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Abdominal aorta, inferior vena cava and their branches
Vascular
Abdominal aorta, inferior vena cava and their branches
Aorta and inferior vena cava and the principal branches or tributaries Hepatic veins
Phrenic artery
Harold Ellis Coeliac axis
Left renal artery and vein
Superior mesenteric artery
Abstract The aorta enters the abdomen at T12 between the crura of the diaphragm and ends at L4 by dividing into the common iliac arteries, which in turn divide into the external and internal iliacs. The external gives no branches apart from just above its termination into the common femoral artery – the inferior epigastric and deep circumflex iliac. The internal iliac artery gives off numerous visceral and body wall branches to the pelvic organs, pelvic wall, perineum and buttock region. The aorta gives off visceral branches anteriorly (coeliac, superior and inferior epigastrics) and laterally (suprarenal, renal and gonadal – testicular and ovarian – as well as inferior phrenic, four lumbar and the middle sacral artery). The inferior vena cava commences by the junction of the common iliac veins in front of L5. It lies immediately to the right of the aorta but is considerably longer because it ascends to the right crus of the diaphragm to pierce the central tendon of the diaphragm at T8, having deeply grooved the posterior aspect of the liver at its bare area. The tributaries of the inferior vena cava differ from the branches of the aorta in two respects. First, those corresponding to the anterior visceral branches of the aorta form the portal vein, which passes into the liver at the porta hepatis. Venous blood then returns to the inferior vena cava via the right, middle, left and accessory hepatic veins. Second, the suprarenal and gonadal veins on the left side, unlike those on the right, which drain directly into the inferior vena cava, empty into the left renal vein, which then crosses the front of the aorta to enter the inferior vena cava.
Inferior mesenteric artery
Left testicular (or ovarian) artery and vein
Lumbar artery and vein Median sacral artery
Common Internal
Iliac artery and vein
External
Figure 1
the splenic vein, the left renal vein, the third part of the duo denum and, below this, the peritoneum of the posterior abdom inal wall and loops of small intestine. The aorta can be marked out by a line running in the midline from just above the transpyloric plane to the supracristal line, which joins the iliac crests. It can be palpated by firm midline pressure above the supracristal line and, indeed, seen to pulsate in thin patients. Branches of the aorta There are three anterior branches to the abdominal viscera: the coeliac axis (at the commencement of the abdominal aorta at T12) which divides into the hepatic, splenic and left gastric branches; the superior mesenteric artery at L1; and the inferior mesenteric artery at L3. Three branches to the viscera derive from the lateral sides of the aorta, close to each other at about the transpyloric plane: the right and left renal arteries; the suprarenal arteries just above the renal origins; and the gonadal arteries (ovarian or testicular) just below the renals. A series of branches supply muscles and soft tissues: the in ferior phrenic, running over the crus of the diaphragm on each side (an important supply to the diaphragm); the lumbar arteries (four on each side); and the median sacral artery, derived from the aortic bifurcation, a small vessel running over the front of the sacrum.
Keywords aorta; common, external and internal iliac vessels; hepatic veins; inferior vena cava; suprarenal and gonadal vessels
The abdominal aorta (Figure 1) The thoracic aorta passes through the diaphragm between its crura and beneath the median arcuate ligament immediately in front of the 12th thoracic vertebra. It passes downwards in front of the bodies of the lumbar vertebrae to end, very constantly, in front of the body of L4 to divide into the right and left common iliac arteries. It is crossed posteriorly by the left lumbar veins as they pass to the inferior vena cava, and these may be injured in mobilization of the aorta. To its right lies the inferior vena cava, to its left it overlaps the left lumbar sympathetic chain, and on either side lies the para-aortic chain of lymph nodes; importantly, these are the nodes of drainage of the testis and ovary. Anteriorly, the aorta lies behind, successively: the body of the pancreas with
The common iliac arteries These originate at the aortic bifurcation and pass along the medial edge of psoas, in close relationship to the vein, to end in front of the sacroiliac joint by bifurcating into the internal and external iliac. This is an important landmark for surgeons;
Harold Ellis, CBE, MCh, FRCS, was Professor of Surgery at Westminster Medical School until 1989. Since then he has taught anatomy, first at Cambridge and now at Guy’s Hospital, London.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 8:6
Left suprarenal artery and vein
253
© 2007 Published by Elsevier Ltd.
Vascular
very constantly the ureter crosses the external iliac artery at the bifurcation and then runs down on the anterior aspect of the internal iliac artery.
The hepatic and portal veins Right, middle and left hepatic veins draining into inferior vena cava
The external iliac artery continues on psoas along the pelvic brim to pass beneath the inguinal ligament to become the common femoral artery. Each is accompanied by its vein, but (fortunately for surgeons) remains superficial to the vein on either side (Figure 1). The external iliac artery gives off no branches until near its termination, when it gives rise to two vessels, which help supply the anterior abdominal wall – the inferior epigastric and the deep circumflex iliac arteries.
Portal vein
The internal iliac artery passes into the pelvis and soon divides into numerous branches in a variable manner. However, the branches themselves are constant, and are described below. The visceral branches supply the pelvic organs. In the male, the superior vesical artery supplies the bladder; the inferior ves ical the bladder base, prostate and seminal vesicles; and the middle rectal the rectum and upper anal canal. In the female, there is, in addition, the uterine artery, which passes transversely across to the uterus and crosses the ureter, and is therefore in danger of damage at this point. Also in the female, the inferior vesical artery is replaced by the vaginal artery, which passes the vagina and anastomoses with the uterine artery. The body wall branches supply the soft tissues lining the pelvis, perineum and buttock. These comprise the ilio-lumbar, lateral sacral, superior and inferior gluteal, obturator, and in ternal pudendal arteries.
Splenic vein Superior–inferior mesenteric veins Figure 2
area of the liver. Here it receives its largest tributaries: the three hepatic veins. The tributaries of the inferior vena cava The iliac veins run with their arteries, and the internal and external iliacs have tributaries that accompany their arterial branches. There are two important differences between the branches of the aorta and the tributaries of the inferior vena cava. First, obviously the veins which accompany the coeliac, and the superior and inferior mesenteric arteries are collected into the portal system of veins; the splenic vein and the superior mesenteric vein join behind the pancreas to form the portal vein, while the inferior mesenteric vein drains into the splenic vein. The portal blood, having passed through its hepatic capillaries, reunites with the hepatic venous system, which drains into the inferior vena cava via the large right, middle and left hepatic veins together with a variable number of accessory hepatic veins as the inferior vena cava lies in its deep groove on the posterior aspect of the liver (Figure 2). Second, although the lateral visceral veins on the right side (the suprarenal, renal and gonadal) drain directly into the inferior vena cava, the suprarenal and gonadal (ovarian or testicular) veins on the left side drain into the left renal vein, which has a long course as it passes across the anterior aspect of the aorta immediately inferior to the origin of the superior mesenteric artery (Figure 1). ◆
The inferior vena cava (Figure 1) This vein is considerably longer than the abdominal aorta. It commences inferiorly by the confluence of the common iliac veins behind the right common iliac artery in front of the body of L5. As it ascends, it lies immediately to the right of the aorta, then overlaps the right lumbar sympathetic trunk and crosses the right renal artery. When the aorta passes beneath the median arcuate ligament of the diaphragm, the inferior vena cava continues upwards, lying on the right crus of the diaphragm, where the tip of the right suprarenal tucks behind it, to pass through the central tendon of the diaphragm at the level of T8 – a full four vertebral levels above the aortic orifice. From below upwards, the inferior vena cava relates anteriorly with the peritoneum of the posterior abdominal wall and the root of the mesentery, then the third part of the duodenum, the portal vein, head of the pancreas with the common bile duct, then the first part of the duodenum, then behind the posterior wall of the epiploic foramen (the foramen of Winslow) where it lies behind the portal triad of the hepatic artery, bile duct and portal vein. Above this it deeply grooves the posterior aspect of the bare
ANAESTHESIA AND INTENSIVE CARE MEDICINE 8:6
254
© 2007 Published by Elsevier Ltd.
Abdominal aorta, inferior vena cava and their branches
Aorta and inferior vena cava and the principal branches or tributaries Hepatic veins
Phrenic artery
Harold Ellis Coeliac axis
Left renal artery and vein
Superior mesenteric artery
Abstract The aorta enters the abdomen at T12 between the crura of the diaphragm and ends at L4 by dividing into the common iliac arteries, which in turn divide into the external and internal iliacs. The external gives no branches apart from just above its termination into the common femoral artery – the inferior epigastric and deep circumflex iliac. The internal iliac artery gives off numerous visceral and body wall branches to the pelvic organs, pelvic wall, perineum and buttock region. The aorta gives off visceral branches anteriorly (coeliac, superior and inferior epigastrics) and laterally (suprarenal, renal and gonadal – testicular and ovarian – as well as inferior phrenic, four lumbar and the middle sacral artery). The inferior vena cava commences by the junction of the common iliac veins in front of L5. It lies immediately to the right of the aorta but is considerably longer because it ascends to the right crus of the diaphragm to pierce the central tendon of the diaphragm at T8, having deeply grooved the posterior aspect of the liver at its bare area. The tributaries of the inferior vena cava differ from the branches of the aorta in two respects. First, those corresponding to the anterior visceral branches of the aorta form the portal vein, which passes into the liver at the porta hepatis. Venous blood then returns to the inferior vena cava via the right, middle, left and accessory hepatic veins. Second, the suprarenal and gonadal veins on the left side, unlike those on the right, which drain directly into the inferior vena cava, empty into the left renal vein, which then crosses the front of the aorta to enter the inferior vena cava.
Inferior mesenteric artery
Left testicular (or ovarian) artery and vein
Lumbar artery and vein Median sacral artery
Common Internal
Iliac artery and vein
External
Figure 1
the splenic vein, the left renal vein, the third part of the duo denum and, below this, the peritoneum of the posterior abdom inal wall and loops of small intestine. The aorta can be marked out by a line running in the midline from just above the transpyloric plane to the supracristal line, which joins the iliac crests. It can be palpated by firm midline pressure above the supracristal line and, indeed, seen to pulsate in thin patients. Branches of the aorta There are three anterior branches to the abdominal viscera: the coeliac axis (at the commencement of the abdominal aorta at T12) which divides into the hepatic, splenic and left gastric branches; the superior mesenteric artery at L1; and the inferior mesenteric artery at L3. Three branches to the viscera derive from the lateral sides of the aorta, close to each other at about the transpyloric plane: the right and left renal arteries; the suprarenal arteries just above the renal origins; and the gonadal arteries (ovarian or testicular) just below the renals. A series of branches supply muscles and soft tissues: the in ferior phrenic, running over the crus of the diaphragm on each side (an important supply to the diaphragm); the lumbar arteries (four on each side); and the median sacral artery, derived from the aortic bifurcation, a small vessel running over the front of the sacrum.
Keywords aorta; common, external and internal iliac vessels; hepatic veins; inferior vena cava; suprarenal and gonadal vessels
The abdominal aorta (Figure 1) The thoracic aorta passes through the diaphragm between its crura and beneath the median arcuate ligament immediately in front of the 12th thoracic vertebra. It passes downwards in front of the bodies of the lumbar vertebrae to end, very constantly, in front of the body of L4 to divide into the right and left common iliac arteries. It is crossed posteriorly by the left lumbar veins as they pass to the inferior vena cava, and these may be injured in mobilization of the aorta. To its right lies the inferior vena cava, to its left it overlaps the left lumbar sympathetic chain, and on either side lies the para-aortic chain of lymph nodes; importantly, these are the nodes of drainage of the testis and ovary. Anteriorly, the aorta lies behind, successively: the body of the pancreas with
The common iliac arteries These originate at the aortic bifurcation and pass along the medial edge of psoas, in close relationship to the vein, to end in front of the sacroiliac joint by bifurcating into the internal and external iliac. This is an important landmark for surgeons;
Harold Ellis, CBE, MCh, FRCS, was Professor of Surgery at Westminster Medical School until 1989. Since then he has taught anatomy, first at Cambridge and now at Guy’s Hospital, London.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 8:6
Left suprarenal artery and vein
253
© 2007 Published by Elsevier Ltd.
Vascular
very constantly the ureter crosses the external iliac artery at the bifurcation and then runs down on the anterior aspect of the internal iliac artery.
The hepatic and portal veins Right, middle and left hepatic veins draining into inferior vena cava
The external iliac artery continues on psoas along the pelvic brim to pass beneath the inguinal ligament to become the common femoral artery. Each is accompanied by its vein, but (fortunately for surgeons) remains superficial to the vein on either side (Figure 1). The external iliac artery gives off no branches until near its termination, when it gives rise to two vessels, which help supply the anterior abdominal wall – the inferior epigastric and the deep circumflex iliac arteries.
Portal vein
The internal iliac artery passes into the pelvis and soon divides into numerous branches in a variable manner. However, the branches themselves are constant, and are described below. The visceral branches supply the pelvic organs. In the male, the superior vesical artery supplies the bladder; the inferior ves ical the bladder base, prostate and seminal vesicles; and the middle rectal the rectum and upper anal canal. In the female, there is, in addition, the uterine artery, which passes transversely across to the uterus and crosses the ureter, and is therefore in danger of damage at this point. Also in the female, the inferior vesical artery is replaced by the vaginal artery, which passes the vagina and anastomoses with the uterine artery. The body wall branches supply the soft tissues lining the pelvis, perineum and buttock. These comprise the ilio-lumbar, lateral sacral, superior and inferior gluteal, obturator, and in ternal pudendal arteries.
Splenic vein Superior–inferior mesenteric veins Figure 2
area of the liver. Here it receives its largest tributaries: the three hepatic veins. The tributaries of the inferior vena cava The iliac veins run with their arteries, and the internal and external iliacs have tributaries that accompany their arterial branches. There are two important differences between the branches of the aorta and the tributaries of the inferior vena cava. First, obviously the veins which accompany the coeliac, and the superior and inferior mesenteric arteries are collected into the portal system of veins; the splenic vein and the superior mesenteric vein join behind the pancreas to form the portal vein, while the inferior mesenteric vein drains into the splenic vein. The portal blood, having passed through its hepatic capillaries, reunites with the hepatic venous system, which drains into the inferior vena cava via the large right, middle and left hepatic veins together with a variable number of accessory hepatic veins as the inferior vena cava lies in its deep groove on the posterior aspect of the liver (Figure 2). Second, although the lateral visceral veins on the right side (the suprarenal, renal and gonadal) drain directly into the inferior vena cava, the suprarenal and gonadal (ovarian or testicular) veins on the left side drain into the left renal vein, which has a long course as it passes across the anterior aspect of the aorta immediately inferior to the origin of the superior mesenteric artery (Figure 1). ◆
The inferior vena cava (Figure 1) This vein is considerably longer than the abdominal aorta. It commences inferiorly by the confluence of the common iliac veins behind the right common iliac artery in front of the body of L5. As it ascends, it lies immediately to the right of the aorta, then overlaps the right lumbar sympathetic trunk and crosses the right renal artery. When the aorta passes beneath the median arcuate ligament of the diaphragm, the inferior vena cava continues upwards, lying on the right crus of the diaphragm, where the tip of the right suprarenal tucks behind it, to pass through the central tendon of the diaphragm at the level of T8 – a full four vertebral levels above the aortic orifice. From below upwards, the inferior vena cava relates anteriorly with the peritoneum of the posterior abdominal wall and the root of the mesentery, then the third part of the duodenum, the portal vein, head of the pancreas with the common bile duct, then the first part of the duodenum, then behind the posterior wall of the epiploic foramen (the foramen of Winslow) where it lies behind the portal triad of the hepatic artery, bile duct and portal vein. Above this it deeply grooves the posterior aspect of the bare
ANAESTHESIA AND INTENSIVE CARE MEDICINE 8:6
254
© 2007 Published by Elsevier Ltd.