Retroperitoneum Flashcards
Peritoneum
- 2 layers
- ligaments & folds
2 layers of the peritoneum
- parietal = external
- visceral = internal (touching tissue)
Function of ligaments & folds in peritoneum
- creates a “cavity”
- support organs
- contains spaces/sacs
Retroperitoneum
area (space) btwn. posterior parietal peritoneum & posterior abdominal wall (retrofascia)
Borders of retroperitoneum
- diaphragm (pelvic floor)
- spine/ribs
- musculature
- parietal peritoneum (posteriorly)
Spaces in retroperitoneum
- anterior pararenal
- perirenal
- posterior pararenal
- subphrenic
Anterior pararenal space
- btwn. parietal peritoneum and kidney (majority in this space)
- duodenum/colon/pancreas
Perirenal space
- surrounding kidneys (Gerota’s fascia)
- adrenal gland/kidney/proximal ureter/great vessels
Posterior pararenal space
- btwn. kidney & posterior abdominal wall
- muscles (psoas/quadratus lumborum)
- spine is also behind it
Subphrenic space
btwn. liver or spleen & diaphragm
Other structures of retroperitoneum
- diaphragmatic crura (crus)
- lymph nodes
Diaphragmatic crura (crus)
- connections of the diaphragm to the spine, cross aorta & IVC
- right is longer & larger - posterior to IVC
Lymph nodes
- bean-shaped organs that collect lymphoid tissue (immunity/vascular filtration)
- found along aorta & its branches
Adrenal glands
- endocrine function
- paired
- Rt = triangular/pyramid shape
- Lt = crescent shaped
- blood supplied by multiple “suprarenal” arteries
Adrenal gland location/anatomy
- sit next to kidney w/in Gerota’s fascia
- larger at fetus & pediatric stages
- smaller as adults
- don’t mistake them for the kidneys
What does the cortex produce?
steroid & hormones
What does the medulla produce?
fight or flight response
What does the hypothalamus control?
hormone production
What does the anterior pituitary gland secrete?
adrenocorticotropic hormone
3 zones of the cortex
- zona glomerulosa
- zona fasciculata
- zona reticularis
What hormones are produced in the medulla?
epinephrine & norepinephrine
Epinephrine
- increases HR, BP, & blood flow
- opens airways in lungs
- narrows blood vessels in skin & intestines
Norepinephrine
- increases HR & BP
- contracts blood vessels
What is the vascular supply to the adrenal glands?
- lots of small vessels
- not a main system
Landmark for finding adrenal glands
kidneys
Scanning adrenal glands: adult
- medium-level echoes on superior & medial aspect of kidneys
Scanning adrenal glands: neonate
- hypoechoic rim seen around an echogenic core (hypertrophied cortex)
- proportionately larger in newborns
Lymph nodes sonographic anatomy
- less than or equal to 1cm
- not usually seen unless abnormal
- look for displacement of great vessels
Fluid collections/tumors sonographic anatomy
- evaluate clinical hx
- anechoic/hypoechoic/hyperechoic area
Ascites sonographic anatomy
- abnormal accumulation of serious fluid
- M/C cause is cirrhosis
- transudative
- exudative
Sarcoma
- retroperitoneal tumors
- bad
- found on all types of tissue
Pitfalls to imaging retroperitoneum
- bowel gas
- small size
medial/posterior location
adjacent anatomy has similar appearance to small structures
Landmarks of retroperitoneum location
- kidneys
- aorta/IVC
- spine
(posterior location)
What type of scan is the primary choice for imaging retroperitoneum?
- CT/MRI is more valuable
- U/S is more for a follow up
Scanning retroperitoneum for fluid-type collection
- hematoma
- urinoma
- ascites
