Retroperitoneum Flashcards
What are the two layers of the peritoneum?
Parietal and visceral layers
What is the peritoneum?
Serous membrane that forms the lining of the abdominal cavity and covers most of the abdominal organs
What are the two separate compartments of the peritoneal cavity?
Lesser sac and greater sac
Where is the lesser sac?
Between the liver, pancreas and stomach
Where is the entrance to the lesser sac?
Epiploic foramen
Where is the pouch of Douglas?
Peritoneal recess extending between the rectum and the uterus
List the intraperitoneal structures.
Stomach Jejunum 1st part of duodenum Appendix Spleen Cecum Transverse and sigmoid colon Rectum Liver Uterus Fallopian tubes Ovaries
Where is the retroperitoneum located?
Posteriorly between the transversalis fascia and the posterior parietal peritoneum
What divides the retroperitoneum coronally into three compartments?
Renal fascia (Gerota’s fascia)
What are the 3 compartments of the retroperitoneum?
Anterior pararenal space
Perirenal space
Posterior pararenal space
List the structures of the retroperitoneum.
Kidneys and ureters Adrenal glands Ascending and descending colon Second, third and fourth parts of the duodenum Pancreas Aorta and IVC Renal vessels Superior mesenteric vessels Gonadal vessels Lymphatics Prostate Rectum Esophagus
List the “abdominal sandwich”.
ANTERIOR Transversalis fascia Anterior parietal peritoneum Peritoneal space Anterior pararenal space Anterior renal fascia Perirenal space Posterior renal fascia Posterior pararenal space Transversalis fascia POSTERIOR
What two structures lie posterior to the posterior pararenal space and are separated by their own fascia?
Quadratus lumborum and psoas muscles
What is the first major branch of the abdominal aorta?
Celiac axis
What are the three branches of the celiac axis?
Common hepatic artery
Left gastric artery
Splenic artery
What two arteries make up the seagull or dove sign on ultrasound?
Common hepatic artery and the splenic artery
What is the 2nd branch off the abdominal aorta?
Superior mesenteric artery
What are the Doppler waveforms seen in the SMA?
Fasting state - high resistance
Postprandial - low resistance
Where do the renal arteries arise from on the aorta?
Just below the origin of the SMA
What is the most common tumor to involve the IVC?
Renal cell carcinoma
What are causes of IVC displacement?
Liver mass Right renal artery aneurysm Lymphadenopathy Tortuous aorta Right renal/adrenal mass
What is the proper location for an IVC filter?
Inferior to the renal veins
List the three hepatic veins.
Right, middle and left
Which renal vein is longer?
Left renal vein
What is the Nutcracker syndrome?
Engorgement of the left renal vein due to its compression by the SMA and aorta
Which gonadal vein drains directly into the IVC?
Right gonadal vein
The left gonadal vein drains into the left renal vein
What is Ormond’s disease?
Retroperitoneal fibrosis, inflammatory aneurysm
Dense fibrous tissue proliferation confined to the paravertebral region
What is associated with bilateral ureteral obstruction?
Retroperitoneal fibrosis because it envelopes structures rather than displacing them
Which veins provide an alternate pathway for venous return in the case of IVC obstruction?
Azygos and hemiazygos veins
What is unique about the azygos vein?
It is unpaired, the hemiazygos is a tributary of the azygos vein
Where does the ascending lumber vein join the right subcostal vein to form the azygos vein?
Level of the diaphragm
What is the difference between the right and left adrenal glands?
The right is shaped like a triangle or pyramid
The left is crescent shaped
Where is the crus of the diaphragm located?
Anterior to the aorta
Superior to the celiac axis
Posterior to the IVC
How does the adrenal cortex appear on ultrasound?
Hypoechoic and typically is less echogenic than the surrounding retroperitoneal fat
How does the adrenal medulla appear on ultrasound?
Echogenic linear structure within the adrenal gland
What three arteries supply each adrenal gland?
Suprarenal renal branch of the inferior phrenic artery
Suprarenal branch of the aorta
Suprarenal branch of the renal artery
What steroid hormones does the adrenal cortex produce?
Mineralcorticoids (Aldosterone)
Glucocorticoids (Cortisol)
Androgens
What regulates the adrenal cortical hormones?
Adrenocorticotropic hormones of the anterior pituitary gland
What two organs function together to regulate hormones production?
Adrenal gland and the anterior pituitary gland
What stimulates the adrenal cortex?
Increased ACTH from a decrease in adrenal cortical function
What leads to a drop in the activity of the adrenal cortex?
Increase in adrenal hormones that leads to a drop in ACTH secretions
Which catecholamines are produced by the adrenal medulla?
Epinephrine
Norepinephrine
What syndromes are the result of adrenal hyperfunctioning from adrenal adenomas?
Cushing’s syndrome
Conn syndrome
What is Cushing’s syndrome associated with?
Excessive cortisol secretion Administration of glucocorticoids
Increased ACTH from a pituitary adenoma
Primary adrenal adenoma
Ectopic ACTH
What is Conn syndrome associated with?
Excessive aldosterone secretion
Adrenal adenomas
Adrenal hyperplasia
What causes hirsutism?
Excessive androgen production from Congenital adrenal hyperplasia Pituitary tumor Adrenocortical carcinoma Ovarian tumor PCOS
How do patients with adrenal cortical carcinoma present?
Cushing’s syndrome
Metastatic involvement
What do adrenal cortical carcinomas have a tendency to invade?
Renal veins and IVC
Where do pheochromocytomas originate?
Adrenal medulla
May occur in ectopic locations
What do pheochromocytomas secrete?
Catecholamines (Norepinephrine and epinephrine)
What are pheochromocytomas associated with?
MEN
Von Hippel-Lindau disease
What is an adrenal neuroblastoma?
Malignant tumor arising from the sympathetic nervous system
What is the most common presentation of an adrenal neuroblastoma?
Palpable abdominal mass
What is the most common adrenal mass of infancy and early childhood?
Adrenal neuroblastoma
Between what ages do adrenal neuroblastomas occur?
Two months and two years
How do adrenal neuroblastomas appear on ultrasound?
Solid mass that displaces the ipsilateral kidney inferiorly into the pelvis
What is a myelolipoma?
Benign, nonfunctioning adrenal masses that contain fat and bone elements
What artifact is a myelolipoma associated with?
Propagation speed artifact
What is the most common cell type associated with adrenal lymphoma?
Non-Hodgkin’s disease
What is the fourth most common metastatic site?
Adrenal glands
At what age group is adrenal hemorrhage the most common?
Neonate
How does adrenal hemorrhage appear on ultrasound?
Variable due to blood coagulation
What is the most common adrenal mass in a newborn?
Adrenal hemorrhage
List the direction in which the IVC will be displaced? Right liver mass Right renal artery aneurysm Tortuous aorta Right adrenal mass Right renal mass
Posterior Anterior Right Medial/anterior Medial/left
How does lymphadenopathy displace the IVC and SMA?
Anteriorly
What direction will the splenic vein be displaced by a left adrenal mass?
Anterior
What direction will the bladder be displaced by hematoma in the pouch of Douglas?
Anterior
With a gastric outlet obstruction and dilatatian of the stomach, what direction will be pancreatic tail be displaced?
Posterior
What direction will a mass in the uncinate process displace the SMV?
Anterior
What direction will a neuroblastoma displace the ipsilateral kidney?
Inferior
What direction will a mass in the left lobe of the liver displace the gastroesophageal junction?
Posterior
