Renal Anatomy Module Tutorial

Renal Anatomy Module Tutorial (Answers)

• Students will learn about the kidneys' vulnerability to penetrating injury, the clinical significance of urinary calculi, referred renal/ureteric pain, and how ureter entry into the bladder prevents reflux.
• Students will also study the consequences of a ruptured abdominal aortic aneurysm, venous spread of cancer from the gut compared to paired viscera, and the lymph drainage of the kidneys.

Activity 1: Renal Trauma

• The kidneys lie behind the lower ribs, lumbar muscles, and vertebral column.
• The most vulnerable parts of the kidneys to penetrating injury are the anterior and superior surfaces.
• Penetrating injuries often involve other organs.

Kidney Trauma

• The kidneys are well-protected by the lower ribs, lumbar muscles, and vertebral column.
• A severe blunt abdominal injury can crush the kidney against the rib cage or vertebral column, causing varying degrees of damage, from bruising to laceration.
• Penetrating injuries, such as stab or gunshot wounds, often involve other abdominal organs.
• The kidneys receive a significant portion of cardiac output, thus, a renal injury can cause rapid blood loss.
• Anterior stab wounds may damage the renal pelvis or vascular pedicle, while posterior wounds primarily injure the renal parenchyma.
• Renal injuries are segmented; thus, injuries to the segmental vessels can have different consequences compared to blunt injuries, which tend to fracture between segments.
• Understanding the structure and arrangement of the renal segments is important for management.

Activity 2: Course and Constrictions of the Ureter

• The ureter runs downward, in front of the lumbar transverse processes, across the sacroiliac joint, then turns medially toward the bladder.
• The ureter has three constrictions: the junction of the renal pelvis and ureter; the area crossing the pelvic brim; and the point where the ureter pierces the bladder wall.
• Small stones often cannot be seen on plain X-rays, an IVP (Intravenous Pyelogram) is typically necessary to display the ureter.

Activity 3: Nerve Supply of Kidneys and Ureters

• The nerves supplying the kidneys come from the renal plexus.
• Afferent (pain) nerve fibers from the renal plexus travel to the T10-T12 thoracic spinal cord segments.
• The ureter receives innervation from the renal, testicular (or ovarian), and hypogastric plexuses.
• Visceral afferent fibers from the ureter return to the T11 to L2 spinal cord segments.

Q2: Clinical Case with Renal Calculus

• A 50-year-old woman experienced severe, wave-like pain radiating from her right loin to the groin and thigh.
• An X-ray revealed a calculus in her right ureter.
• Possible locations where kidney stones can become lodged: renal pelvis/ureter junction, pelvic brim, and ureter entering the bladder.
• Kidney stones lodge in areas with anatomical narrowing.
• The pain is from peristaltic waves of ureter muscle contraction.
• The pain is referred to the related areas to the spinal segments supplying the related visceral nerves, explaining the extensive area pain.

Activity 4: Mechanism of Prevention of Urine Reflux

• The ureters' oblique entry into the bladder wall forms a one-way "flap valve."
• During micturition (urination), the contracting bladder creates a sphincter action, preventing urine reflux.

Activity 5: Abdominal Aorta & Aortic Aneurysm

• The abdominal aorta starts behind the diaphragm and extends to the level of the fourth lumbar vertebra where it divides into the common iliac arteries.
• The aorta's anterior relations include the stomach, celiac plexus, pancreas, colon, and peritoneum.
• The right side relations include the inferior vena cava, cisterna chyli, and azygos vein.
• The left side relation is the left sympathetic trunk.

Aortic Aneurysms

• An aneurysm is a localized or extensive dilation of the abdominal aorta, usually below the renal artery.
• Most frequently, aneurysms are caused by atherosclerosis.
• Rupture can cause serious consequences.
• Treatment for larger aneurysms often involves surgical replacement.

Activity 6: Venous Spread of Cancer

• Cancer originating from unpaired viscera (e.g., colon) usually spreads through the portal vein, potentially metastasizing to the liver.
• Cancer originating from paired viscera (e.g., kidneys) spreads via the inferior vena cava and commonly metastasizes to the lungs.
• The venous spread of cancer is significant since it can lead to metastasis.

Activity 7: Clinical Significance of Lymphatic Drainage of the Kidney

• Kidneys' lymphatic drainage: travels directly to para-aortic lymph nodes, lumbar lymph trunks, cisterna chyli, and later into the thoracic duct.

This quiz covers essential topics in renal anatomy, including kidney vulnerabilities to injury, urinary calculi, referred pain, and the importance of ureter entry into the bladder. Additionally, it discusses the implications of abdominal aortic aneurysms and cancer spread, as well as lymph drainage of the kidneys.