Abdomen Comp Flashcards
Muscles of the abdomen?
- Diaphragm
- Psoas Muscles
What does the diaphragm do?
- separates abdominal cavity from thoracic cavity
- primary muscle of inspiration
Where are the psoas muscles located (vertebral level?)
-L1 to lesser trochanters
Parts of the digestive system?
- oral cavity
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
What is the first organ of the digestive system located in the abdominal cavity?
Stomach
3 parts of the small intestine?
- Duodenum
- Jejunum
- Ileum
What ligament is at the duodenojejunal junction?
Ligament of trietz
What increases surface area in the jejunum?
Plicae circularis
Where is the appendix attached to the colon?
Posteromedial colon
What is the sphincter at the terminal opening of the large intestine called?
Anus
How does the spleen sit in relation to the stomach?
Posterior and left
Can the spleen be seen on plain radiographs?
Faintly, especially if enlarged
Accessory digestive organs?
- pancreas
- liver
- gallbladder
- salivary glands
Can the pancreas be seen on plain radiographs?
No
Where is the spleen located?
- posterior to the stomach
- between the duodenum and spleen
- head in C-loop of duodenum “romance of abdomen”
- body and tail extend to upper left abdomen
What is the largest solid organ in the body?
Liver
What percent of gallstones have enough calcium to be visualized?
10-15%
Parts of the urinary system?
- 2 kidneys
- 2 ureters
- bladder
- urethra
Vertebral level of kidneys?
T11-L3
3 constriction points of ureters?
- ureteropelvic junction
- pelvis brim
- ureterovesical junction
Where do the ureters enter the bladder?
Posterolateral aspect
Can kidneys been seen on plain radiographs? Why/why not?
Yes, because they have a fatty capsule that surrounds them
How do the kidneys sit in the body?
20 degrees medial (superior more medial)
30 degrees anterior (inferior more anterior)
What is the peritoneum? Parts?
- serous, double walled membrane
- parietal: adheres to cavity
- visceral: portion that covers organs
- contains serous fluid
- mesentery, omentum (greater/lesser), mesocolon
The visceral peritoneum only partially covers what organs?
- ascending and descending colon
- aorta
- IVS
What are contained within the fold of the peritoneum?
- blood vessels
- lymph vessels
- nerves
What is the mesentery? What does it do?
- double fold of peritoneum that extends anteriorly from the posterior abdominal wall to envelope completely a loop of small bowel
- loosely connects small bowel to abdominal cavity
What is the omentum? What does it do?
- double fold of peritoneum that extends from the stomach to another organ
- Lesser omentum: extends superiorly from the lesser curvature to portions of the liver
- Greater omentum: extends inferiorly from the greater curvature to the transverse colon, drapes down over small bowel and back up to form an apron “fatty apron” provides insultation
What is the mesocolon? What does it do?
-part of the peritoneum that attaches the colon to the abdominal wall
4 forms:
-ascending, transverse, descending, and sigmoid/pelvic portions (named according to which part of the colon they attach to the abdominal wall)
What are the greater and lesser sac?
-divisions of the peritoneal cavity
Another name for the lesser sac?
- small upper posterior portion of the peritoneal cavity
- “omentum bursa”
Retroperitoneal organs?
Behind peritoneum
- kidneys
- ureters
- adrenal glands
- pancreas
- C-loop of duodenum
- ascending and descending colon
- upper rectum
- abdominal aorta
- IVC
Are retroperitoneal or intraperitoneal organs less mobile (move around less?)
Retroperitoneal because intraperitoneal organs are loosely attached by the mesentery
Infraperitoneal organs?
Under/beneath the peritoneum in the true pelvis
- lower rectum
- urinary bladder
- reproductive organs
Intraperitoneal organs?
Organs that are partially/completely covered by some type of visceral peritoneum, but are not retro or infra peritoneal
- liver
- gallbladder
- spleen
- stomach
- jejunum
- ileum
- cecum
- transverse colon
- sigmoid colon
4 abdominal quadrants?
- RUQ
- LUQ
- RLQ
- LLQ
Organs contained in the RUQ?
- liver
- gallbladder
- right hepatic flexure
- duodenum
- head of pancreas
- right kidney
- right suprarenal gland
Organs contained in the LUQ?
- spleen
- stomach
- left colic flexure
- tail of pancreas
- left kidney
- left suprarenal gland
Organs contained in t-he RLQ?
- ascending colon
- vermiform appendix
- cecum
- 2/3 of ileum
- ileocecal valce
Organs contained in the LLQ?
- descending colon
- sigmoid colon
- 2/3 jejunum
9 abdominal regions
- R/L hypochondriac
- R/L lumbar (lateral)
- R/L inguinal (iliac)
- epigastric
- umbilical
- hypogastric (pubic)
2 transverse planes separating the 9 abdominal regions?
- Transpyloric plane (lower L1)
- Transtubercular plane (L5)
7 landmarks of the abdomen?
- Xiphoid process (T9/T10): superior margin of abdomen
- Lower Costal Margin (L2/L3): used to locate upper abdo organs
- Iliac Crests (L4/L5): corresponds to mid abdomen
- ASIS: secondary landmark for general abdo positioning
- Greater Trochanter: superior border of symp
- Symphysis Pubis: inferior margin of abdomen
- Ischial tuberosity: lower margin on PA abdomen, 1-4cm below symph
What is the most commonly used landmark?
Iliac crests
Exposure factors for abdomen?
70-80kVp at 10mAs
Ascites?
Fluid in the peritoneal cavity
- caused by cirrhosis of the liver or metastatic disease to the peritoneal cavity
- general abdominal haziness (increase technique)
Pneomoperitoneum?
Free air in the peritoneal cavity
- caused by perforation (ulcer) or trauma
- small amounts of air can be visualized 2-3weeks post abdominal surgery-best demonstrated with horizontal beam upright abdomen or chest
- decrease technique because of air
Dynamic or mechanical bowel obstruction? Causes?
Complete/nearly complete blockage of flow to the intestinal contents caused by:
- Fibrous adhesion
- Crohn’s disease
- Intussusception
- Volvulus
What is a fibrous adhesion?
Most common mechanical obstruction
-fibrous band of tissue interrelates with the intestine causing a blockage
What is Crohn’s disease?
“Regional enteritis”: chronic inflammation of (all layers) of the intestinal wall
- common in young adults
- fistulas form
- common in terminal ileum and proximal colon
What is intussusception?
Telescoping of one section of bowel into another
- common in terminal ileum
- common in children
What is a volvulus?
Twisting of a loop of intestine
Ileus (non mechanical) bowel obstruction?
- adynamic (without power/force)
- caused by peritonitis or paralysis ileus (lack of intestinal mobility)
- abdominal surgery can cause
- large air fluid levels and no obvious obstruction
- decrease technique because of air
What is ulcerative colitis?
- chronic inflammation of the colon in young adults primarily
- common in the rectosigmoid region
- can cause toxic megacolon with potential perforation
- decrease technique because of air
What is done to demonstrate free air below the diaphragm better?
PA chest: exposure technique for chest better demonstrates air
When the kidneys are of primary interest, is a PA or AP less desirable?
PA because increased OID
What can a dorsal decubitus abdomen demonstrate?
- calcification of the aorta or other vessels
- umbilical hernia
- aneurysms
What does a true lateral demonstrate?
Foreign bodies
Indications for a 3 view abdomen?
- ileus
- ascites
- performed bowel viscus
- intra-abdominal mass
- post-operative
What can happen if you don’t decrease your technique when theres air in the abdomen?
Picture may be overexposed
How much do you decrease your technique for air in the abdomen?
- decrease mAs 30-50%
- decrease kVp 5-8%
What is a spinal stimulator implant?
- placed under the skin in the abdomen, leads go to spinal canal
- to treat chronic pain
Widest part of the abdomen on different body habitus?
- Hypersthenic: short and wide abdo, upper abdomen widest
- Asthenic: long and narrow abdo, lower abdomen widest
How much does the diaphragm move from inspiration to expiration? Vertebral levels?
4”
- inspiration: as low as T12
- expirationL T8/T9
What happens if 3 AEC cells are selected on inspiration?
-underexposed because side cells are over lung
Rotation on an abdomen decreases visualization of what?
Fat lines
What does enlargement of the fat strips indicate?
Ascites
Including what vertebral level will include both diaphragms?
T8
If the MSP is not parallel to the IR, what happens?
- decreases visualization of fat lines
- when rotated fat shifts anterior or posterior to muscle and eliminates subject contrast
Why do we do a LLD?
So the air rises away from the stomach bubble
How long should a patient lie on their side or be upright before we take the respective upright or decubitus picture?
5 mins
-10-20 preferred
To allow air to rise and fluid to settle
What do we do for patients with wide hips on a LLD?
-include right hemidiaphragm to iliac wing
What kind of filter do we use for a LLD? Why?
Wedge compensating filter because the belly drops to the lower side and makes it thicker
