Anatomy of the kidney (1/7): renal artery, vein and nerves
Review literature: (Benninghoff, 1993).
Gross Anatomy of the Kidney
The kidneys are a paired organ; one kidney weighs 120–200 g. The normal kidney measures 10–12 cm vertically, 5–7 cm transversely and 3 cm a.p. The outer surface can be divided into anterior side, dorsal side, upper pole and lower pole. The lateral surface is convex. The medial surface is concave, deeply grooved (renal sinus
) and forms the renal hilum
. The ureter/renal pelvis, renal artery, renal vein, lymphatic vessels and nerves enter or exit through the renal hilum the kidney.
Fascias of the kidney
The kidneys have a tough organ capsule (Capsula fibrosa), which follows medially the renal parenchyma and does not surround the renal hilum. The kidneys are surrounded by a layer of perinephric fat (Capsula adiposa). The perinephric fat is surrounded by a connective tissue sheath, Gerota's fascia (Fascia renalis). Gerota's fascia surrounds the kidney, including perinephric fat and the adrenal gland. Cranially and laterally, the Gerota's fascia is closed by fusion of the anterior and posterior sheat. Medially and inferiorly, there is no connection between the anterior and posterior sheat of the Gerota's fascia: renal fluid collections can drain into the pelvis. The anterior sheat of the Gerota's fascia lies immediately below the parietal peritoneum [fig . renal and retroperitoneal fascias].
||fig. renal and retroperitoneal fascias: fascia transversalis (1), anterior sheat of the Gerota's fascia (2), parietal peritoneum (3), perinephric fat (Capsula adiposa) (4), paranephric fat (5), M. quadratus lumborum (6), M. erector spinae (7). Figure from Gray's Anatomy, Lea and Febinger 1918, Philadelphia, USA.
Topographic Anatomy of the kidneys
The kidneys are located in the retroperitoneum, right and left of the spine and below the diaphragm. Normal position:
- Left kidney: from the 11th rib to third lumbar vertebra.
- Right kidney: slightly lower position, 12th rib to the lower part of the third lumbar vertebra.
Topographic Anatomy of the Right Kidney
- Dorsally: 12th rib, subcostal nerve, iliohypogastric nerve, ilioinguinal nerve, quadratus lumborum muscle, diaphragm with pleura at the upper pole
- Cranially: adrenal gland.
- Medially: psoas major muscle, inferior vena cava, ovarian/testicular vein, ureter.
- Ventrally: liver, duodenum, ascending colon.
Topographic Anatomy of the Left Kidney
- Dorsally: 11th and 12th rib, subcostal nerve, iliohypogastric nerve, ilioinguinal nerve, quadratus lumborum muscle, diaphragm with pleura at the upper pole
- Cranially: adrenal gland, spleen.
- Medially: psoas major muscle, aorta, ovarian/testicular vein, ureter.
- Ventrally: spleen, pancreas, stomach, descending colon.
Internal Anatomy of the Kidneys
The renal parenchyma has two distinct components: the renal cortex and the renal medulla. Since the form of the renal medulla is of pyramid shape, it is also called renal pyramids. In longitudinal section, the individual functional units of the kidney can be seen [fig. internal anatomy of the kidney]. The kidney consists of 7–9 renal lobes. Each lobe has a renal pyramid and is surrounding by cortex. Each lobe drains with its collecting tubules to an own renal calix, the collecting tubules indent the calix and form the renal papilla. Each kidney has 7–9 calices. The cortex-like parenchyma in between the renal pyramids is called renal columns of Bertin (Columnae renales).
The human kidney is principally a blend of about 14 single kidneys. In other species, the morphological separation of the single kidneys is more clearly visible (renculation). As a morphological variant, renculation is seen as Ren lobatus in some men, too.
The urine drains from the calix via the renal pelvis into the ureter.
||fig. internal anatomy of the kidney: renal pyramids (renal medulla) (1), renal cortex (2), minor calices (3), renal papilla (4), major calix (5), Sinus (6), Columns of Bertin (7), neck of calix (8), renal pelvis (9), ureter (10). Fig. from Gray’s Anatomy, Lea and Febinger 1918, Philadelphia, USA.
Vascular Supply of the Kidney: Renal Artery, Vein and Nerves
The kidneys are supplied by parietal branches of the aorta (renal artery). The vascular supply (A. renalis dexter et sinistra) is often subject to variations. The right renal artery passes under the vena cava to the right kidney. Both renal arteries run together with the renal veins.
The renal veins drain into the vena cava inferior. The left renal vein is longer and passes over the aorta below the superior mesenteric artery into the vena cava.
Lymphatic Vessels of the Kidney
The left kidney drains into the paraaortic lymph nodes. The right kidney drains into the paracaval and interaortocaval lymph nodes. The cranial and caudal extent of the renal lymph nodes along the vena cava and aorta ranges from the inferior mesenteric artery to the diaphragm.
Innervation of the kidney
The renal plexus is located around the renal artery and contains postganglionic fibers from the sympathetic nervous system (Th10 to L2). The nerve fibers from the plexus enter the kidney with the branches of the renal artery and regulate the vascular tone and the secretion of renin.
The renal function is not dependent of the above mentioned innervation, as shown with the renal function after renal transplantation (complete transsection of the innervation). Most of the renal functions are regulated by hormones.
Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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Benninghoff 1993 BENNINGHOFF, A.:
- Makroskopische Anatomie, Embryologie und Histologie des
München; Wien; Baltimore : Urban und Schwarzenberg, 1993