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The Anatomy of the Kidney and Ureter
HAEMOLYMPHOID SYSTEM
The anterior relations of the kidneys
The Anatomy of the Kidney and Ureter
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Harold Ellis
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The kidneys are situated behind the peritoneum of the posterior abdominal wall, largely under cover of the costal margin. The right kidney lies lower than the left, pushed down by the liver. In the great majority of normal subjects, the kidneys cannot be palpated but, in a particularly thin person, the lower pole of the right kidney may be just tipped on deep inspiration. As the kidneys lie in the paravertebral gutter, the renal hilum faces forwards as well as medially, while its long axis runs obliquely, parallel to the lateral border of psoas major. ������������ �����������������
Relations On each side, the suprarenal gland sits like a cap on the superior pole of the kidney. Anteriorly on the left lie the pancreas and its vessels, the spleen, the descending colon and the stomach; the last separated by the lesser sac, with the lieno-renal ligament passing to the splenic hilum near the lateral margin of the kidney. On the right lie the second part of the duodenum (at risk of injury in performing a right nephrectomy) the liver and the ascending colon (Figure 1). Posteriorly, both kidneys lie on the diaphragm and quadratus lumborum, overlapping the psoas medially and transversus abdominis laterally. The twelfth rib defines the position of the upper pole, anterior to which is the lowermost recess of the pleura, which may be opened in the course of the loin approach to the kidney. Three nerves lie posteriorly: the subcostal, ilio-hypogastric and ilio-inguinal (Figure 2). The hilum is the deep vertical slit on the medial border. This transmits, from before backwards, the renal vein, renal artery, the pelvis of the ureter and, usually, a posterior arterial branch. In addition, the hilum transmits lymphatics and autonomic nerve fibres, principally sympathetics from spinal segments T12 to L1. Sympathetic afferents account for the classical referral of renal pain to the lower abdominal wall and to the external genitalia. Within the renal substance, the pelvis of the ureter divides into two or three major calyces, each then dividing into several minor calyces. Each of these is indented by a papilla, on which the renal collecting tubules discharge urine. The calyceal system is readily appreciated on inspecting a normal intravenous urogram.
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The posterior relations of the kidney ��������� ����������� ������������������
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Harold Ellis is Emeritus Professor of Surgery, University of London (Charing Cross and Westminster Medical School), London, UK. He is currently Clinical Anatomist in the Division of Anatomy at King's College, London, at the Guy's Campus, London, UK. 2 SURGERY
201
© 2002 The Medicine Publishing Company Ltd
HAEMOLYMPHOID SYSTEM
The kidney possesses three capsules or fascial layers: • The true capsule: a glistening lucent sheet, which strips readily from the healthy organ, but which firmly adheres to the chronically inflamed kidney. • The perinephric fat: an abundant fatty cushion that fills the paravertebral gutter above the iliac crest. It may play a part in maintaining the position of the kidney, which certainly becomes more mobile when the fat is depleted in severe weight loss. • The renal fascia: this encloses the perinephric fat, passes to the inferior aspect of the diaphragm, lines the posterior abdominal wall behind the kidney, lies in front behind the parietal peritoneum, densely adheres to the renal vessels and pelvis at the hilum and, although thin, is complete below to enclose the kidney (Figure 3). This fascial sheath is of clinical interest; first, the suprarenal gland lies outside this layer in its own fascial compartment. When the kidney is mobilized in nephrectomy, the suprarenal usually remains safely in place (unless adherent from severe inflammatory scarring or neoplastic invasion). Second, a perirenal collection of fluid (blood or pus) will not track across to the other side because of the dense adherence of the fascia at the hilum. However, the collection may burst through the weak fascia inferiorly and track retro-peritoneally towards the pelvis.
on the left it crosses the aorta en route. The lymphatics of the kidney accompany the blood vessels and pass to the para-aortic nodes.
The ureter The ureter is 10 inches (25 cm) long. It comprises a pelvis and an abdominal, pelvic and intra-vesical portion. It is narrowed at three sites: the pelvi-ureteric junction, as it crosses into the pelvis, and at its termination. Obviously these are where a calculus is most likely to become lodged. The ureter descends on the medial edge of psoas major, which separates it from the transverse processes of L2–L5, and is crossed by the gonadal vessels; it is at risk when these are ligated and divided in gynaecological surgery. On the right, the ureter passes behind the third part of the duodenum before it emerges immediately deep to, and adherent to, the peritoneum of the posterior abdominal wall. On the left it passes behind the apex of the sigmoid mesocolon. It passes into the pelvis very constantly at the bifurcation of the common iliac artery, even when this vessel becomes tortuous and distorted in arteriosclerosis. The pelvic ureter runs on the pelvic lateral wall in front of the internal iliac artery, then turns forward and medially in front of the ischial spine to enter the bladder. In the male it lies above the seminal vesicle near its termination and is crossed superficially by only one structure: the vas deferens. In the female, it passes below the broad ligament and uterine vessels, (where it may be damaged at hysterectomy), and here passes above the lateral fornix of the vagina 0.5 inches (12 mm) lateral to the supravaginal portion of the cervix. Once in my life I palpated a large ureteric stone impacted at this site on pelvic examination! The intravesical part of the ureter passes obliquely through the bladder wall for 2 cm. The obliquity of this course and the involuntary muscles of the bladder wall produce respectively a valve-like and a sphincteric arrangement of the ureteric termination.
Blood supply and segmental anatomy (Figure 1) The wide-bored renal artery leaves the aorta at right angles on each side and lies behind the pancreas. At the hilum, typically, each artery divides into an anterior and posterior branch. The posterior supplies a posterior segment of the kidney, while the anterior gives rise to apical, upper, middle and inferior segmental branches. Although there are great variations in the exact method of branching of the main artery, the five segments of the kidney are constant, with no collateral circulation between them, so that segmental partial nephrectomy can be performed. The renal vein lies in front of the artery and passes directly to the inferior vena cava; on the right it has a short course,
Transverse section of the kidney: relationships of muscle and fascia ��������������� ���������� ��������������� ������������� ������ ����� ������������� ����������������
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SURGERY
202
© 2002 The Medicine Publishing Company Ltd
HAEMOLYMPHOID SYSTEM
Clinical anatomy
Disorders of Thrombosis and Haemostasis
Drawing from an intravenous pyelogram to show the relationship of the ureters to the bony landmarks
M J Nash Hannah Cohen
The surgical patient with a bleeding or thrombotic disorder presents a clinical challenge. The key to optimal management is early recognition of patients at risk coupled with close and effective liaison between the surgeon and haematologist. This article provides an overview of bleeding and thrombotic disorders with particular reference to surgical patients. Normal haemostasis Three physiological components act in concert to achieve haemostasis in vivo, namely the coagulation mechanism, platelets and the blood vessel wall. A physiological balance exists between pro- and anticoagulant mechanisms. Natural anticoagulants include heparan sulphate on endothelial cells, antithrombin and protein C and protein S. The process is completed by the dissolution of thrombi via the process of fibrinolysis, which enables repair of the damaged vascular endothelium.
4
To identify the ureter at laparotomy, it is conveniently discovered at the bifurcation of the common iliac artery. Its thick muscular wall, which vermiculates when gently squeezed with non-toothed forceps, and the fact that it adheres to the overlying peritoneum like a fly stuck on fly-paper, are diagnostic.
Coagulation mechanism (Figure 1) The coagulation system is a finely balanced network of interacting procoagulant and anticoagulant factors. The modern view of the events involved in this process differs from the ‘extrinsic’ and ‘intrinsic’ pathways, which were traditionally discussed. The first event in the coagulation mechanism is the binding of circulating factor VII to tissue factor (TF) exposed at a site of vascular injury. The VIIa.TF complex activates factors X and IX. Factor IXa activates factor X in the presence of factor VIIIa and calcium. Factor Xa then converts prothrombin to thrombin in the presence of factor Va and calcium. Thrombin then converts fibrinogen to fibrin, which is then stabilized by cross-linking catalyzed by factor XIII.
Blood supply The ureter receives a rich segmental and anastomosing blood supply from all the available vessels along its course, i.e. the renal, gonadal, internal iliac and vesical vessels. Only extensive stripping will devascularise it. In searching for a radio-opaque ureteric stone on a radiograph, imagine the course of the ureter in relation to the bony skeleton; along the tips of the transverse processes, crosses the front of the sacro-iliac joint, swings out laterally to the ischial spine, then passes medially to the bladder (Figure 4). u
M J Nash is a Specialist Registrar on the North Thames Haematology rotation, London, UK, and is currently undertaking research into the modulation of cellular fibrinolysis by antiphospholipid antibodies. He qualified in 1995 from St Mary's Hospital Medical School, London, UK. Hannah Cohen is Consultant Haematologist at University College London Hospitals NHS Trust, London, UK. She qualified from the University of Manchester Medical School, UK, and trained in haematology at University College London Hospitals. Her research interests include the pathophysiology and management of antiphospholipid syndrome and the role of thrombophilias in pregnancy loss.
FURTHER READING Cross J, Dixon A K. The renal tract and retroperitoneum. In: Butler P, Mitchell A, Ellis H, Eds. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999.
SURGERY
203
© 2002 The Medicine Publishing Company Ltd
The anterior relations of the kidneys
The Anatomy of the Kidney and Ureter
���������������������������� ������
Harold Ellis
������� �������� �����
The kidneys are situated behind the peritoneum of the posterior abdominal wall, largely under cover of the costal margin. The right kidney lies lower than the left, pushed down by the liver. In the great majority of normal subjects, the kidneys cannot be palpated but, in a particularly thin person, the lower pole of the right kidney may be just tipped on deep inspiration. As the kidneys lie in the paravertebral gutter, the renal hilum faces forwards as well as medially, while its long axis runs obliquely, parallel to the lateral border of psoas major. ������������ �����������������
Relations On each side, the suprarenal gland sits like a cap on the superior pole of the kidney. Anteriorly on the left lie the pancreas and its vessels, the spleen, the descending colon and the stomach; the last separated by the lesser sac, with the lieno-renal ligament passing to the splenic hilum near the lateral margin of the kidney. On the right lie the second part of the duodenum (at risk of injury in performing a right nephrectomy) the liver and the ascending colon (Figure 1). Posteriorly, both kidneys lie on the diaphragm and quadratus lumborum, overlapping the psoas medially and transversus abdominis laterally. The twelfth rib defines the position of the upper pole, anterior to which is the lowermost recess of the pleura, which may be opened in the course of the loin approach to the kidney. Three nerves lie posteriorly: the subcostal, ilio-hypogastric and ilio-inguinal (Figure 2). The hilum is the deep vertical slit on the medial border. This transmits, from before backwards, the renal vein, renal artery, the pelvis of the ureter and, usually, a posterior arterial branch. In addition, the hilum transmits lymphatics and autonomic nerve fibres, principally sympathetics from spinal segments T12 to L1. Sympathetic afferents account for the classical referral of renal pain to the lower abdominal wall and to the external genitalia. Within the renal substance, the pelvis of the ureter divides into two or three major calyces, each then dividing into several minor calyces. Each of these is indented by a papilla, on which the renal collecting tubules discharge urine. The calyceal system is readily appreciated on inspecting a normal intravenous urogram.
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1
The posterior relations of the kidney ��������� ����������� ������������������
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Harold Ellis is Emeritus Professor of Surgery, University of London (Charing Cross and Westminster Medical School), London, UK. He is currently Clinical Anatomist in the Division of Anatomy at King's College, London, at the Guy's Campus, London, UK. 2 SURGERY
201
© 2002 The Medicine Publishing Company Ltd
HAEMOLYMPHOID SYSTEM
The kidney possesses three capsules or fascial layers: • The true capsule: a glistening lucent sheet, which strips readily from the healthy organ, but which firmly adheres to the chronically inflamed kidney. • The perinephric fat: an abundant fatty cushion that fills the paravertebral gutter above the iliac crest. It may play a part in maintaining the position of the kidney, which certainly becomes more mobile when the fat is depleted in severe weight loss. • The renal fascia: this encloses the perinephric fat, passes to the inferior aspect of the diaphragm, lines the posterior abdominal wall behind the kidney, lies in front behind the parietal peritoneum, densely adheres to the renal vessels and pelvis at the hilum and, although thin, is complete below to enclose the kidney (Figure 3). This fascial sheath is of clinical interest; first, the suprarenal gland lies outside this layer in its own fascial compartment. When the kidney is mobilized in nephrectomy, the suprarenal usually remains safely in place (unless adherent from severe inflammatory scarring or neoplastic invasion). Second, a perirenal collection of fluid (blood or pus) will not track across to the other side because of the dense adherence of the fascia at the hilum. However, the collection may burst through the weak fascia inferiorly and track retro-peritoneally towards the pelvis.
on the left it crosses the aorta en route. The lymphatics of the kidney accompany the blood vessels and pass to the para-aortic nodes.
The ureter The ureter is 10 inches (25 cm) long. It comprises a pelvis and an abdominal, pelvic and intra-vesical portion. It is narrowed at three sites: the pelvi-ureteric junction, as it crosses into the pelvis, and at its termination. Obviously these are where a calculus is most likely to become lodged. The ureter descends on the medial edge of psoas major, which separates it from the transverse processes of L2–L5, and is crossed by the gonadal vessels; it is at risk when these are ligated and divided in gynaecological surgery. On the right, the ureter passes behind the third part of the duodenum before it emerges immediately deep to, and adherent to, the peritoneum of the posterior abdominal wall. On the left it passes behind the apex of the sigmoid mesocolon. It passes into the pelvis very constantly at the bifurcation of the common iliac artery, even when this vessel becomes tortuous and distorted in arteriosclerosis. The pelvic ureter runs on the pelvic lateral wall in front of the internal iliac artery, then turns forward and medially in front of the ischial spine to enter the bladder. In the male it lies above the seminal vesicle near its termination and is crossed superficially by only one structure: the vas deferens. In the female, it passes below the broad ligament and uterine vessels, (where it may be damaged at hysterectomy), and here passes above the lateral fornix of the vagina 0.5 inches (12 mm) lateral to the supravaginal portion of the cervix. Once in my life I palpated a large ureteric stone impacted at this site on pelvic examination! The intravesical part of the ureter passes obliquely through the bladder wall for 2 cm. The obliquity of this course and the involuntary muscles of the bladder wall produce respectively a valve-like and a sphincteric arrangement of the ureteric termination.
Blood supply and segmental anatomy (Figure 1) The wide-bored renal artery leaves the aorta at right angles on each side and lies behind the pancreas. At the hilum, typically, each artery divides into an anterior and posterior branch. The posterior supplies a posterior segment of the kidney, while the anterior gives rise to apical, upper, middle and inferior segmental branches. Although there are great variations in the exact method of branching of the main artery, the five segments of the kidney are constant, with no collateral circulation between them, so that segmental partial nephrectomy can be performed. The renal vein lies in front of the artery and passes directly to the inferior vena cava; on the right it has a short course,
Transverse section of the kidney: relationships of muscle and fascia ��������������� ���������� ��������������� ������������� ������ ����� ������������� ����������������
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������������ ����������������� 3
SURGERY
202
© 2002 The Medicine Publishing Company Ltd
HAEMOLYMPHOID SYSTEM
Clinical anatomy
Disorders of Thrombosis and Haemostasis
Drawing from an intravenous pyelogram to show the relationship of the ureters to the bony landmarks
M J Nash Hannah Cohen
The surgical patient with a bleeding or thrombotic disorder presents a clinical challenge. The key to optimal management is early recognition of patients at risk coupled with close and effective liaison between the surgeon and haematologist. This article provides an overview of bleeding and thrombotic disorders with particular reference to surgical patients. Normal haemostasis Three physiological components act in concert to achieve haemostasis in vivo, namely the coagulation mechanism, platelets and the blood vessel wall. A physiological balance exists between pro- and anticoagulant mechanisms. Natural anticoagulants include heparan sulphate on endothelial cells, antithrombin and protein C and protein S. The process is completed by the dissolution of thrombi via the process of fibrinolysis, which enables repair of the damaged vascular endothelium.
4
To identify the ureter at laparotomy, it is conveniently discovered at the bifurcation of the common iliac artery. Its thick muscular wall, which vermiculates when gently squeezed with non-toothed forceps, and the fact that it adheres to the overlying peritoneum like a fly stuck on fly-paper, are diagnostic.
Coagulation mechanism (Figure 1) The coagulation system is a finely balanced network of interacting procoagulant and anticoagulant factors. The modern view of the events involved in this process differs from the ‘extrinsic’ and ‘intrinsic’ pathways, which were traditionally discussed. The first event in the coagulation mechanism is the binding of circulating factor VII to tissue factor (TF) exposed at a site of vascular injury. The VIIa.TF complex activates factors X and IX. Factor IXa activates factor X in the presence of factor VIIIa and calcium. Factor Xa then converts prothrombin to thrombin in the presence of factor Va and calcium. Thrombin then converts fibrinogen to fibrin, which is then stabilized by cross-linking catalyzed by factor XIII.
Blood supply The ureter receives a rich segmental and anastomosing blood supply from all the available vessels along its course, i.e. the renal, gonadal, internal iliac and vesical vessels. Only extensive stripping will devascularise it. In searching for a radio-opaque ureteric stone on a radiograph, imagine the course of the ureter in relation to the bony skeleton; along the tips of the transverse processes, crosses the front of the sacro-iliac joint, swings out laterally to the ischial spine, then passes medially to the bladder (Figure 4). u
M J Nash is a Specialist Registrar on the North Thames Haematology rotation, London, UK, and is currently undertaking research into the modulation of cellular fibrinolysis by antiphospholipid antibodies. He qualified in 1995 from St Mary's Hospital Medical School, London, UK. Hannah Cohen is Consultant Haematologist at University College London Hospitals NHS Trust, London, UK. She qualified from the University of Manchester Medical School, UK, and trained in haematology at University College London Hospitals. Her research interests include the pathophysiology and management of antiphospholipid syndrome and the role of thrombophilias in pregnancy loss.
FURTHER READING Cross J, Dixon A K. The renal tract and retroperitoneum. In: Butler P, Mitchell A, Ellis H, Eds. Applied Radiological Anatomy. Cambridge: Cambridge University Press, 1999.
SURGERY
203
© 2002 The Medicine Publishing Company Ltd