1. Inferior vena cava system. System of portal vein. Foetal circulation. Anastomoses between the portal and general systemic circulation

2. Autonomic nervous system.Central and peripheral parts of sympathetic and parasympathetic autonomic nervous system

3. Preparation of vessels and nerves of cavities

Lesson # 28

Theme 1. System of inferior vena cava. System of portal vein. Foetal circulation. Anastomoses between the portal and general systemic circulation

Venae cavae are the two largest veins in the body. These blood vessels carry de-oxygenated blood from various regions of the body to the right atrium of the heart. As the de-oxygenated blood is returned to the heart and continues to flow through the cardiac cycle, it is transported to the lungs where it becomes oxygenated. The blood then travels back to the heart and is pumped out to the rest of the body via the aorta. Oxygen depleted blood is returned to the heart again via the venae cavae.

The superior vena cava is located in the upper chest region and is formed by the joining of the brachiocephalic veins. It is bordered by heart structures such as the aorta and pulmonary artery. The inferior vena cava is formed by the joining of the common iliac veins which meet a little below the small of the back. The inferior vena cava travels along the spine and transports blood from the lower extremities of the body to the posterior region of the right atrium.

Function of the Venae Cavae

· Superior Vena Cava: Brings de-oxygenated blood from the head, neck, arm and chest regions of the body to the right atrium.

· Inferior Vena Cava: Brings de-oxygenated blood from the lower body regions (legs, back, abdomen and pelvis) to the right atrium.

The inferior vena cava (or IVC), also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart.

It is posterior to the abdominal cavity and runs alongside of the vertebral column on its right side (i.e. it is a retroperitoneal structure). It enters the right atrium at the lower right, back side of the heart.

The IVC is formed by the joining of the left and right common iliac veins and brings blood into the right atrium of the heart. It also anastomoses with the azygos vein system (which runs on the rght side of the vertebral column) and venous plexuses next to the spinal cord.

Because the IC is not centrally located, there are some asymmetries in drainage patterns. The gonadal veins and suprarenal veins drain into the IVC on the right side, but into the renal vein on the left side, which in turn drains into the IVC. By contrast, all the lumbar veins and hepatic veins usually drain directly into the IVC.

The tributaries of Inferior vena cava can be remembered using the mnemonic, "I Like To Rise So High", for Illiac vein (common), Lumbar vein, Testicular vein, Renal vein, Suprarenal vein and Hepatic vein.^[2]

Note that the vein that carries de-oxygenated blood from the upper half of the body is the superior vena cava

Inferior vena cava starts on level IV-V lumbar vertebrae by the confluence of left common iliac vein and right common iliac vein, to the right and beneath from bifurcation of aorta. It passes through special foramen in centrum tendineum of diaphragm into mediastinum and empties into right atrium.

There are parietal and visceral influxes of inferior vena cava.

The venæ cavæ and azygos veins, with their tributaries.

Parietal tributaries of inferior vena cava:

· lumbar veins are 3-4 pairs, which collect blood from areas according with ramification of lumbar arteries, they anastomose by right and left ascending lumbar veins;

inferior phrenic veins collect blood from areas according with ramification same name arteries.

·

Follow veins are the visceral tributaries of inferior vena cava:

· in male - right testicular vein starts from posterior testicle margin. Testicular vein forms pampiniform plexus which enters to composition of spermatic cord. Left testicular vein (also left ovaricа vein in famile) empties by right angle into left renal vein;

· in famile - right ovaric

· vein begins from ovary hilus;

· renal veins, pair, pass from kidney hilus and, anastomosing with lumbar veins, emptiy into inferior vena cava between lumbar vertebrae first and second;

· right suprarenal vein, exits from hilus of adrenal gland. Left suprarenal vein falls into left renal vein;

· hepatic veins (3-4) veins fall into inferior vena cava in area of same name sulcus in liver.

  The inferior vena cava (v. cava inferior), returns to the heart the blood from the parts below the diaphragm. It is formed by the junction of the two common iliac veins, on the right side of the fifth lumbar vertebra. It ascends along the front of the vertebral column, on the right side of the aorta, and, having reached the liver, is continued in a groove on its posterior surface. It then perforates the diaphragm between the median and right portions of its central tendon; it subsequently inclines forward and medialward for about 2.5 cm., and, piercing the fibrous pericardium, passes behind the serous pericardium to open into the lower and back part of the right atrium. In front of its atrial orifice is a semilunar valve, termed the valve of the inferior vena cava: this is rudimentary in the adult, but is of large size and exercises an important function in the fetus (see page 540).

Relations.—The abdominal portion of the inferior vena cava is in relation in front, from below upward, with the right common iliac artery, the mesentery, the right internal testicular artery, the inferior part of the duodenum, the pancreas, the common bile duct, the portal vein, and the posterior surface of the liver; the last partly overlaps and occasionally completely surrounds it; behind, with the vertebral column, the right Psoas major, the right crus of the diaphragm, the right inferior phrenic, suprarenal, renal and lumbar arteries, right sympathetic trunk and right celiac ganglion, and the medial part of the right suprarenal gland; on the right side, with the right kidney and ureter; on the left side, with the aorta, right crus of the diaphragm, and the caudate lobe of the liver.

  The thoracic portion is only about 2.5 cm. in length, and is situated partly inside and partly outside the pericardial sac. The extrapericardial part is separated from the right pleura and lung by a fibrous band, named the right phrenicopericardiac ligament. This ligament, often feebly marked, is attached below to the margin of the vena-caval opening in the diaphragm, and above to the pericardium in front of and behind the root of the right lung. The intrapericardiac part is very short, and is covered antero-laterally by the serous layer of the pericardium.

Peculiarities.—In Position.—This vessel is sometimes placed on the left side of the aorta, as high as the left renal vein, and, after receiving this vein, crosses over to its usual position on the right side; or it may be placed altogether on the left side of the aorta, and in such a case the abdominal and thoracic viscera, together with the great vessels, are all transposed.

Point of Termination.—Occasionally the inferior vena cava joins the azygos vein, which is then of large size. In such cases, the superior vena cava receives the whole of the blood from the body before transmitting it to the right atrium, except the blood from the hepatic veins, which passes directly into the right atrium.

Tributaries.—The inferior vena cava receives the following veins:

Lumbar.

Renal.

Inferior Phrenic.

Right Spermatic or Ovarian.

Suprarenal.

Hepatic.

  The Lumbar Veins (vv. lumbales) four in number on each side, collect the blood by dorsal tributaries from the muscles and integument of the loins, and by abdominal tributaries from the walls of the abdomen, where they communicate with the epigastric veins. At the vertebral column, they receive veins from the vertebral plexuses, and then pass forward, around the sides of the bodies of the vertebræ, beneath the Psoas major, and end in the back part of the inferior cava. The left lumbar veins are longer than the right, and pass behind the aorta. The lumbar veins are connected together by a longitudinal vein which passes in front of the transverse processes of the lumbar vertebræ, and is called the ascending lumbar; it forms the most frequent origin of the corresponding azygos or hemiazygos vein, and serves to connect the common iliac, iliolumbar, and azygos or hemiazygos veins of its own side of the body.

  The Testicular veins (vv. spermaticæ) emerge from the back of the testis, and receive tributaries from the epididymis; they unite and form a convoluted plexus, called the pampiniform plexus, which constitutes the greater mass of the spermatic cord; the vessels composing this plexus are very numerous, and ascend along the cord, in front of the ductus deferens. Below the subcutaneous inguinal ring they unite to form three or four veins, which pass along the inguinal canal, and, entering the abdomen through the abdominal inguinal ring, coalesce to form two veins, which ascend on the Psoas major, behind the peritoneum, lying one on either side of the internal testicular artery. These unite to form a single vein, which opens on the right side into the inferior vena cava, at an acute angle; on the left side into the left renal vein, at a right angle. The testicular veins are provided with valves. 107 The left testicular vein passes behind the iliac colon, and is thus exposed to pressure from the contents of that part of the bowel.

  The Ovarian Veins (vv. ovaricæ) correspond with the spermatic in the male; they form a plexus in the broad ligament near the ovary and uterine tube, and communicate with the uterine plexus. They end in the same way as the testicular veins in the male. Valves are occasionally found in these veins. Like the uterine veins,

they become much enlarged during pregnancy.

Testicular veins.

  The Renal Veins (vv. renales) are of large size, and placed in front of the renal arteries. The left is longer than the right, and passes in front of the aorta, just below the origin of the superior mesenteric artery. It receives the left testicular and left inferior phrenic veins, and, generally, the left suprarenal vein. It opens into the inferior vena cava at a slightly higher level than the right.

  The Suprarenal Veins (vv. suprarenales) are two in number: the right ends in the inferior vena cava; the left, in the left renal or left inferior phrenic vein.

  The Inferior Phrenic Veins (vv. phrenicæ inferiores) follow the course of the inferior phrenic arteris; the right ends in the inferior vena cava; the left is often represented by two branches, one of which ends in the left renal or suprarenal vein, while the other passes in front of the esophageal hiatus in the diaphragm and opens into the inferior vena cava.

  The Hepatic Veins (vv. hepaticæ) commence in the substance of the liver, in the terminations of the portal vein and hepatic artery, and are arranged in two groups, upper and lower. The upper group usually consists of three large veins, which converge toward the posterior surface of the liver, and open into the inferior vena cava, while that vessel is situated in the groove on the back part of the liver. The veins of the lower group vary in number, and are of small size; they come from the right and caudate lobes. The hepatic veins run singly, and are in direct contact with the hepatic tissue. They are destitute of valves.

The portal vein and its tributaries.

Vena portae hepatis is situated in thickness of hepatoduodenal ligament between ductus choledochus and proper hepatic artery (formula of their position DVA – from right to left). It originates behind head of pancreas by the confluence of superior, inferior mesenteric veinc and splenic vein. It collects venous blood from odd organs of abdominal cavity, except liver. Vena portae receives cystic vein, right and left gastric veins and prepyloric vein closely to liver hilus. Paraumbilical veins fall into portal vein in liver hilus.

There are cava-caval and porto-caval anastomoses between systems of portal vein, superior and inferior vanea cavae (see table on the next page).

The portal system includes all the veins which drain the blood from the abdominal part of the digestive tube (with the exception of the lower part of the rectum) and from the spleen, pancreas, and gall-bladder. From these viscera the blood is conveyed to the liver by the portal vein. In the liver this vein ramifies like an artery and ends in capillary-like vessels termed sinusoids, from which the blood is conveyed to the inferior vena cava by the hepatic veins. From this it will be seen that the blood of the portal system passes through two sets of minute vessels, viz., (a) the capillaries of the digestive tube, spleen, pancreas, and gall-bladder; and (b) the sinusoids of the liver. In the adult the portal vein and its tributaries are destitute of valves; in the fetus and for a short time after birth valves can be demonstrated in the tributaries of the portal vein; as a rule they soon atrophy and disappear, but in some subjects they persist in a degenerate form.

  The portal vein (vena portæ) is about 8 cm. in length, and is formed at the level of the second lumbar vertebra by the junction of the superior mesenteric and lienal veins, the union of these veins taking place in front of the inferior vena cava and behind the neck of the pancreas. It passes upward behind the superior part of the duodenum and then ascends in the right border of the lesser omentum to the right extremity of the porta hepatis, where it divides into a right and a left branch, which accompany the corresponding branches of the hepatic artery into the substance of the liver. In the lesser omentum it is placed behind and between the common bile duct and the hepatic artery, the former lying to the right of the latter. It is surrounded by the hepatic plexus of nerves, and is accompanied by numerous lymphatic vessels and some lymph glands. The right branch of the portal vein enters the right lobe of the liver, but before doing so generally receives the cystic vein. The left branch, longer but of smaller caliber than the right, crosses the left sagittal fossa, gives branches to the caudate lobe, and then enters the left lobe of the liver. As it crosses the left sagittal fossa it is joined in front by a fibrous cord, the ligamentum teres (obliterated umbilical vein), and is united to the inferior vena cava by a second fibrous cord, the ligamentum venosum (obliterated ductus

venosus).

Tributaries.—The tributaries of the portal vein are:

Lienal.

Pyloric.

Superior Mesenteric.

Cystic.

Coronary.

Parumbilical.

  The Lienal Vein (v. lienalis; splenic vein) commences by five or six large branches which return the blood from the spleen. These unite to form a single vessel, which passes from left to right, grooving the upper and back part of the pancreas, below the lineal artery, and ends behind the neck of the pancreas by uniting at a right angle with the superior mesenteric to form the portal vein. The lienal vein is of large size, but is not tortuous like the artery.

Tributaries.—The lineal vein receives the short gastric veins, the left gastroepiploic vein, the pancreatic veins, and the inferior mesenteric veins.

  The short gastric veins (vv. gastricæ breves), four or five in number, drain the fundus and left part of the greater curvature of the stomach, and pass between the two layers of the gastrolienal ligament to end in the lienal vein or in one of its large tributaries.

  The left gastroepiploic vein (v. gastroepiploica sinistra) receives branches from the antero-superior and postero-inferior surfaces of the stomach and from the greater omentum; it runs from right to left along the greater curvature of the stomach and ends in the commencement of the lienal vein.

  The pancreatic veins (vv. pancreaticæ) consist of several small vessels which drain the body and tail of the pancreas, and open into the trunk of the lienal vein.

The inferior mesenteric vein (v. mesenterica inferior) returns blood from the rectum and the sigmoid, and descending parts of the colon. It begins in the rectum as the superior hemorrhoidal vein, which has its origin in the hemorrhoidal plexus, and through this plexus communicates with the middle and inferior hemorrhoidal veins. The superior hemorrhoidal vein leaves the lesser pelvis and crosses the left common iliac vessels with the superior hemorrhoidal artery, and is continued upward as the inferior mesenteric vein. This vein lies to the left of its artery, and ascends behind the peritoneum and in front of the left Psoas major; it then passes behind the body of the pancreas and opens into the lienal vein; sometimes it ends in the angle of union of the lienal and superior mesenteric veins.

Tributaries.—The inferior mesenteric vein receives the sigmoid veins from the sigmoid colon and iliac colon, and the left colic vein from the descending colon and left colic flexure.

  The Superior Mesenteric Vein (v. mesenterica superior) returns the blood from the small intestine, from the cecum, and from the ascending and transverse portions of the colon. It begins in the right iliac fossa by the union of the veins which drain the terminal part of the ileum, the cecum, and vermiform process, and ascends between the two layers of the mesentery on the right side of the superior mesenteric artery. In its upward course it passes in front of the right ureter, the inferior vena cava, the inferior part of the duodenum, and the lower portion of the head of the pancreas. Behind the neck of the pancreas it unites with the lienal vein to form the portal vein.

Tributaries.—Besides the tributaries which correspond with the branches of the superior mesenteric artery, viz., the intestinal, ileocolic, right colic, and middle colic veins, the superior mesenteric vein is joined by the right gastroepiploic and pancreaticoduodenal veins.

  The right gastroepiploic vein (v. gastroepiploica dextra) receives branches from the greater omentum and from the lower parts of the antero-superior and posteroinferior surfaces of the stomach; it runs from left to right along the greater curvature of the stomach between the two layers of the greater omentum.

  The pancreaticoduodenal veins (vv. pancreaticoduodenales) accompany their corresponding arteries; the lower of the two frequently joins the right gastroepiploic vein.

  The Coronary Vein (v. coronaria ventriculi; gastric vein) derives tributaries from both surfaces of the stomach; it runs from right to left along the lesser curvature of the stomach, between the two layers of the lesser omentum, to the esophageal opening of the stomach, where it receives some esophageal veins. It then turns backward and passes from left to right behind the omental bursa and ends in the portal vein.

  The Pyloric Vein is of small size, and runs from left to right along the pyloric portion of the lesser curvature of the stomach, between the two layers of the lesser omentum, to end in the portal vein.

  The Cystic Vein (v. cystica) drains the blood from the gall-bladder, and, accompanying the cystic duct, usually ends in the right branch of the portal vein.

Parumbilical Veins (vv. parumbilicales).—In the course of the ligamentum teres of the liver and of the middle umbilical ligament, small veins (parumbilical) are found which establish an anastomosis between the veins of the anterior abdominal wall and the portal, hypogastric, and iliac veins. The best marked of these small veins is one which commences at the umbilicus and runs backward and upward in, or on the surface of, the ligamentum teres between the layers of the falciform ligament to end in the left portal vein.

  Collateral venous circulation to relieve portal obstruction in the liver may be effected by communications between (a) the gastric veins and the esophageal veins which often project as a varicose bunch into the stomach, emptying themselves into the hemiazygos vein; (b) the veins of the colon and duodenum and the left renal vein; (c) the accessory portal system of Sappey, branches of which pass in the round and falciform ligaments (particularly the latter) to unite with the epigastric and internal mammary veins, and through the diaphragmatic veins with the azygos; a single large vein, shown to be a parumbilical vein, may pass from the hilus of the liver by the round ligament to the umbilicus, producing there a bunch of prominent varicose veins known as the caput medusæ; (d) the veins of Retzius, which connect the intestinal veins with the inferior vena cava and its retroperitoneal branches; (e) the inferior mesenteric veins, and the hemorrhoidal veins that open into the hypogastrics; (f) very rarely the ductus venosus remains patent, affording a direct connection between the portal vein and the inferior vena cava.

Anastomoses between the superior and inferior venae cavae systems

System	Veins	Veins	Position of anastomose
V. cava superior And v. cava inferior	v. epigastrica superior (tributary of the internal thoracic vein) and v. Thoracoepigastrica (tributary of the subclavian vein)	v. epigastrica inferior (tributary of the external iliac vein) and v. Epigastrica superficialis (tributary of the femoral vein)	In anterior abdominal wall round the navel
V. cava superior And v. Cava inferior	vv. azygos and hemiazygos	vv. lumbales	On posterior abdominal wall
V. cava superior And v. Cava inferior	Rr. spinales (tributary of the vv. Intercostales posteriores)	Rr. spinales (tributary of the vv. Lumbales)	Form internal and external vertebral plexus

Anastomoses between the superior and inferior venae cavae

and portal vein systems

V. cava superior and v. Portae	v. epigastrica superior (tributary of the internal thoracic vein)	Vv. paraumbilicales	In anterior abdominal wall round the navel
V. cava superior and v. Portae	Vv. esophageales (tributary of the azygos vein)	v. gastrica sinistra	Near gastric cardia
V. cava inferior and v. Portae	v. epigastrica inferior (tributary of the external iliac vein)	Vv. paraumbilicales	In anterior abdominal wall
V. cava inferior and v. Portae	V. rectalis media (tributary of the internal iliac vein)	V. rectalis superior (tributary of the inferior mesenteric vein)	Plexus venosus rectalis
V. cava inferior and v. Portae	Vv. lumbales	Vv. mesenterica superior and inferior	In thickness of ascending and descending colon

Circulatory system of the foetus has a row of peculiarities that differ from adult one:

- arterial blood reaches the foetus through umbilical vein from placenta;

- exclusive of umbilical vein, a blood in vessels is mixed;

- venous (Аranti) duct functions between umbilical and inferior vena cava by veins;

- blood from inferior vena cava gets from right atrium through the ovale foramen into left atrium;

- pulmonary circulation does not function;

- arterial (Botalova) duct functions between aortic arch and pulmonary trunk, through the which blood from pulmonary blood circle passes in systemic circulation;

- more oxygenated blood supplies head, neck, upper limbs and superior part of torso. Inferior part of trunk and lower limbs supplied by mixed blood, which is insufficiently saturated by oxygen, that's why these body portions of foetus fall behind in development in compare of head and upper part of torso.

After birth breath starts and pulmonary circulation begins to function. Umbilical vessels overgrow in 6-7 days, Botali duct - in 9-10 days and oval foramen in interatrial wall – in 30 days after birth

Peculiarities in the Vascular System in the Fetus The chief peculiarities of the fetal heart are the direct communication between the atria through the foramen ovale, and the large size of the valve of the inferior vena cava. Among other peculiarities the following may be noted. (1) In early fetal life the heart lies immediately below the mandibular arch and is relatively large in size. As development proceeds it is gradually drawn within the thorax, but at first it lies in the middle line; toward the end of pregnancy it gradually becomes oblique in direction. (2) For a time the atrial portion exceeds the ventricular in size, and the walls of the ventricles are of equal thickness: toward the end of fetal life the ventricular portion becomes the larger and the wall of the left ventricle exceeds that of the right in thickness. (3) Its size is large as compared with that of the rest of the body, the proportion at the second month being 1 to 50, and at birth, 1 to 120, while in the adult the average is about 1 to 160.

  The foramen ovale, situated at the lower part of the atrial septum, forms a free communication between the atria until the end of fetal life. A septum (septum secundum) grows down from the upper wall of the atrium to the right of the primary septum in which the foramen ovale is situated; shortly after birth it fuses with the primary septum and the foramen ovale is obliterated.

  The valve of the inferior vena cava serves to direct the blood from that vessel through the foramen ovale into the left atrium.

  The peculiarities in the arterial system of the fetus are the communication between the pulmonary artery and the aorta by means of the ductus arteriosus, and the continuation of the hypogastric arteries as the umbilical arteries to the placenta.

  The ductus arteriosus is a short tube, about 1.25 cm. in length at birth, and of the diameter of a goose-quill. In the early condition it forms the continuation of the pulmonary artery, and opens into the aorta, just beyond the origin of the left subclavian artery; and so conducts the greater amount of the blood from the right ventricle into the aorta. When the branches of the pulmonary artery have become larger relatively to the ductus arteriosus, the latter is chiefly connected to the left pulmonary artery.

  The hypogastric arteries run along the sides of the bladder and thence upward on the back of the anterior abdominal wall to the umbilicus; here they pass out of the abdomen and are continued as the umbilical arteries in the umbilical cord to the placenta. They convey the fetal blood to the placenta.

  The peculiarities in the venous system of the fetus are the communications established between the placenta and the liver and portal vein, through the umbilical vein; and between the umbilical vein and the inferior vena cava through the ductus venosus.

Fetal Circulation

The fetal blood is returned from the placenta to the fetus by the umbilical vein. This vein enters the abdomen at the umbilicus, and passes upward along the free margin of the falciform ligament of the liver to the under surface of that organ, where it gives off two or three branches, one of large size to the left lobe, and others to the lobus quadratus and lobus caudatus. At the porta hepatis (transverse fissure of the liver) it divides into two branches: of these, the larger is joined by the portal vein, and enters the right lobe; the smaller is continued upward, under the name of the ductus venosus, and joins the inferior vena cava. The blood, therefore, which traverses the umbilical vein, passes to the inferior vena cava in three different ways. A considerable quantity circulates through the liver with the portal venous blood, before entering the inferior vena cava by the hepatic veins; some enters the liver directly, and is carried to the inferior cava by the hepatic veins; the remainder passes directly into the inferior vena cava through the ductus venosus.

  In the inferior vena cava, the blood carried by the ductus venosus and hepatic veins becomes mixed with that returning from the lower extremities and abdominal wall. It enters the right atrium, and, guided by the valve of the inferior vena cava, passes through the formen ovale into the left atrium, where it mixes with a small quantity of blood returned from the lungs by the pulmonary veins. From the left atrium it passes into the left ventricle; and from the left ventricle into the aorta, by means of which it is distributed almost entirely to the head and upper extremities, a small quantity being probably carried into the descending aorta. From the head and upper extremities the blood is returned by the superior vena cava to the right atrium, where it mixes with a small portion of the blood from the inferior vena cava. From the right atrium it descends into the right ventricle, and thence passes into the pulmonary artery. The lungs of the fetus being inactive, only a small quantity of the blood of the pulmonary artery is distributed to them by the right and left pulmonary arteries, and returned by the pulmonary veins to the left atrium: the greater part passes through the ductus arteriosus into the aorta, where it mixes with a small quantity of the blood transmitted by the left ventricle into the aorta. Through this vessel it descends, and is in part distributed to the lower extremities and the viscera of the abdomen and pelvis, but the greater amount is conveyed by the umbilical arteries to the placenta.

The lumbar ganglia of lumbar department of sympathetic trunk are represented by 4-5 ganglia and interganglionic branches. These ganglia are found on anterior-lateral surface of lumbar vertebrae bodies. The lumbar ganglia of right and left sympathetic trunk unite between oneself by communicating branches. The first and second lumbar ganglia approach the communicating white branches. Each ganglion gives off the gray communicating branches to lumbar spinal nerves and lumbar splanchnic nerves, which pass to abdominal plexus and have both preganglionic and postganglionic nervous fibers.

The abdominal portion of the sympathetic trunk Celiacplexus continues around abdominal aorta, formingabdominal aortic plexus. It innervates kidney, suprarenal glands,ureters and testicles (ovaries).

Inferiormesenteric plexusstarts closely to inferior mesenteric artery. Itinnervates descending and sigmoid colon, superior part of the rectum.Superior hypogastric plexuslocated inpoint of aortic bifurcation. It receives splanchnic nerves from lower lumbarand upper sacral sympathetic ganglia. Superior hypogastric plexus divides intoright and leftinferior hypogastricplexuseslower then promontorium. Inferior hypogastric plexus reaches theorgans and tissues of lesser pelvis with arterial branches from internal iliacartery. It innervates seminal vesicles, prostate (male) uterus, Fallopiantubes, vagina (female), also rectum,urinarybladder.

Abdominalpart of vagus nerve is represented by anterior and posterior vagal trunks,which originate from esophageal plexus.Anteriorvagal trunklocated on front surface of the stomach and gives branchesgives off the anterior gastric and hepatic branches.Posterior vagal trunksupplies back gastric wall, and gives offcoeliac branches to reach coeliac plexus. Then fibers of vagus nerve withsympathetic fibers supply the liver, spleen, pancreas, kidneys, small and largeintestine (includingaupper department of descendingcolon).

 Thegastric Branches(rami gastrici) are distributed to the stomach.The right vagus forms theposterior gastric plexuson thepostero-inferior surface of the stomach and the left theanterior gastricplexuson the antero-superior surface.

  Theceliac Branches(rami cæliaci) are mainly derived from theright vagus: they join the celiac plexus and through it supply branches to thepancreas, spleen, kidneys, suprarenal bodies, and intestine.

  Thehepatic Branches(rami hepatici)arisefrom the leftvagus: they join the hepatic plexus and through it are conveyed to the liver.

Thegreat plexuses of the sympathetic are aggregations of nerves and ganglia,situated in the thoracic, abdominal, and pelvic cavities, and named thecardiac,celiac,andhypogastric plexuses.They consist not only ofsympathetic fibers derived from the ganglia, but of fibers from the medullaspinalis, which are conveyed through the white rami communicantes. From theplexuses branches are given to the thoracic, abdominal, and pelvic viscera.

Theceliac Plexus (Plexus Cœliacus; Solar Plexus) (

Theceliac ganglia with the sympathetic plexuses of the abdominal viscera radiatingfrom the ganglia.

  The lienal plexus (plexus lienalis; splenic plexus) is formed bybranches from the celiac plexus, the left celiac ganglion, and from the rightvagus nerve. It accompanies the lienal artery to the spleen, giving off, in itscourse, subsidiary plexuses along the various branches of the artery.

  The superior gastric plexus (plexus gastricus superior; gastric orcoronary plexus) accompanies the left gastric artery along the lessercurvature of the stomach, and joins with branches from the left vagus.

  The suprarenal plexus (plexus suprarenalis) is formed by branchesfrom the celiac plexus, from the celiac ganglion, and from the phrenic andgreater splanchnic nerves, a ganglion being formed at the point of junctionwith the latter nerve. The plexus supplies the suprarenal gland, beingdistributed chiefly to its medullary portion; its branches are remarkable fortheir large size in comparison with that of the organ they supply.

  The renal plexus (plexus renalis) is formed by filaments from the celiacplexus, the aorticorenal ganglion, and the aortic plexus. It is joined also bythe smallest splanchnic nerve. The nerves from these sources, fifteen or twentyin number, have a few ganglia developed upon them. They accompany the branchesof the renal artery into the kidney; some filaments are distributed to thespermatic plexus and, on the right side, to the inferior vena cava.

  The spermatic plexus (plexus spermaticus) is derived from the renalplexus, receiving branches from the aortic plexus. It accompanies the internalspermatic artery to the testis. In the female, the ovarian plexus (plexusarteriæovaricæ)arisesfrom the renal plexus, and isdistributed to the ovary, and fundus of the uterus.

  The superior mesenteric plexus (plexus mesentericus superior) is acontinuation of the lower part of the celiac plexus, receiving a branch fromthe junction of the right vagus nerve with the plexus. It surrounds thesuperior mesenteric artery, accompanies it into the mesentery, and divides intoa number of secondary plexuses, which are distributed to all the parts suppliedby the artery, viz., pancreatic branches to the pancreas; intestinal branchesto the small intestine; and ileocolic, right colic, and middle colic branches,which supply the corresponding parts of the great intestine. The nervescomposing this plexus are white in color and firm in texture; in the upper partof the plexus close to the origin of the superior mesenteric artery is aganglion (ganglion mesentericum superius).

  The abdominal aortic plexus(plexus aorticus abdominalis; aortic plexus)is formed by branches derived, on either side, from the celiac plexus andganglia, and receives filaments from some of the lumbar ganglia. It is situatedupon the sides and front of the aorta, between the origins of the superior andinferior mesenteric arteries. From this plexus arise part of the spermatic, theinferior mesenteric, and the hypogastric plexuses; it also distributesfilaments to the inferior vena cava.

  The inferior mesenteric plexus(plexus mesentericus inferior) isderived chiefly from the aortic plexus. It surrounds the inferior mesentericartery, and divides into a number of secondary plexuses, which are distributedto all the parts supplied by the artery, viz., the left colic and sigmoid plexuses,which supply the descending and sigmoid parts of the colon; and the superior hemorrhoidal plexus,which supplies the rectum and joins inthe pelvis with branches from the pelvic plexuses.

Thehypogastric Plexus (Plexus Hypogastricus)Parasympatheticnerves ofthe pelvis origin from nuclei in sacral segments s_ii- s_ivof spinal cord.preganglionicfibers[pelvic splanchnicnerves]pass to theterminal ganglia near organs. Postganglionic fibers innervate urinary bladder,reproductiveorgans,lower half of descending colon,sygmoid colon and rectum.

Thegreat plexuses of the sympathetic are aggregations of nerves and ganglia,situated in the thoracic, abdominal, and pelvic cavities, and named thecardiac,celiac,andhypogastric plexuses.they consist not only ofsympathetic fibers derived from the ganglia, but of fibers from the medullaspinalis, which are conveyed through the white rami communicantes. From theplexuses branches are given to the thoracic, abdominal, and pelvic viscera.

Thepelvic plexuses(838).—thepelvicplexuses supply the viscera of the pelvic cavity, and are situated at the sidesof the rectum in the male, and at the sides of the rectum and vagina in thefemale. They are formed on either side by a continuation of the hypogastricplexus, by the sacral sympathetic efferent fibers from the second, third, andfourth sacral nerves, and by a few filaments from the first two sacral ganglia.at the points of junction of these nerves small ganglia are found. From theseplexuses numerous branches are distributed to the viscera of the pelvis. Theyaccompany the branches of the hypogastric artery.

  The middle hemorrhoidal plexus(plexus hæmorrhoidalis medius)arisesfrom the upper part of the pelvic plexus. It supplies the rectum, and joinswith branches of the superior hemorrhoidal plexus.

Parietal branches

Lesser curvature of stomach

a. hepatica propria (rr. Dexter et sinister)

Lien

. mesenterica inferior L-III

The celiac artery and its branches; the stomach has been raised and the peritoneum removed.

  The cystic artery (a. cystica), usually a branch of the right hepatic, passes downward and forward along the neck of the gall-bladder, and divides into two branches, one of which ramifies on the free surface, the other on the attached surface of the gall-bladder.

hilus of that organ between the two layers of the phrenicolienal ligament to be distributed to the tissues of the spleen; some are given to the pancreas, while others pass to the greater curvature of the stomach between the layers of the gastrolienal ligament. Its branches are:Pancreatic.

Left Gastroepiploic.

The superior mesenteric artery and its branches.

  The superior mesenteric artery (a. mesenterica superior) is a large vessel which supplies the whole length of the small intestine, except the superior part of the duodenum; it also supplies the cecum and the ascending part of the colon and about one-half of the transverse part of the colon. It arises from the front of the aorta, about 1.25 cm. below the celiac artery, and is crossed at its origin by the lienal vein and the neck of the pancreas. It passes downward and forward, anterior to the processus uncinatus of the head of the pancreas and inferior part of the duodenum, and descends between the layers of the mesentery to the right iliac fossa, where, considerably diminished in size, it anastomoses with one of its own branches, viz., the ileocolic. In its course it crosses in front of the inferior vena cava, the right ureter and Psoas major, and forms an arch, the convexity of which is directed foward and downward to the left side, the concavity backward and upward to the right. It is accompanied by the superior mesenteric vein, which lies to its right side, and it is surrounded by the superior mesenteric plexus of nerves.

Branches.—Its branches are:

Ileocolic.

Right Colic.

  The Inferior Pancreaticoduodenal Artery (a. pancreaticoduodenalis inferior) is given off from the superior mesenteric or from its first intestinal branch, opposite the upper border of the inferior part of the duodenum. It courses to the right between the head of the pancreas and duodenum, and then ascends to anastomose with the superior pancreaticoduodenal artery. It distributes branches to the head of the pancreas and to the descending and inferior parts of the duodenum.

intestini tenuis) arise from the convex side of the superior mesenteric artery. They are usually from twelve to fifteen in number, and are distributed to the jejunum and ileum. They run nearly parallel with one another between the layers of the mesentery, each vessel dividing into two branches, which unite with adjacent branches, forming a series of arches, the convexities of which are directed toward the intestine.  The Ileocolic Artery (a. ileocolica) is the lowest branch arising from the concavity of the superior mesenteric artery. It passes downward and to the right behind the peritoneum toward the right iliac fossa, where it divides into a superior and an inferior branch; the inferior anastomoses with the end of the superior mesenteric artery, the superior with the right colic artery.