First Aid Embryology

Question 1

Foregut consists of

Answer 1

esophagus to the upper duodenum

Question 2

Midgut consists of

Answer 2

lower duodenum to proximal 2/3 of transverse colon

Question 3

Hindgut consists of

Answer 3

distal 1/3 of transverse colon to anal canal above pectinate line

Question 4

Mid gut development

Answer 4

6th week - physiologic midgut herniates through umbilical ring

10th week - returns to abdominal cavity + rotates around superior mesenteric artery (SMA) total 270° counterclockwise

Question 5

Ventral wall defects

Answer 5

developmental defects due to failure of rostral fold closure (eg sternal defects [ectopia cordis]), lateral fold closure (eg, omphalocele, gastroschisis), or caudal fold closure (eg, bladder exstrophy)

Question 6

Gastroschisis etiology

Answer 6

Extrusion of abdominal contents through abdominal folds (typically right of the umbilicus)

Question 7

Gastroschisis coverage

Answer 7

not covered by peritoneum or amnion

“The abdominal contents are coming out of the G”

Question 8

Gastroschisis associations

Answer 8

cot associated with chromosome abnormalities

Question 9

Gastroschisis overview

Answer 9

TBD

Question 10

Omphalocele etiology

Answer 10

Failure of lateral walls to migrate at the umbilical ring -> persistent midline herniation of abdominal contents into umbilical cord

Question 11

Omphalocele coverage

Answer 11

Surrounded by peritoneum (light gray shiny sac)

“Abdominal contents are sealed in the O”

Question 12

Omphalocele associations

Answer 12

Associated with congenital anomalies

• trisomy 13
• trisomy 18
• Beckwith-Wiedermann syndrome

And other structural abnormalities

• cardiac
• GU
• neural tube

Question 13

Omphalocele overview

Answer 13

TBD

Question 14

Description of Congenital umbilical hernia

Answer 14

failure of the umbilical ring to close after physiologic herniation of the intestines

Small defects usually close spontaneously

Question 15

Tracheoesophageal anomalies

Answer 15

Esophageal atresia with distal tracheoesophageal fistula (TEF) is the most common (85%) and often presents as polyhydramnios in utero (due to inability of fetus to swallow amniotic fluid).

Neonates drool, choke and vomit with first feeding, TEFs allow air to enter the stomach (visible on CXR)

Cyanosis is 2° to laryngospasm (to avoid reflux-related aspiration

Clinical test: failure to pass nasogastric tube into stomach

Question 16

Clinical test for Esophageal Atresia w/ distal TEF

Answer 16

Clinical test: failure to pass nasogastric tube into stomach

Question 17

TEF AKA

Answer 17

Tracheoesophageal fistula

Question 18

Describe H-type TEF

Answer 18

the fistula resembles the letter H

Question 19

Describe pure Esophageal Atresia

Answer 19

CXR shows gasless abdomen

Question 20

Identify structures and pathology

Answer 20

Question 21

Describe presentation of intestinal atresia

Answer 21

Present with bilious vomiting and abdominal distension within first 1-2 days of life

Question 22

What is duodenal atresia?

Answer 22

Caused by failure of duodenum to recanalize

Duodenal atresia is a condition in which the first part of the small bowel (the duodenum) has not developed properly. It is not open and cannot allow the passage of stomach contents.

Question 23

Duodenal atresia associations

Answer 23

• Associated with “double bubble” (dilated stomach, proximal duodenumm) on x-ray
• Associated with down syndrome

Question 24

Jejunal and ileal atresia description

Answer 24

Jejunal or ileal Atresia is a birth defect in which the fold of the stomach membrane needed to connect the small intestine to the back wall of the abdomen is, in part, absent. As a result, a portion of the small intestine (the jejunal) twists about one of the arteries to the colon. This twisting may be so severe that the artery in question is completely blocked (atrasia). It is sometimes compared to an apple peel in appearance.

disruption of mesenteric vessels -> ischemic necrosis -> segmental resorption (bowel discontinuity or “apple peel”)

Question 25

What is the most common cause of gastric outlet obstruction in infants?

Answer 25

Hypertrophic pyloric stenosis

Question 26

Signs of hypertrophic pyloric stenosis

Answer 26

* Palpable olive-shaped mass in the epigastric region * visible peristaltic waves * nonbilious projectile vomiting around 2-6 weeks old

Question 27

hypertrophic pyloric stenosis is most common in?

Answer 27

Firstborn males

Question 28

Hypertrophic pyloric stenosis associations

Answer 28

associated with exposure to macrolides

Question 29

Imaging of hypertrophic pyloric stenosis

Answer 29

ultrasound shows thickened and lengthened pylorus

Question 30

Treatment of hypertrophic pyloric stenosis

Answer 30

surgical incision (pyloromyotomy)

Question 31

Complications of hypertrophic pyloric stenosis

Answer 31

Results in hypokalemic hypochloremic metabolic alkalosis (2° to vomiting of gastric acid and subsequent volume contraction

Question 32

Identify structures and pathology

Answer 32

Hypertrophic pyloric stenosis

Question 33

Pancreas derived from?

Answer 33

Foregut

Question 34

Pancrease development

Answer 34

ventral pancreatic buds contribute to uncinate process and main pancreatic duct The dorsal pancreatic bud alone becomes the body, tail, isthmus and accessory pancreatic duct Both ventral and dorsal buds contribute to the pancreatic head

Question 35

Describe annular pancreas

Answer 35

abnormal rotation of ventral pancreatic bud forms a ring of pancreatic tissue -\> encircles the 2nd part of the duodenum may cause duodenal narrowing and vomiting

Question 36

Pancreas divisum

Answer 36

ventral and dorsal parts fail to fuse at 8 weeks common anomaly mostly asymptomatic but may cause chronic abdominal pain and/or pancreatitis

Question 37

Spleen derived from

Answer 37

Spleen arises in mesentery of stomach (hence is mesenchymal) but has foregut supply (celiac trunk -\> splenic artery)

Question 38

Retroperitoneal structures

Answer 38

SAD PUCKER **S**uprarenal (adrenal) glands **A**orta and IVC **D**uodenum (2nd through 4th parts **P**ancreas [except tail] **U**reters **C**olon (descending and ascending) **K**idneys **E**sophagus [thoracic portion] **R**ectum (partially)

Question 39

Identify structures

Answer 39

Question 40

Identify structures

Answer 40

Question 41

Falciform ligament connects

Answer 41

Liver to anterior abdominal wall

Question 42

Falciform ligament structures contained

Answer 42

ligamentum teres hepatis (derivative of fetal umbilical vein) Patent paraumbilical veins

Question 43

Falciform ligament is derived from

Answer 43

derivative of ventral mesentery

Question 44

Hepatoduodenal ligament connects

Answer 44

liver to duodenum

Question 45

Hepatoduodenal ligament structures contained

Answer 45

Portal triad (Proper hepatic artery, portal vein, common bile duct)

Question 46

Describe the Pringle maneuver

Answer 46

* The Hepatoduodenal ligament may be compressed between thumb and index finger placed in omental foramen to control bleeding

Question 47

Hepatoduodenal ligament location

Answer 47

Part of the lesser omentum Borders the omental foramen which connects the greater and lesser sacs

Question 48

Gastrohepatic ligament connects

Answer 48

liver to lesser curvature of stomach

Question 49

Gastrohepatic ligament structures contained

Answer 49

Gastric vessels

Question 50

Gastrohepatic ligament location

Answer 50

Part of the lesser omentum and connects liver to lesser curvature of the stomach and separates greater and lesser sacs on the right

Question 51

Sugical considerations of gastrohepatic ligament

Answer 51

May be cut during surgery to access the lesser sac

Question 52

This May be cut during surgery to access the lesser sac

Answer 52

Gastrohepatic ligament

Question 53

Gastrocolic ligament connects

Answer 53

Greater curvature of stomach and transverse colon

Question 54

Gastrocolic ligament structures contained

Answer 54

gastroepiploic arteries

Question 55

Gastrocolic ligament location

Answer 55

part of the greater omentum and connects the greater curvature of the stomach to the transverse colon

Question 56

Gastrosplenic ligament connects

Answer 56

greater curvature of the stomach and spleen

Question 57

Gastrosplenic ligament structures contained

Answer 57

short gastrics left gastroepiploic vessels

Question 58

Gastrosplenic ligament location

Answer 58

* Separates greater and lesser sacs on the left and connects the greater curvature of the stomach and the spleen * Part of the greater omentum

Question 59

Splenorenal ligament connects

Answer 59

Spleen to posterior abdominal wall

Question 60

Splenorenal ligament structures contained

Answer 60

* Splenic artery and vein * vein of pancreas

Question 61

Identify structures

Answer 61