Anatomy - Abdominal pain and likely sources

Question 1

List the sections of the small intestine

Answer 1

duodenum
-->
jejunum
-->
ileum

Question 2

List the sections of the large intestine

Answer 2

caecum
-->
ascending colon
-->
transverse colon
-->
descending colon
-->
sigmoid colon
-->
rectum
-->
anal canal
-->
anus

Question 3

List the sections of the colon

Answer 3

Caecum (--> appendix)
-->
ascending colon
-->
transverse colon
-->
descending colon
-->
sigmoid colon

Question 4

List the abdominal GI organs

Answer 4

oesophagus (distal part)

stomach

liver

gallbladder

pancreas

Intestines

rectum

Question 5

Describe the division of the abdominal GI organs

Answer 5

• foregut
• midgut
• hindgut

Each region has a distinct supplies:

• arterial
• venous
• lymphatic
• nervous

Question 6

What is the foregut?

Answer 6

oesophagus
–>
mid-duodenum

liver
gallbladder
spleen
1/2 of pancreas

Question 7

What is the midgut?

Answer 7

mid-duodenum
–>
proximal 2/3rds of transverse colon

1/2 of pancreas

Question 8

What is the hindgut?

Answer 8

distal 1/3rd of transverse colon
–>
1/2 of the anal canal

Question 9

List the 9 regions of the abdomen

Answer 9

• Right/Left Hypochondrium
• Epigastric
• Right/Left Lumbar
• Umbilical
• Right/Left Inguinal (iliac fossa)
• Pubic (suprapubic)

Question 10

Along what lines are the 9 abdominal regions divided

Answer 10

midclavicular line

subcostal line

trans-tubercular line

Question 11

List the 3 quadrants of the abdomen

Answer 11

Right/Left Upper Quadrants

Right/Left Lower Quadrants

Question 12

Along what lines are the 3 abdominal quadrants divided

Answer 12

medial line

trans-umbilical line

Question 13

List the anterior and lateral muscles of the abdomen

Answer 13

anterior:
- Rectus abdominis

Lateral:

• external oblique (outer)
• internal oblique (middle)
• transversus abdominis (inner)

Question 14

What lines the walls of the abdominopelvic cavity and its organs?

Answer 14

Peritoneum

body wall = parietal peritoneum
organs = visceral peritoneum

Question 15

Describe the peritoneum of the abdominopelvic cavity

Answer 15

semi-permeable

serous (secretes fluid)

a single continuous layer

is sensitive (nerves)

Question 16

Define the peritoneal cavity

Answer 16

cavity between the visceral and parietal peritoneum

Question 17

define the mesentary

Answer 17

double layer of peritoneum that attaches the intestines to the posterior abdominal wall

Double fold of peritoneum

Functions:

• storing fat
• supports blood vessels, lymphatics, and nerves

Question 18

List and define the relationships organs can have with the peritonuem

Answer 18

Intraperitoneal:

• mostly enclosed in visceral peritoneum
• connected to parietal peritoneum via a 2 layer sheet of peritoneum

Retroperitoneal:

• not fully enclosed in peritoneum
• is connected to the abdominal cavity wall

Mesenteric:
- with a mesentery

Question 19

Are the abdominal GI organs inside or outside the peritoneal cavity?

Answer 19

outside

Question 20

Contrast the organ mobility of intraperitoneal, retroperitoneal, and mesenteric organs

Answer 20

Intraperitoneal = minimal mobility

Retroperitoneal = no mobility

Mesenteric = very mobile

Question 21

Describe the greater and lesser sacs of the peritoneal cavity

Answer 21

2 areas separated by the omenta

But they communicate via the omental foramen

Question 22

describe the greater omentum

Answer 22

The peritoneum drapes off stomach then loops back to enclose the transverse colon

it is 4 layers thick

Question 23

describe the lesser omentum

Answer 23

superior to the stomach

Question 24

List the peritoneal pouches in males and females

Answer 24

Males:

rectovesical - (between bladder and rectum)

Female:

rectouterine - (between uterus and rectum)
vesico-uterine - (between bladder and uterus)

Question 25

Define ascitic fluid

Answer 25

excess fluid in the peritoneal cavity often collects in the peritoneal pouches

Question 26

# Define a paracentesis (aka abdominocentesis)

Answer 26

draining ascitic fluid from the peritoneal cavity - Needle must be placed lateral to the rectus sheath to avoid the inferior epigastric artery

Question 27

Describe the inferior epigastric artery

Answer 27

Ascends deep to rectus abdominis Arises from the external iliac

Question 28

Define referred pain

Answer 28

injury to one area that is felt in another region due to the area having shared innervation

Question 29

Describe the path of sympathetic nerves to the GI organs | except the adrenal glands

Answer 29

``` Leaves spinal cord at T2-5 --> enter the sympathetic chain --> leave the sympathetic chains in the abdominopelvic splanchnic nerves --> synapse at the prevertebral ganglia --> follow the aortic arterial branches (periarterial plexus) ```

Question 30

describe the prevertebral ganglia

Answer 30

located anterior to the descending aorta at the bifurcations of the major aortic branches - abdominopelvic splanchnic come in - periarterial plexus leaves

Question 31

describe the periarterial plexuses

Answer 31

nerves that travel with arteries, surrounding them in a plexus

Question 32

Describe the sympathetic innervation of the adrenal glands

Answer 32

fibres leave the spinal cord at T10-L1 --> enter the abdominopelvic splanchnic nerves --> follow the aortic arterial branches (periarterial plexus) --> synapse directly into adrenal gland

Question 33

Describe the parasympathetic innervation of the GI organs

Answer 33

Vagus (CN X): - - everything (all organs!) until the distal transverse colon Pelvic splanchnic nerves (S2,3,4): - everything below the distal end of the transverse colon

Question 34

Describe the vagal innervation of the GI organs

Answer 34

Does everything until the distal transverse colon Presynaptic fibres enter abdominal cavity on surface of the oesophagus --> Periarterial plexuses around the abdominal aorta --> Walls of the organs where they synapse in ganglia

Question 35

Describe the pelvic splanchnic innervation of the GI organs

Answer 35

does everything below the distal end of the transverse colon parasympathetic Leaves from S2,3,4

Question 36

How do visceral afferent nerve fibres get from the abdominal organs to the CNS?

Answer 36

Pain fibres from most of the abdominal organs run alongside sympathetic fibres to the spinal cord From: - foregut = enter at T6-T9 - midgut = enter at T8-T12 - hindgut = enter at T10-L2

Question 37

Where is abdominal GI visceral pain usually felt

Answer 37

Pain is usually felt along the dermatomes of the levels at which they enter the spinal cord (there is a little overlap) Pain is usually felt centrally (this is a type of referred pain)

Question 38

List some referred pain patterns

Answer 38

Usual dermatomal patterns liver and gallbladder --> right shoulder pancreas and stomach --> between shoulder blades appendix --> umbilical region

Question 39

Describe the pain progression in appendicitis

Answer 39

visceral pain is referred to the umbilical region (dull, general) --> inflammation rubs against the parietal peritoneum (sharp, localised)

Question 40

Describe the somatic innervation of the abdomen

Answer 40

Somatic motor, somatic sensory and sympathetic nerve fibres Carried in nerves that follow the dermatomes Thoracoabdominal nerves (7th-11th intercostal nerves): - Travel anteriorly, then leave the intercostal spaces, travel in the plane between the internal oblique and transversus abdominis The subcostal nerve (T12 anterior ramus) The iliohypogastric nerve (half of L1 anterior ramus) The ilioinguinal nerve (other half of L1 anterior ramus)