Anatomy - Gross Anatomy of the Retroperitoneum and Renal System

Abdominopelvic Cavity

Extension of abdominal cavity which houses and protects the male and female reproductive organs

Peritoneum

Lines the abdomino-pelvic cavity. Invest the viscera (e.g., stomach and other parts of the GI tract). Made up of two continuous layers: parietal and visceral peritoneum

Peritoneal Cavity

Space between the parietal and visceral peritoneum

Parietal Peritoneum

Lines the surface of the abdominopelvic wall. Same blood and nerve supply as the abdominal/body wall. Sensitive to pressure, pain, heat & cold, lacerations. Pain is well-localized

Visceral Peritoneum

Completely or almost completely covers the spleen and stomach. Invest viscera such as the stomach & intestines. Same blood and nerve supply with the viscera or organ that it covers. Insensitive to touch, heat & cold, lacerations. Stimulated primarily by stretching & chemical irritation

Visceral Peritoneum

If a patient is suffering from diarrhea, the pain that is felt by the patient is most likely coming from what part of the peritoneum?

Parietal Peritoneum

Pain caused by stab wounds or lacerations in the abdomen will mainly be localized. The pain that is felt by the patient is most likely coming from what part of the peritoneum?

Extraperitoneal

Structures found outside the peritoneum

Retroperitoneal

Location: behind the peritoneum. Organs are bounded by the parietal peritoneum anteriorly and posterior abdominal wall

Subperitoneal

Location: inferior to the peritoneum (e.g. urinary bladder)

True

There are NO organs inside the peritoneal cavity. True or False?

Retroperitoneum

An anatomical space in the abdominal cavity that is bounded anteriorly by the peritoneum and posteriorly by the posterior abdominal wall. Divided into spaces with the kidney as its reference point

Anterior Pararenal Space (APS)

Anterior boundary: parietal peritoneum. Posterior boundary: anterior portion of the renal fascia. Contains the pancreas, ascending and descending colon, duodenum

Perirenal Space (PS)

Space within the renal fascia. Anterior boundary: anterior renal fascia. Posterior boundary: posterior renal fascia. Contains the kidneys, renal vessels, ureter, perineal fat, adrenal glands

Posterior Pararenal Space (PPS)

Anterior boundary: posterior renal fascia. Posterior boundary: posterior abdominal wall. Mainly contains fats

Retro Mesenteric Plane (RMP) & Retro Renal Space (RRS)

Considered as potential spaces – not really appreciated anatomically in normal conditions. Become actual spaces in pathologic situations or conditions that may serve as pathways through which retroperitoneal lesions can spread beyond the original compartment by dissecting the fascia

Suprarenal Glands, Aorta, Duodenum, Pancreas, Ureter, Colon, Kidneys, Esophagus, Rectum

What are the retroperitoneal organs? (SADPUCKER)

Primary retroperitoneal organs

These include organs that are already located retroperitoneally from the beginning of their development

Secondary Retroperitoneal Organs

These include organs that are embryologically located intraperitoneally at the beginning of their development, but were pushed retroperitoneally as they developed

Pancreas Tail, Transverse & Sigmoid Colon, Duodenal Cap

What are the secondary retroperitoneal organs? (PCD)

Posterior Abdominal Wall

Posterior border of the retroperitoneum. Composed of different structures like bones, muscles, and blood vessels

Floating ribs 11 and 12, Lumbar Vertebra, Iliac Crest

What are the bone components of the posterior abdominal wall?

Diaphragm, Psoas major & minor, Quadratus lumborum, Iliacus

What are the muscle components of the posterior abdominal wall?

Aorta, Inferior Vena Cava

What are the blood vessels components of the posterior abdominal wall?

Lumbar Plexus

Composed of the anterior rami of L1 to L4. Will terminate immediately as branches

Iliohypogastric and Ilioinguinal Nerves

Supply the sensation of the hypogastric and inguinal area

Genitofemoral Nerve

Supply sensation of the anterior aspect of the thigh and part of the genital area. Specifically: scrotum in males, labia in females

Lateral Femoral Cutaneous Nerve

Provide sensory innervation to the lateral aspect of the thigh. Impingement of this nerve will result in meralgia paresthetica

Meralgia paresthetica

Impingement of the lateral cutaneous nerve will result in?

Obturator Nerve

Supply the adductor group of muscles

Femoral Nerve

Supply the hip flexors

Iliohypogastric Nerve

Segment: L1

Muscles Innervated: Transversus Abdominis, Internal oblique

Ilioinguinal Nerve

Segment: L1

Muscles Innervated: Transverse Abdominis, Internal oblique

Genitofemoral Nerve

Segment: L1-L2

Muscles Innervated: Cremaster (in males), Sensory distribution in upper thigh, spermatic cord and posterior scrotum, and inferior labia majora

Femoral Nerve

Segment: L2-L4

Muscles Innervated: Psoas, Rectus femoris, Vastus lateralis, Vastus medialis , Vastus intermedius, Sartorius, Iliacus

Lateral Femoral Cutaneous Nerve

Segment: L1-L3

No muscular innervation

Obturator Nerve

Segment: L2-L4

Muscles Innervated: Obturator internus, Adductor magnus, A. longus, A. brevis, Gracilis, Pectineus

Kidney

The main organ of retroperitoneum. Bean-shaped organs that lie retroperitoneally on the posterior abdominal wall. Located at the level of T12 - L3, with the right kidney slightly lower than the left because of the presence of the liver

Fibrous capsule

The external surface of the kidney is covered by a tough?

Anterior Surface

External Appearance of Kidney: Facing the Peritoneum

Posterior Surface

External Appearance of Kidney: Facing the Posterior Abdominal Wall

Medial Margin

External Appearance of Kidney: Concave, Serves as the area of entry and exit of the vascular structures via the hilum

Lateral Margin

External Appearance of Kidney: Convex

Superior Pole

External Appearance of Kidney: Accommodate the suprarenal glands. Still separated from the kidneys by a weak fascial septum. The primary attachment of the suprarenal gland is to the diaphragm

Inferior Pole

External Appearance of Kidney: In performing surgical procedures or examinations, this is just a finger breadth superior to the iliac crest, a palpable surface landmark

Perirenal (Perinephric) Fat

Surrounds the kidney

Gerota’s (Perirenal) Fascia

Condensed membranous layer enclosing the kidneys, suprarenal glands, and fats. Continuous laterally with the transversalis fascia

Anterior Renal Fascia

Blends with the fascia covering the great vessels

Posterior Renal (Zuckerkandl’s) Fascia

Blends with the fascia of the psoas muscle

Periureteric Fascia

Inferomedial continuation of the renal fascia that delicately covers the surrounding ureter

Renal Artery

Direct lateral branches of the abdominal aorta at the level of L1-L2 vertebra

Right Renal Artery

Renal Artery that is longer and lower

Left Renal Artery

Renal Artery that is shorter and higher

Five (4 anterior, 1 posterior)

How many segmental branches of the renal artery?

Brodel’s Line

A plane located in the posterolateral aspect of the kidney that is less vascular. During the surgical removal of a renal stone, an incision is made here to avoid bleeding.

Renal Vein

Emerges from the hilum and drains into IVC

Right Renal Vein

Renal Vein that is shorter and drains directly to IVC

Suprarenal Vein, Gonadal Vein, Ascending Lumbar Vein

What are the tributaries of the left renal vein? (SUPR GOLUM)

Nutcracker Syndrome

Involves the compression of the left renal vein, usually between the abdominal aorta and the superior mesenteric artery. This can increase pressure in the vein and its tributaries, causing dilatation.

Abdominal Aorta → Renal Arteries → Segmentar Arteries → Arcuate Artery → Cortical Radiate Arteries → Afferent Arterioles → Glomerular Capillaries → Efferent Arterioles

Trace the renal blood flow

Fibrous Capsule

Covers the entire kidney up to its sinus

Renal Cortex

Outer; outside part of the kidney. Covers the renal medulla

Renal Medulla

Inner; inside part of the kidney. Contains little triangular pieces called the renal pyramids

Renal Pyramid

Located in the area of the medulla. Tip or apex: pointing towards the sinus or the hilum. Base: facing the cortex

Renal Papilla

Tip of the renal pyramid where the urine empties into the minor calyx

Renal Columns of Bertin

Located between the renal pyramids

Renal Sinus

Cavity within the center of the kidney. Centrally located space. Lined continuously by the fibrous capsule. Occupied by the renal pelvis, blood vessels, and fat

Major Calyx

Formed by converging of 2 to 3 minor calyces

Renal Pelvis

Formed by converging of 2 to 3 major calyces. Will be called ureter as it exits the hilum of the kidney

Ureter

The urine collected in the renal pelvis will exit the kidneys via these Bilateral tubular organs. Approximately 25-30cm in length. 3-4mm in diameter

Ureteropelvic Junction

Located near the origin of the ureter. After exiting the renal hilum, the ureter will have a decrease in diameter as it chords downward

Pelvic Brim

As the ureter crosses this bony structure and the external iliac artery, there is a mechanical compression leading to a decrease in luminal space

Vesico-ureteric Junction

At the entrance of the bladder. The decrease in diameter is caused by the muscles of the bladder wall

Kidney Stones (Nephrolithiasis)

Patients will complain of pain in the flank/lumbar area. Stones may dislodge and obstruct the flow of urine

Ureterolithiasis

If the stones are located in the ureter, the condition will now be called?

T11-L2

The sensory supply of the ureter comes from?

Hypogastric below umbilicus (Lumbar Area)

Stone obstructed at the ureteropelvic junction: Pain is somewhere in

Loin up to groin area

Stone obstructed at the distal part of the ureter: Pain in the

Urinary Bladder

A hollow viscus characterized by its distensibility. Serves as a temporary reservoir of the urine with a normal capacity of 400 to 600mL. Located within the pelvic cavity and is considered a subperitoneal organ

Detrusor Muscle

The ureters will enter through the posterior aspect of the bladder through the _____________ in the trigone region

Body

The major part where the urine is collected

Neck

The funnel-shaped extension of the body that connects with the urethra

Trigone

A smooth triangular region inside the urinary bladder. Formed by the entry of the left and right ureters, and the proximal portion of the urethra near its neck

Segmental Artery

Supplies the apical portion of the kidney

L1-L2

The hilum of the kidney is found at the level of?