Anatomy of Kidney Flashcards
Where are the Kidneys situated?
Retro-peritoneally in the posterior abdominal wall by the side of the vertebral column.
What is the vertebral extent of the kidney?
T12 - L3
- Right kidney is 1.25 cm lower than the left kidney (being pushed downwards by the liver)
- Left kidney is longer and narrower, nearer to the vertebral column
- The upper pole of the right kidney reaches the 12th rib
- The upper pole of the left kidney reaches the 11th rib.
Features of the Two poles of the kidneys
Upper and Lower Pole
- The long axis of the kidney is parallel with the lateral border of the Psoas major muscle
- The upper pole is nearer to the midline than the lower pole.
Features of the Two borders of the kidneys
- Medial and Lateral border
- The lateral border is convex.
- The medial is concave and presents a hilum in its middle.
- Through the hilum, 3 structures enter or leave the kidney:
- Anterior to posterior: Renal vein, Renal artery, Ureter.
Posterior Relations of the Kidney
1) Four muscles:
- diaphragm (upper 1/3)
- Psoas major
- quadratus lumborum
- transversus abdominis (the lower 2/3 from medial to lateral)
2) Neuro-vascular structures:
- Subcostal nerve & vessels.
- Ilio- hypogastric nerve.
- Ilioinguinal nerve
3) Pleura and ribs:
The diaphragm separates the upper part of each kidney from the costo- diaphragmatic recess of the pleura and 12th rib on the right side and the 11th and 12 ribs on the left side.
- If there is a defect in the diaphragm, the kidney is in direct contact with the pleura and last rib.
- The pleura may be injured during surgical exposure of the kidney through the loin.
Anterior Relations of the Kidney
Right Kidney:
- Suprarenal glands
- Hepatic area
- Duodenal area
- Colic area
- Jejunal area
Left Kidney:
- Suprarenal glands
- Gastric area
- Splenic area
- Pancreatic area
- Colic area
- Jejunal area
Bare areas of the kidney
Bare areas on Rt. Kidney:
- Suprarenal area
- Duodenal area
- Colic area (hepatic flexure)
Bare areas on Lt. Kidney:
- Suprarenal area
- Pancreatic area
- Colic area (descending colon)
Fascia covering the kidney
1) Fibrous capsule: surrounds the kidney all around.
2) The perirenal fat surrounds the kidney all around and keeps the kidney in its site.
3) Renal fascia: it is formed of 2 layers which cover the front and back of the kidneys.
- It is continuous with:
Laterally: Fascia transversalis
Medially: Fascia around the renal vessels, aorta and IVC
Superiorly: Diaphragmatic fascia
Inferiorly: It remains loose
Blood Supply to the Kidney
- The renal arteries arise from the side of the abdominal aorta, opposite the upper border of the L2 vertebra.
- The right renal artery is longer than the left and passes posterior to I VC.
- Each renal artery divides into 5 segmental arteries—► interlobar arteries (run at the sides of the pyramid)—► arcuate arteries (run in the plane between the cortex and medulla) —► cortical radiate arteries (run towards the surface of the kidney)
- Both right and left renal veins open directly into IVC.
- Left renal vein is longer than the right & passes anterior to the aorta below origin of the superior mesenteric artery.
- The left vein receives the left suprarenal and left gonadal veins.
Lymphatic Drainage
Lumbar (aortic & caval) Lymph nodes.
Nerve Supply of the Kidney
Renal sympathetic plexus
- The afferent fibres that travel through the renal plexus & ascend the spinal cord through the lowest splanchnic nerve
- The afferent nerve fibres enter the spinal cord at the level of T12 segment.
Surface markings of the Kidney
The upper end: lies 1 inch from midline opposite upper end of T12 vertebra.
The hilum is 2 inches from midline; the hilum of the right kidney is just below and that of the left kidney just above (L1).
The lower end: is 3 inches from the midline opposite L3 vertebra.
