innominate vein

n. See brachiocephalic vein.

vein

(van) [L. vena, vein]

SYSTEMIC VEINS

SYSTEMIC VEINSA vessel carrying blood toward the heart. Most veins originate in capillaries and drain into increasingly larger veins until their blood is delivered to the right atrium of the heart. Portal veins also originate in capillaries, but their branches decrease in size to pass through another set of capillaries before joining more typical veins on their way toward the heart. For all veins, the precursor veins that empty into a secondary vein are called tributaries of the secondary vein. See: illustration; circulation; vena

The deep veins typically accompany arteries, and artery and vein have the same name, e.g., radial artery and radial vein. In contrast, the superficial or subcutaneous veins typically travel alone. The deep and superficial veins have frequent interconnections, i.e., anastomoses; in general, veins have more anastomoses than do arteries. Throughout the body, the pattern of veins is more variable than is the pattern of arteries.

The walls of most veins have three layers: an endothelial lining, which folds at intervals into leaflets that act as one-way valves, a thin middle layer often containing smooth muscle, and a thin outer layer composed of fibrous connective tissue. In contrast, the veins of the brain have no valves, and the largest venous channels in the brain are not veins but rather endothelial-lined spaces in the dura mater called 'dural sinuses' or 'venous sinuses'; dural sinuses receive blood from cerebral veins and deliver blood to other dural sinuses or to the internal jugular vein.

accessory hemiazygos vein

A vein running along the back wall of the upper thorax to the left of the thoracic aorta; at the level of the seventh thoracic vertebra, the accessory hemiazygos vein bends rightward, runs behind the aorta, and drains into the azygos vein. Tributaries of the accessory hemiazygos vein include the left superior intercostal veins, the upper left intercostal veins, and left bronchial veins. The patterns and interconnections of the azygos, hemiazygos, and accessory azygos veins are variable.

adrenal vein

The adrenal glands are supplied by three or more arteries on each side, but they are drained by only one right vein and one left vein. On the right, the adrenal vein empties into the inferior vena cava; on the left, the adrenal vein empties into the left renal vein. Synonym: suprarenal vein

angular vein

Facial vein.

anterior cardiac vein

One of the small veins running up along the surface of the right ventricle of the heart and draining directly into the right atrium.

anterior facial vein

Facial vein.

anterior jugular vein

A neck vein that originates near the hyoid bone and descends vertically over the hyoid and infrahyoid strap muscles; behind the sternal head of the sternocleidomastoid muscle, the vein turns laterally and empties into the external jugular vein (or, sometimes, into the subclavian vein).

anterior tibial vein

A vein that drains blood from the lower leg and foot and that merges with the posterior tibial vein to form the popliteal vein in the popliteal fossa. See: illustration for illus.

ascending lumbar vein

An anterior-posterior vein along the posterior abdominal wall that connects the common iliac, iliolumbar, and lumbar veins; it empties into the subcostal, azygos, hemiazygos, or first lumbar vein.

axillary vein

The continuation of the basilic vein in the upper arm; it accompanies the axillary artery and becomes the subclavian vein at the lateral border of the first rib. Tributaries of the axillary vein include the brachial, the cephalic, and the subscapular veins. See: illustration for illlus.

azygos vein

A vein running along the back wall of the thorax on the right side of the thoracic aorta; at the level of the fourth thoracic vertebra, the azygos vein curves forward, over the top of the hilum (root) of the right lung, and empties its blood into the superior vena cava. The azygos vein receives blood from the back wall of the trunk via the hemiazygos, accessory azygos, right superior intercostal, right intercostal, mediastinal, pericardial, right subcostal, and right ascending lumbar veins. The patterns and interconnections of the azygos, hemiazygos, and accessory azygos veins are variable.

basal vein

A vein along the base of the brain that runs from the cavernous sinus, around the cerebral peduncle, and into the vein of Galen. Tributaries of the basal vein include the anterior cerebral, deep middle cerebral, and striate veins.

basilic vein

A superficial vein running along the lateral side of the upper limb. It begins in the dorsal veins of the hand, continues along the dorsal (posterior) medial side of the anterior forearm where it angles medially, and then passes over ventral (anterior) medial side of the elbow; in the antecubital fossa, it is joined by the median cubital vein, a branch of the cephalic vein. Approx. one third of the way up the medial surface of the arm, the basilic vein dives, alongside the medial edge of the biceps brachii muscle, to run alongside the brachial artery; when the brachial artery becomes the axillary artery, the basilic vein becomes the axillary vein. It is usually chosen for intravenous injection or withdrawal of blood.

brachial veins

Either of a pair of veins that accompany the brachial artery into the upper arm (as venae comitantes) and then empty into the axillary vein.

brachiocephalic vein

The brachiocephalic vein is formed by the merger of the subclavian and internal jugular veins in the root of the neck. The right brachiocephalic vein is about 2.5 cm long and the left is about 6 cm long. The right and the left brachiocephalic veins join, behind the junction of the right border of the sternum and the right first costal cartilage, to form the superior vena cava. Tributaries of both brachiocephalic veins include the vertebral, internal mammary, and inferior thyroid veins; the left brachiocephalic vein also receives the left superior intercostal, thymic, and pericardial veins. See: illustration for illus.

bronchial vein

Two right and two left bronchial veins collect systemic (deoxygenated) blood from the bronchi and other lung tissues and return it to the systemic venous pool via the azygos vein on the right and the accessory hemiazygos vein on the left.

cardiac vein

Any of the veins that run along the surface of the heart parallel to the coronary arteries, drain the heart muscle, and empty into the coronary sinus or the right atrium. See: coronary artery for illus.

cardinal vein

Along with the umbilical and the vitelline veins, the cardinal veins form one of the three venous systems of the early embryo. The cardinal veins return blood to the heart from the body of the embryo, and they are the precursors of the major thoracic veins, including the subclavian, brachiocephalic, azygos, internal jugular veins, and the superior vena cava.

central vein

The vein that accompanies the central artery inside the optic nerve.

cephalic vein

A superficial vein of the upper limb, it forms over the "anatomical snuff box", behind the base of the thumb, and runs medially onto the anterior (ventral) surface of the forearm. It runs up the lateral side of the anterior (ventral) surface of the forearm, it crosses in front of the elbow, and continues up the arm along the biceps brachii and deltoid muscles. Below the clavicle, the cephalic vein dives into the intraclavicular fossa to empty into the axillary vein. In the antecubital fossa, a large branch, the median cubital vein, runs laterally and joins the basilic vein.

cerebellar vein

The superior or the inferior cerebellar vein, both of which run along the surface of the cerebellum; both veins drain blood from the cerebellum, emptying the blood into nearby dural sinuses.

cerebral vein

Any of the veins draining the brain. Cerebral veins differ from veins outside the skull in that (1) cerebral veins do not run with cerebral arteries; (2) cerebral veins do not have valves; and (3) walls of cerebral veins contain no muscle.

The venous circulation of the brain begins with venules that run from inside the brain to the surface where they bend 90° and run along the surface inside the pia mater. Anastomosing venous plexuses collect in the pia to form the cerebral veins, which eventually cross the subarachnoid space and empty into dural sinuses. The dural sinuses interconnect and eventually empty into the internal jugular veins.

See: dural sinus

choroidal vein

The vein that follows and drains the choroid plexuses in the cerebral ventricles. Outside the ventricles, it merges with the thalamostriate vein to form the internal cerebral vein.

circumflex iliac vein

The vein accompanying the circumflex iliac artery; it empties into the external iliac vein. Synonym: deep circumflex iliac vein

common iliac vein

The vein accompanying the common iliac artery; it is formed by the union of the external and internal iliac veins, and it ends by merging with the opposite common iliac vein to form the inferior vena cava. The right iliac vein is shorter than the left. Tributaries of the common iliac vein include the iliolumbar, lateral sacral, and median sacral veins.

cranial venous sinus vein

Any of a group of veins between the two layers of the dura mater that drain blood and reabsorbed cerebrospinal fluid from the brain and join the internal jugular vein.

cubital vein

Median cubital vein.

deep circumflex iliac vein

Circumflex iliac vein.

diploic vein

Any of the valveless, thin-walled veins that drain the bones of the skull.

dorsal vein of the penis

The superficial or the deep dorsal vein of the penis, each of which is an unpaired (single) midline vein. The superficial dorsal vein empties into the external pudendal vein; the deep dorsal vein drains the erectile tissues and empties into the internal pudendal vein.

emissary vein

Any of the small veins that run through foramina and other apertures in the skull. Emissary veins are valveless and allow the spread of microbes between the outside and inside of the skull. The emissary veins vary from person to person.

epigastric vein

The superior or the inferior epigastric vein.

external iliac vein

The continuation of the femoral vein proximal to the inguinal ligament; it accompanies the external iliac artery, and it joins the internal iliac vein to form the common iliac vein. Tributaries of the external iliac vein include the inferior epigastric, deep circumflex iliac, and pubic veins.

external jugular vein

A vein that drains blood from the scalp and face; it arises from the merger of the posterior facial and posterior auricular veins behind the angle of the mandible. The external jugular vein runs superficially down the neck, crossing the sternocleidomastoid muscle, to drain into the subclavian vein. Tributaries of the external jugular vein include the posterior external jugular, transverse cervical, suprascapular, and anterior jugular veins. See: illustrationand for illus.

facial vein

The facial vein runs at an angle, on each side of the face, from the bridge of the nose to halfway along the line of the jaw. The first tributaries of the facial vein include the supratrochlear, supraorbital, and superior ophthalmic veins (which drain the forehead and orbit); other tributaries include the nasal, deep facial, inferior palpebral, superior and inferior labial, buccinator, parotid, and masseteric veins. Below the jaw and before emptying into the internal jugular vein (at the level of the hyoid bone in the neck), the facial vein receives blood from the submental, tonsillar, external palatine, and submandibular veins. There are no valves in the facial vein, and blood can move backwards into its tributaries, such as the deep facial vein; the deep facial vein is interconnected with the cavernous sinus inside the skull, and microbes from facial infections can use this route to reach intracranial veins. Synonym: angular vein; anterior facial vein

femoral vein

The vein that accompanies the femoral artery. The femoral vein is the continuation of the popliteal vein as it enters the adductor canal of the thigh. As it passes the inguinal ligament, the femoral vein becomes the external iliac vein. Tributaries of the femoral vein include the deep femoral (profunda femoris), the saphenous, and the lateral and medial circumflex femoral veins.

vein of Galen

See: Galen, Claudius

gastric vein

The left gastric, the right gastric, or a short gastric vein. The left gastric vein drains much of the stomach and empties into the portal vein; tributaries of the left gastric vein include the esophageal veins. The right gastric vein is small, it drains the pyloric region of the stomach, and it empties into the portal vein. The 4-5 short gastric veins drain part of the greater curvature of the stomach and empty into the splenic vein.

gastroepiploic vein

The right and the left gastroepiploic veins accompany the gastroepiploic arteries; the right gastroepiploic vein drains into the splenic vein, while the left gastroepiploic vein drains into the superior mesenteric vein.

great cardiac vein

A large vein on the anterior surface of the heart; it runs in the anterior interventricular groove alongside the left anterior descending artery. It drains the same area of the heart that is supplied by the artery, and it also receives blood from the left marginal vein. The great cardiac vein follows the coronary sulcus to the left to empty into the coronary sinus on the posterior surface of the heart.

great cerebral vein

Vein of Galen.

great saphenous vein

Long saphenous vein.

greater saphenous vein

Long saphenous vein.

hemiazygos vein

A vein running along the back wall of the lower thorax on the left side of the thoracic aorta. At the level of the eighth thoracic vertebra, the hemiazygos vein bends to the right, runs behind the aorta, and empties into the azygos vein. Tributaries to the hemiazygos vein include the left bronchial, left lower intercostal, left subcostal, and left ascending lumbar veins; often, there is a caudal anastomosis with the left renal vein. The patterns and interconnections of the azygos, hemiazygos, and accessory azygos veins are variable.

hemorrhoidal vein

Rectal vein.

hepatic vein

Any of the veins that drain the liver sinusoids into the inferior vena cava on the posterior surface of the liver. Inside the liver, central veins directly drain the sinusoids, the central veins then join into interlobular veins, and the interlobular veins merge to become hepatic veins. All the venous blood that enters the liver from both the portal vein and the hepatic artery leaves the liver through the hepatic veins.

inferior epigastric vein

The vein accompanying the inferior epigastric artery; it empties into the external iliac vein.

inferior mesenteric vein

The vein that accompanies the inferior mesenteric artery; it drains the rectum and the sigmoid and descending colon, and it empties into the splenic vein.

inferior phrenic vein

Any of the veins that accompany the inferior phrenic artery and empty into the inferior vena cava and, on the left, into the adrenal vein.

inferior striated vein

One of the branches of the basal vein that drain the corpus striatum.

inferior thyroid vein

A vein draining the venous plexus of the thyroid gland, the trachea, the larynx, and the local esophagus. The inferior thyroid vein empties into the brachiocephalic vein or the superior vena cava.

innominate vein

Brachiocephalic vein.

intercostal vein

Any of the veins that accompany the intercostal arteries and drain blood from the walls of the chest. The upper intercostal vein empties into the ipsilateral brachiocephalic or vertebral vein. Intercostal veins 2-4 merge to form the superior intercostal vein, which drains into the azygos vein on the right and the accessory hemiazygos vein on the left. Lower intercostal veins drain directly into the azygos vein on the right and the hemiazygos vein on the left. Synonym: posterior intercostal vein

internal cerebral vein

A vein in each cerebral hemisphere formed by the merger of the thalamostriate and choroid veins; it drains the deep regions of the hemisphere.

internal iliac vein

The vein that accompanies the internal iliac artery; it merges with the external iliac vein to form the common iliac vein. Tributaries of the internal iliac vein include the gluteal, internal pudendal, obturator, lateral sacral, anterior sacral, middle rectal, vesical, uterine, and vaginal veins.

internal jugular vein

A large vein in the neck, it drains the skull, brain, and parts of the face and neck. It originates in the jugular foramen at the base of the skull and descends vertically (behind the sternocleidomastoid muscle) in the carotid sheath. At its base, the internal jugular vein merges with the subclavian vein behind the clavicle to form the brachiocephalic vein.

The internal jugular vein is forms in the base of the skull by the merger of the inferior petrosal and sigmoid sinuses. As the vein descends through the neck, tributary veins include the facial, lingual, pharyngeal, superior thyroid, and middle thyroid veins.

The right internal jugular vein is often the blood vessel used for medical access to the central venous circulation and to the right side of the heart.

internal mammary vein

The vein accompanying the internal mammary artery. Synonym: mammary vein

internal thoracic vein

Internal mammary vein.

jugular vein

The internal or the external jugular vein.

Labbé vein

See: Labbé vein

lesser saphenous vein

Short saphenous vein.

lingual vein

The dorsal or the deep lingual vein, both of which empty into the internal jugular vein.

long saphenous vein

The longest vein in the body, the long saphenous is the major superficial vein of the lower leg. It begins in the venous plexus along the medial side of the foot, and it runs up the medial side of the leg and knee, alongside the saphenous nerve. In the thigh, the long saphenous vein continues up the medial surface, accompanying the medial femoral cutaneous nerve. Before reaching the inguinal ligament, the long saphenous vein slips under the deep fascia of the thigh through a tunnel called the saphenous opening; the vein then empties into the underlying femoral vein. Tributaries of the long saphenous vein include the posterior tibial, posteromedial thigh, anterolateral thigh, superficial epigastric, superficial circumflex iliac, and external pudendal veins. Synonym: great saphenous vein; greater saphenous vein

lumbar vein

Any of the four veins on each side of the body that run transversely and drain the posterior abdominal wall; they accompany the lumbar arteries. The lumbar veins, which are interconnected with each other and with the epigastric veins, empty into the inferior vena cava or the azygos vein.

mammary vein

Internal mammary vein.

maxillary vein

A short vein that runs with the first segment of the maxillary artery. It is the merger of veins from the pterygoid venous plexus, and it joins the superior temporal vein, inside the parotid gland, to form the posterior facial vein.

median cubital vein

A large superficial vein running from lateral to medial across the antecubital fossa to connect the cephalic vein with the basilic vein. The median cubital vein is a common site for blood drawing. Synonym: cubital vein

median vein of the forearm

The median vein begins in the palmar venous plexuses and then runs up the forearm along the anterior (ventral) surface to the antecubital fossa where it joins the basilic vein or the median cubital vein.

meningeal vein

Any of the veins that drain the dura mater; most meningeal veins empty into the superior sagittal sinus.

mesenteric vein

The inferior or the superior mesenteric vein.

middle cardiac vein

A large vein that runs in the posterior interventricular groove of the heart; it accompanies the posterior interventricular artery, and both vein and artery drain the same territory. The middle cardiac vein empties into the coronary sinus.

middle thyroid vein

A vein draining the lower part of the thyroid gland, the larynx, and the trachea; it empties into the internal jugular vein.

oblique vein

A slender vein that runs along the outer surface of the left atrium of the heart and that drains into the coronary sinus. Synonym: oblique vein of the left atrium

oblique vein of the left atrium

Oblique vein.

obturator vein

The vein that accompanies the obturator artery; it empties into the internal iliac vein.

occipital vein

The merger of a network of veins along the posterior scalp into a single vein, the occipital vein, which runs down the scalp and under the trapezius muscle. The occipital vein empties into some or all of these veins: the deep cervical, the vertebral, and the posterior auricular veins.

ophthalmic vein

The superior or the inferior ophthalmic vein. The superior ophthalmic vein drains the upper portion of the orbit, while the inferior ophthalmic vein drains the lower portion; both veins empty into the cavernous sinus inside the skull. Both veins are valveless and anastomose with the facial vein thus interconnecting the extracranial and intracranial venous systems.

ovarian vein

In females, any of the veins that accompany the ovarian artery and that drain the ovary and Fallopian tube. Outside the broad ligament, the ovarian veins collect into two veins on each side of the body. These veins accompany the ovarian artery and merge into a single vein; the right ovarian vein then empties into the inferior cava (below the renal vein), while the left ovarian vein empties into the left renal vein.

pancreatic vein

Any of the veins that drain the body and tail of the pancreas; they empty into the splenic vein.

pancreaticoduodenal vein

The superior or the inferior pancreaticoduodenal veins, which accompany the arteries of the same name. Usually, the superior pancreaticoduodenal vein empties into the portal vein, while the inferior pancreaticoduodenal vein empties into the right gastroepiploic vein.

paraumbilical vein

Any of the veins that connect the anterior abdominal wall with the portal vein. The paraumbilical veins begin in the region of the umbilicus, and they run in the ligamentum teres and the median umbilical ligament.

popliteal vein

The vein that accompanies the popliteal artery. It is formed by the merger of the anterior and posterior tibial veins, and it ends by becoming the femoral vein at the distal opening of the adductor canal. The short saphenous vein is a major tributary of the popliteal vein.

portal vein

The vein that brings most of the venous blood draining from the intestines to the liver. The portal vein originates as the merger of the superior mesenteric and splenic veins underneath the neck of the pancreas. It then passes under the duodenum and joins the common bile duct and the hepatic artery as they run inside the right edge of the lesser omentum, over the epiploic foramen, and into the liver via the porta hepatis. Tributaries of the portal vein include the left gastric, right gastric, paraumbilical, and cystic veins.

posterior facial vein

A vein that begins as the merger of the superior temporal and the maxillary veins inside the parotid gland. The posterior facial vein divides into two branches: an anterior branch that empties into the facial vein, and a posterior branch that joins the posterior auricular vein to form the external jugular vein. Synonym: retromandibular vein

posterior intercostal vein

Intercostal vein.

posterior tibial vein

A deep vein in the lower limb that accompanies the posterior tibial artery; the vein drains the region supplied by the artery. The posterior tibial vein merges with the anterior tibial vein to form the popliteal vein in the popliteal fossa behind the knee.

pudendal vein

Any of the veins accompanying the external or the internal pudendal artery; the pudendal veins empty into the internal iliac vein.

pulmonary vein

Any of the four veins (two from each lung) that return newly-oxygenated blood to the left atrium of the heart. Pulmonary veins have no valves.

radial vein

A vein that drains blood from the forearm and the hand and then empties into the brachial vein.

rectal vein

Any of the veins accompanying the inferior, middle, or superior rectal arteries. The rectal veins originate in an interconnected venous plexus that surrounds the rectum and anal canal and that connects with the vesical (bladder) venous plexus in males and the vaginal venous plexus in females. The inferior rectal vein empties into the internal pudendal vein, the middle rectal vein empties into the internal iliac vein, and the superior rectal vein empties into the inferior mesenteric vein. The anastomoses in the rectal venous plexus allow back-pressure in the portal system to be transmitted through the inferior mesenteric and superior rectal veins to the inferior and middle rectal veins and thus into other systemic veins. Synonym: hemorrhoidal vein

renal vein

A large vein that drains blood from the kidney and empties into the inferior vena cava; the renal veins lie on top of (anterior to) the renal arteries. To reach the vena cava, the left renal vein passes over the aorta and is three times as long as the right renal vein. Tributaries of the left renal vein include the left testicular or ovarian vein and the left adrenal vein.

retromandibular vein

Posterior facial vein.

veins of Retzius

See: Retzius, Anders Adolf

rolling vein

A vein that moves to the side during blood collection, generally because it is not anchored properly during the procedure.

sacralvein

Any of the veins accompanying the lateral or middle sacral arteries; the sacral veins empty into the internal iliac vein.

saphenous vein

The long or the short saphenous vein.

short saphenous vein

A superficial leg vein that begins in the venous plexus that drains the lateral side of the foot. The short saphenous vein ascends the lateral side of the posterior leg (the calf). Nearing the knee, the vein runs in the midline between the heads of the gastrocnemius muscle and through the popliteal fossa. It then empties into the popliteal vein approx. 5 cm above the knee joint. Synonym: lesser saphenous vein; small saphenous vein

small cardiac vein

A surface vein of the heart that begins at the apex, runs along the right ventricle, and follows the coronary sulcus to the right to drain into the coronary sinus.

small saphenous vein

Short saphenous vein.

spermatic vein

In males, the veins that accompany the testicular artery and that drain the testis and epididymis. In the spermatic cord, the spermatic veins form the pampiniform plexus. After emerging from the deep inguinal ring, the spermatic veins merge into two veins, which continue to accompany the testicular artery. Eventually, the two spermatic veins merge into a single vein on each side, and the right spermatic vein empties into the inferior cava (below the renal vein), while the left spermatic vein empties into the left renal vein. Synonym: testicular vein

splenic vein

A large vein that drains the spleen and empties into the portal vein. Tributaries of the splenic vein include the short gastric, left gastroepiploic, and pancreatic veins.

stellate veins

Starlike venous plexuses on the surface of the kidney below its capsule.

subclavian vein

A large vein draining the arm and shoulder; it is the continuation of the axillary vein, beginning at the outer border of the first rib. Tributaries of the subclavian vein include the external jugular, dorsal scapular, and anterior jugular veins; the thoracic duct empties into the left subclavian vein, and the right lymphatic duct empties into the right subclavian vein. The subclavian vein ends by merging with the internal jugular vein to form the brachiocephalic vein.

superficial temporal vein

A network of veins that anastomose across the scalp and that collect into a single common vein, the superficial temporal vein. The superficial temporal vein then merges with the maxillary vein, inside the parotid gland, to form the posterior facial vein.

superior mesenteric vein

The vein that accompanies the superior mesenteric artery and drains the small intestine, cecum, ascending colon, and transverse colon. Under the neck of the pancreas, the superior mesenteric vein joins the splenic vein to form the portal vein. Tributaries of the superior mesenteric vein include the jejunal, ileal, ileocolic, right and middle colic, right gastroepiploic, and pancreaticoduodenal veins.

superior thyroid vein

The vein that accompanies the superior thyroid artery. Its tributaries include the superior laryngeal and cricothyroid veins, and it empties into the internal jugular vein (or, occasionally, the facial vein).

suprarenal vein

Adrenal vein.

systemic vein

A vein that is carrying deoxygenated blood (thus, it is not a pulmonary vein) and that empties into a vein and not into a capillary (thus, it is not a portal vein).

temporal vein

The deep, the middle, or the superficial temporal vein.

terminal vein

Vena terminalis.

testicular vein

Spermatic vein.

thalamostriate vein

The major vein draining the caudate nucleus and the thalamus of the brain. The thalamostriate vein merges with the choroid vein to form the internal cerebral vein.

thebesian vein

Any of the venules conveying blood from the myocardium to the atria or ventricles.

thyroid vein

The inferior, the middle, or the superior thyroid vein.

tibial vein

The anterior or the posterior tibial vein.

ulnar vein

A vein that drains blood from the forearm and the hand and that empties into the brachial vein.

umbilical vein

Along with the vitelline and the cardinal veins, the umbilical vein forms one of the three venous systems of the early embryo. The umbilical vein is a conduit for getting oxygenated blood from outside the embryo to the embryonic heart. In the fetus, deoxygenated blood is carried to the placenta from the internal iliac arteries via the right and left umbilical arteries. Oxygenated blood from the placenta is returned to the fetus in the single umbilical vein, which empties into the ductus venosus, a shunt that bypasses the fetal liver and connects directly to the inferior vena cava. Together, the umbilical vein and the umbilical arteries are the main contents of the umbilical cord.

VARICOSE VEINS IN LEG

varicose vein

A dilated vein. This condition may occur in almost any part of the body but is most common in the lower extremities and in the esophagus.

Etiology

The development of varicose veins of the legs is promoted and aggravated by pregnancy, obesity, genetics, chronic constipation, straining at stool, and occupations requiring prolonged standing. Esophageal varices are caused by portal hypertension that accompanies cirrhosis of the liver or mechanical obstruction and occlusion of hepatic veins.

Symptoms

Most varicose veins of the legs are asymptomatic, although they may be cosmetically undesirable. Esophageal varices and hemorrhoidal varices may bleed profusely. See: illustration

Treatment

In hemorrhage, elevation of the extremity and firm, gentle pressure over the wound will stop the bleeding. The patient should not be permitted to walk until the acute condition is controlled. Sclerotherapy, rubber band ligation, or octreotide may be used to control bleeding caused by hemorrhage from esophageal varices.

Patient care

The patient with lower extremity varicosities is taught to avoid anything that impedes venous return, such as wearing garters and tight girdles, crossing the legs at the knees, and prolonged sitting. After the legs have been elevated for 10 to 15 min, support hose are applied. The patient should not sit in a chair for longer than 1 hr at a time. Walking is encouraged for at least 5 min every hour. The patient should elevate the legs whenever possible, but no less than twice a day for 30 min each time, and should avoid prolonged standing. Exercise, esp. walking, is encouraged to promote the muscular contraction that moves blood through the veins and minimizes venous stasis. Signs of thrombophlebitis, a complication of varicose veins, include heat and local pain. If surgery is performed, elastic stockings or antithrombus devices are applied postoperatively, and the foot of the bed is elevated above the level of the heart. Analgesics are prescribed and administered as needed. Circulatory assessment (color and temperature of toes, pedal pulses) is carried out according to protocol or the surgeon’s orders. The patient is watched for complications such as bleeding, infection, and neurosensory problems. Overweight patients must lose weight.

vertebral vein

A vein draining the venous plexus that surrounds each vertebral artery. The vertebral vein leaves the sixth cervical transverse foramen and empties into the brachiocephalic vein.

vein of Vesalius

See: Vesalius, Andreas

vitelline vein

Along with the umbilical and the cardinal veins, the vitelline veins form one of the three venous systems of the early embryo. The vitelline veins return blood from the yolk sac. These veins are the precursors of many of the gut veins, including the portal system, and are focal structures in the developing liver.

vorticose vein

Any of four veins (two superior and two inferior) that receive blood from all parts of the choroid of the eye. They empty into posterior ciliary and superior ophthalmic veins.

innominate vein

One of a pair of veins which drain the head and upper chest by way of the JUGULAR and SUBCLAVIAN veins. The two innominate veins join to form the SUPERIOR VENA CAVA.