lymphatic disorders and related conditions such as vascular anomalies in both adult and paediatric patients. Phlebology derives from the two core disciplines of medicine and surgery and incorporates relevant aspects of vascular and endovascular surgery, interventional radiology, dermatology, vascular medicine and haematology. A medical specialist in phlebology is termed a
phlebologist
A phlebologist is a medical specialist in the diagnosis and treatment of disorders of venous origin. The specialty of phlebology has developed to enable physicians sharing an interest in venous disease and health to share knowledge and experience ...
. A related image is called a
phlebograph.
The Union Internationale de Phlébologie (UIP) is committed to the global expansion of knowledge in the growing field of phlebology and aims to facilitate the advancement of science by encouraging research and education in all aspects of venous and lymphatic disease. The Union is ultimately aiming to facilitate comprehensive training programs in its member countries with the ultimate aim of establishing phlebology as a recognised multidisciplinary specialty of medicine.
The Australasian College of Phlebology (ACP) founded in 1993 has established a comprehensive four year training program in phlebology incorporating an online modular curriculum that complements supervised clinical training.
The
American Medical Association
The American Medical Association (AMA) is a professional association and lobbying group of physicians and medical students. Founded in 1847, it is headquartered in Chicago, Illinois. Membership was approximately 240,000 in 2016.
The AMA's sta ...
added phlebology to their list of self-designated practice specialties in 2005. In 2007 the American Board of Phlebology (ABPh), subsequently known as the American Board of Venous & Lymphatic Medicine (ABVLM), was established to improve the standards of phlebologists and the quality of their patient care by establishing a certification examination, as well as requiring maintenance of certification. Although not a Member Board of the American Board of Medical Specialties (ABMS), the American Board of Venous & Lymphatic Medicine uses a certification exam based on ABMS standards.
The
American Vein and Lymphatic Society
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
(AVLS), formerly the American College of Phlebology (ACP) one of the largest medical societies in the world for physicians and allied health professionals working in the field of phlebology, has 2000 members. The AVLS encourages education and training to improve the standards of medical practitioners and the quality of patient care.
The
American Venous Forum (AVF)
The American Venous Forum (AVF) is the major national academic society focused on venous and lymphatic disease in the United States. Its mission includes education, research, and advocacy. The AVF is the sponsor organization for the ''Journal of ...
is a medical society for physicians and allied health professionals dedicated to improving the care of patients with venous and lymphatic disease. The majority of its members manage the entire spectrum of venous and lymphatic diseases – from varicose veins to congenital abnormalities to deep vein thrombosis to chronic venous diseases. Founded in 1987, the AVF encourages research, clinical innovation, hands-on education, data collection and patient outreach.
History
![Charta ex qva figvram parare convenit, illi qvae nervorvm seriem exprimit appendendam, 1543](https://upload.wikimedia.org/wikipedia/commons/b/b1/Charta_ex_qva_figvram_parare_convenit%2C_illi_qvae_nervorvm_seriem_exprimit_appendendam%2C_1543..JPG)
The earliest known writings on the circulatory system are found in the
Ebers Papyrus (16th century BCE), an
ancient Egyptian medical papyrus containing over 700 prescriptions and remedies, both physical and spiritual. In the
papyrus
Papyrus ( ) is a material similar to thick paper that was used in ancient times as a writing surface. It was made from the pith of the papyrus plant, '' Cyperus papyrus'', a wetland sedge. ''Papyrus'' (plural: ''papyri'') can also refer to a ...
, it acknowledges the connection of the heart to the arteries. The Egyptians thought air came in through the mouth and into the lungs and heart. From the heart, the air travelled to every member through the arteries. Although this concept of the circulatory system is only partially correct, it represents one of the earliest accounts of scientific thought.
In the 6th century BCE, the knowledge of circulation of vital fluids through the body was known to the
Ayurvedic physician
Sushruta in
ancient India
According to consensus in modern genetics, anatomically modern humans first arrived on the Indian subcontinent from Africa between 73,000 and 55,000 years ago. Quote: "Y-Chromosome and Mt-DNA data support the colonization of South Asia by m ...
.
[ He also seems to have possessed knowledge of the ]arteries
An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...
, described as 'channels' by Dwivedi & Dwivedi (2007).[Dwivedi, Girish & Dwivedi, Shridhar (2007)]
"History of Medicine: Sushruta – the Clinician – Teacher par Excellence"
, ''Indian J Chest Dis Allied Sci'' Vol.49 pp.243-4, National Informatics Centre (Government of India). The valves of the heart
A heart valve is a Check valve, one-way valve that allows blood flow, blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow thro ...
were discovered by a physician of the Hippocratean school around the 4th century BCE. However their function was not properly understood then. Because blood pools in the veins after death, arteries look empty. Ancient anatomists assumed they were filled with air and that they were for transport of air.
The Greek physician Herophilus
Herophilos (; grc-gre, Ἡρόφιλος; 335–280 BC), sometimes Latinised Herophilus, was a Greek physician regarded as one of the earliest anatomists. Born in Chalcedon, he spent the majority of his life in Alexandria. He was the first ...
distinguished veins from arteries but thought that the pulse
In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the n ...
was a property of arteries themselves. Greek anatomist Erasistratus
Erasistratus (; grc-gre, Ἐρασίστρατος; c. 304 – c. 250 BC) was a Greek anatomist and royal physician under Seleucus I Nicator of Syria. Along with fellow physician Herophilus, he founded a school of anatomy in Alexandria, where th ...
observed that arteries that were cut during life bleed. He ascribed the fact to the phenomenon that air escaping from an artery is replaced with blood that entered by very small vessels between veins and arteries. Thus he apparently postulated capillaries but with reversed flow of blood.
In 2nd century AD Rome
, established_title = Founded
, established_date = 753 BC
, founder = King Romulus (legendary)
, image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg
, map_caption ...
, the Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
physician Galen
Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be one of ...
knew that blood vessels carried blood and identified venous (dark red) and arterial (brighter and thinner) blood, each with distinct and separate functions. Growth and energy were derived from venous blood created in the liver from chyle, while arterial blood gave vitality by containing pneuma (air) and originated in the heart. Blood flowed from both creating organs to all parts of the body where it was consumed and there was no return of blood to the heart or liver. The heart did not pump blood around, the heart's motion sucked blood in during diastole and the blood moved by the pulsation of the arteries themselves.
Galen believed that the arterial blood was created by venous blood passing from the left ventricle to the right by passing through 'pores' in the interventricular septum, air passed from the lungs via the pulmonary artery to the left side of the heart. As the arterial blood was created 'sooty' vapors were created and passed to the lungs also via the pulmonary artery to be exhaled.
In 1025, ''The Canon of Medicine
''The Canon of Medicine'' ( ar, القانون في الطب, italic=yes ''al-Qānūn fī al-Ṭibb''; fa, قانون در طب, italic=yes, ''Qanun-e dâr Tâb'') is an encyclopedia of medicine in five books compiled by Persian physician-phi ...
'' by the Persian physician Avicenna "erroneously accepted the Greek notion regarding the existence of a hole in the ventricular septum by which the blood traveled between the ventricles." While also refining Galen's erroneous theory of the pulse, Avicenna provided the first correct explanation of pulsation: "Every beat of the pulse comprises two movements and two pauses. Thus, expansion : pause : contraction : pause. ..The pulse is a movement in the heart and arteries ... which takes the form of alternate expansion and contraction."
In 1242, the Arabian physician Ibn al-Nafis became the first person to accurately describe the process of pulmonary circulation
The pulmonary circulation is a division of the circulatory system in all vertebrates. The circuit begins with deoxygenated blood returned from the body to the right atrium of the heart where it is pumped out from the right ventricle to the lungs ...
, for which he has been described as the ''Arab Father of Circulation''. Ibn al-Nafis stated in his ''Commentary on Anatomy in Avicenna's Canon'':
"...the blood from the right chamber of the heart must arrive at the left chamber but there is no direct pathway between them. The thick septum of the heart is not perforated and does not have visible pores as some people thought or invisible pores as Galen thought. The blood from the right chamber must flow through the vena arteriosa (pulmonary artery
A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and ...
) to the lungs, spread through its substances, be mingled there with air, pass through the arteria venosa (pulmonary vein
The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four ''main pulmonary veins'', two from each lung that drain into the left atrium of the heart. The pulmonary vei ...
) to reach the left chamber of the heart and there form the vital spirit..."
In addition, Ibn al-Nafis had an insight into what would become a larger theory of the capillary
A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: ...
circulation. He stated that "there must be small communications or pores (''manafidh'' in Arabic) between the pulmonary artery and vein," a prediction that preceded the discovery of the capillary system by more than 400 years. Ibn al-Nafis' theory, however, was confined to blood transit in the lungs and did not extend to the entire body.
Michael Servetus
Michael Servetus (; es, Miguel Serveto as real name; french: Michel Servet; also known as ''Miguel Servet'', ''Miguel de Villanueva'', ''Revés'', or ''Michel de Villeneuve''; 29 September 1509 or 1511 – 27 October 1553) was a Spanish th ...
was the first European to describe the function of pulmonary circulation, although his achievement was not widely recognized at the time, for a few reasons. He firstly described it in the "Manuscript of Paris" (near 1546), but this work was never published. And later he published this description, but in a theological treatise, ''Christianismi Restitutio'', not in a book on medicine. Only three copies of the book survived but these remained hidden for decades, the rest were burned shortly after its publication in 1553 because of persecution of Servetus by religious authorities.
Better known discovery of pulmonary circulation was by Vesalius
Andreas Vesalius (Latinized from Andries van Wezel) () was a 16th-century anatomist, physician, and author of one of the most influential books on human anatomy, ''De Humani Corporis Fabrica Libri Septem'' (''On the fabric of the human body'' '' ...
's successor at Padua
Padua ( ; it, Padova ; vec, Pàdova) is a city and ''comune'' in Veneto, northern Italy. Padua is on the river Bacchiglione, west of Venice. It is the capital of the province of Padua. It is also the economic and communications hub of the ...
, Realdo Colombo
Matteo Realdo Colombo (c. 1515 – 1559) was an Italian professor of anatomy and a surgeon at the University of Padua between 1544 and 1559.
Early life and education
Matteo Realdo Colombo or Realdus Columbus, was born in Cremona, Lombardy, th ...
, in 1559.
Finally, William Harvey
William Harvey (1 April 1578 – 3 June 1657) was an English physician who made influential contributions in anatomy and physiology. He was the first known physician to describe completely, and in detail, the systemic circulation and propert ...
, a pupil of Hieronymus Fabricius
Girolamo Fabrici d'Acquapendente, also known as Girolamo Fabrizio or Hieronymus Fabricius (20 May 1533 – 21 May 1619), was a pioneering anatomist and surgeon known in medical science as "The Father of Embryology."
Life and accomplishments ...
(who had earlier described the valves of the veins without recognizing their function), performed a sequence of experiments, and published ''Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus'' in 1628, which "demonstrated that there had to be a direct connection between the venous and arterial systems throughout the body, and not just the lungs. Most importantly, he argued that the beat of the heart produced a continuous circulation of blood through minute connections at the extremities of the body. This is a conceptual leap that was quite different from Ibn al-Nafis' refinement of the anatomy and bloodflow in the heart and lungs." This work, with its essentially correct exposition, slowly convinced the medical world. However, Harvey was not able to identify the capillary system connecting arteries and veins; these were later discovered by Marcello Malpighi
Marcello Malpighi (10 March 1628 – 30 November 1694) was an Italian biologist and physician, who is referred to as the "Founder of microscopical anatomy, histology & Father of physiology and embryology". Malpighi's name is borne by several ph ...
in 1661.
In 1956, André Frédéric Cournand
André Frédéric Cournand (September 24, 1895 – February 19, 1988) was a French-American physician and physiologist.
Biography
Cournand was awarded the Nobel Prize in Physiology or Medicine in 1956 along with Werner Forssmann and Dickinson W ...
, Werner Forssmann
Werner Theodor Otto Forßmann (Forssmann in English; ; 29 August 1904 – 1 June 1979) was a German researcher and physician from Germany who shared the 1956 Nobel Prize in Medicine (with Andre Frederic Cournand and Dickinson W. Richards) for ...
and Dickinson W. Richards were awarded the Nobel Prize
The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...
in Medicine "for their discoveries concerning heart catheterization
Cardiac catheterization (heart cath) is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.
A common example of cardiac catheterization is coronary catheterization tha ...
and pathological changes in the circulatory system."
In his Nobel lecture, Forssmann credits Harvey as birthing cardiology with the publication of his book in 1628.
In the 1970s, Diana McSherry developed computer-based systems to create images of the circulatory system and heart without the need for surgery.
See also
* May–Thurner syndrome
May–Thurner syndrome (MTS), also known as the iliac vein compression syndrome, is a condition in which compression of the common venous outflow tract of the left lower extremity may cause discomfort, swelling, pain or clots (deep venous thrombo ...
* Nutcracker syndrome
The nutcracker syndrome (NCS) results most commonly from the compression of the left renal vein (LRV) between the abdominal aorta (AA) and superior mesenteric artery (SMA), although other variants exist. The name derives from the fact that, in the ...
* Thoracic outlet syndrome
* Phlebologist
A phlebologist is a medical specialist in the diagnosis and treatment of disorders of venous origin. The specialty of phlebology has developed to enable physicians sharing an interest in venous disease and health to share knowledge and experience ...
* Vascular surgery
* Cardiovascular disease
* Cardiology
Cardiology () is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart d ...
References
Further reading
*
External links
Merck Manual article on veins
* A on the veins' and lymphatic systems of the upper limb
{{Use dmy dates, date=April 2017
Veins
Cardiovascular physiology