1
Q
PRONEPHROS
A
RUDIMENTARY AND NON-FUNCTIONAL
2
Q
MESONEPHROS
develop into what?
A
MESONEPHRIC DUCTS-DEVELOP INTO GENITALS
3
Q
METANEPHROS
A
PERMANENT KIDNEY
4
Q
IF THERE ARE KIDNEY DEVELOPMENT PROBLEMS…
A
CHECK GENITALS (they form from the same buds)
5
Q
MESONEPHROS
A
Appear late in the 6 week LMP
❖ Caudal to the pronephros
❖ Approximately 40 glomeruli with mesonephric tubules
❖ The mesonephros create urine between weeks 6 to 10, until the permanent kidneys
begin to function
❖ The mesonephros degenerate toward the end of the first trimester (3 months)
❖ their tubules become the efferent ductules of the testes.
❖ The mesonephric ducts have several adult derivatives in males (Efferent ductules of
testis, epididymis, Ductus deferens)
❖ Primordia of the permanent kidneys—begin to develop early in the 5th week
from conception (7 LMP)
❖ Become functional approximately 9th (11 LMP)
❖ Formation continues throughout fetal life.
❖ The urine is excreted into the amniotic cavity and forms a portion of the
amniotic fluid.
6
Q
KIDNEYS DEVELOP IN THE
A
FETAL PELVIS
7
Q
KIDNEYS DEVELOP WITHIN THE FETAL PELVIS IN
A
7TH MENSTRUAL WEEK
8
Q
KIDNEYS ASCEND INTO THE POSTEROLATERAL RETROPERITONEUM BY WEEK
A
11LMP
9
Q
URINE IS FIRST PRODUCED BY THE KIDNEYS AROUND THE
A
11 TO 12 LMP
10
Q
ADRENAL GLAND EMBRYOLOGY IS UNRELATED TO
A
GU TRACT
GENITAL SYSTEM RELATED TO URINARY EMBRYOLOGY
11
Q
what develops in males
A
EFFERENT DUCTULES OF TESTES
EPIDIDYMIS
VAS DEFERENS
SEMINAL VESICLES
EJACULATORY DUCT
12
Q
what develops in females
A
FALLOPIAN TUBE
UTERUS
UPPER VAGINA
13
Q
kidneys are observed by ___ WEEKS (TA) POSTERIORLY ON EITHER
SIDE OF THE SPINE
must be seen by _____ weeks
A
15 weeks
18 weeks
14
Q
kidneys are _____ in long axis
____ in transverse axis
A
ELLIPTICAL - long axis
CIRCULAR - transverse axis
15
Q
kidneys 2ND TRIMESTER APPEARANCE
A
OVOID STRUCTURES
WITH AN INDISTINCT BORDER
16
Q
WITH INCREASING MATURITY the kidneys…
A
BORDERS AND THE
PELVIS WILL BE MORE DEFINED
17
Q
kidneys 3rd trimester appearance
A
internal renal
anatomy well defined
- Renal pyramids
- Cortex (medulla)
- Renal margins (perirenal and sinus fat)
18
Q
NORMAL FOR RENAL PELVIS TO…
A
CONTAIN A SMALL AMOUNT OF
FLUID - NORMAL VARIANT (<5MM)
19
Q
AP Renal Measurements
A
less then or equal to 5mm = normal
5-10mm =-5 mm probably normal, follow up
greater then or equal to 10mm = always abnormal
20
Q
renal length in mm = …
A
gestational age RENAL LENGTH(MM) = GA (18-21 WEEKS)
20 wks = 20mm
30 wks = 30mm
21
Q
normal fetal ureter =
A
1mm (therefore not seen)
visualization suggests pathology
22
Q
bladder
A
ANECHOIC STRUCTURE
- FETUS VOIDS ABOUT ONCE PER HOUR
- RARELY COMPLETELY EMPTY
- LOCATED MIDLINE IN LOWER PELVIS
- COMPLETELY DEVELOPED AT 12 WKS
- SONOGRAPHICALLY SEEN AT 13 WKS
- VISUALIZATION IS AN INDICATION OF RENAL FUNCTION
- AFTER 14 WEEKS, TWO THIRDS OF THE NORMAL AMNIOTIC FLUID IS PRODUCED
BY FETAL URINATION AND ONE THIRD FROM PULMONARY FLUID
23
Q
after 14 weeks, _______ of the normal amniotic fluid is produced by _______
A
- AFTER 14 WEEKS, TWO THIRDS OF THE NORMAL AMNIOTIC FLUID IS PRODUCED
BY FETAL URINATION AND ONE THIRD FROM PULMONARY FLUID
24
Q
adrenal glands
A
- SUPERIOR TO KIDNEYS
- APPEAR LARGE IN UTERO
- IN THE 3RD TRIMESTER AND AT BIRTH THEY ARE
20 TIMES THEIR ADULT SIZE - LINEAR ECHOGENIC CENTER (MEDULLA) WITH
HYPOECHOIC RIND LIKE RIM (CORTEX)
25
genitalia
* OBSERVATION IS DEPENDENT ON FETAL LIE, FETAL LEG POSITION
AND AN ADEQUATE AMOUNT OF FLUID
* SCANNING AT TANGENTIAL (OBLIQUE) ANGLES INFERIOR TO THE
BLADDER
* ALMOST IMPOSSIBLE TO IDENTIFY GENDER IN A BREECH FETUS
* MAY BE SEEN AS EARLY AS 16 WEEKS (14-1 6 WK) ALTHOUGH MORE
READILY DEFINED BY 20 TO 22 WEEKS
* TESTICLES DESCEND INTO SCROTUM AT 28 WEEKS
* SCROTUM APPEARS AS A BILATERAL SOFT TISSUE MASS SEPARATED BY
A LINEAR ECHOGENIC LINE REPRESENTING THE SCROTAL SEPTUM
* A SMALL HYDROCELE (FLUID AROUND THE SCROTUM) IS A NORMAL
BENIGN FINDING IN UTERO
* FEMALES MAY BE RECOGNIZED BY OBSERVATION OF THE LABIA WITH A
LINEAR ECHO IN BETWEEN REPRESENTING THE LABIA MINORA
* NORMAL LABIA MAY APPEAR EDEMATOUS AND SWOLLEN - DO NOT
CONFUSE WITH SCROTUM.
* GENDER IDENTIFICATION REQUIRED WHEN SCANNING MULTIPLES TO
DETERMINE THEIR CHORIONICITY
26
genetalia may be seen as early as _______ although more readily defined by _________
16 weeks
20 to 22 weeks
27
testicles descend into scrotum at ______
28 weeks
28
what is a normal benign finding in utero
A SMALL HYDROCELE (FLUID AROUND THE SCROTUM)
29
Foregut
Primordial pharynx and its derivatives
* Lower respiratory system
*ESOPHAGUS AND STOMACH
*DUODENUM - JUST PROXIMAL TO THE OPENING OF THE BILE DUCT
* LIVER, BILIARY APPARATUS (HEPATIC DUCTS, GALLBLADDER, AND BILE DUCT) AND PANCREAS
30
Midgut
The small intestine, including the duodenum distal to the
opening of the bile duct
* The cecum, appendix, ascending colon, and right half
to two thirds of the transverse colon
31
Hindgut
THE LEFT THIRD TO HALF OF THE TRANSVERSE COLON, THE DESCENDING COLON AND SIGNMOID COLON, THE RECTUM, AND THE SUPERIOR PART OF THE ANAL CANAL
the epithelium of the urinary bladder and most of the urethra
32
endoderm
mucosal epithelium
mucosal glands
submucosal glands of the GI tract.
33
mesoderm
lamina propria
muscularis mucosae
submucosal connective tissue and blood vessels
muscularis externa, and adventitia/serosa
34
neural crest
neurons and nerves of the submucosal and
myenteric plexes
35
FETAL ESOPHAGUS
RUNS FROM PHARYNX TO THE STOMACH
* CAN BE VISUALIZED AS EARLY AS 15 WEEKS GESTATION AS TWO ECHOGENIC PARALLEL LINES IN THE
NECK AND POSTERIOR CHEST
* AFTER 26 WEEKS IT APPEARS AS A TUBULAR ECHOGENIC STRUCTURE HAVING ONE OF TWO PATTERNS:
1) TWO PARALLEL ECHOGENIC LINES
2) SEVERAL PARALLEL ECHOGENIC LINES (THE "MULTILAYERED PATTERN"). THIS IS SEEN IN 49% OF CASES PRIOR TO 26 WEEKS
GESTATION AND IN 87% OF CASES AFTER 26 WEEKS GESTATION
* THE THORACIC ESOPHAGUS CAN BE VISUALIZED IN ABOUT 90% OF CASES, THE CERVICAL ESOPHAGUS (BETWEEN THE
PHARYNX AND THE UPPER LIMIT OF THE CHEST) IN 19% OF CASES AND THE ABDOMINAL SEGMENTS (BETWEEN DIAPHRAGM
AND STOMACH) IN 30% OF CASES (1)
SWALLOWING MAY BE SEEN INTERMITTENTLY (1-2 MOVEMENTS OF THE PHARYNX OR MANDIBLE PER MINUTE)
36
trachea is ______ and bifurcates into _______
TRACHEA IS ANTERIOR AND BIFURCATES INTO THE MAIN BRONCHI
37
esophagus continues ...
ESOPHAGUS CONTINUES WITHOUT DIVISION
38
trachea compared to esophagus
TRACHEA DOES NOT SHOW VARIATION IN SIZE UNLIKE THE ESOPHAGUS
39
azygous vein courses...
AZYGOUS VEIN COURSES PARALLEL AND TO THE RIGHT OF THE SPINE
40
from what structure does the liver develop?
FOREGUT
41
fetal liver appears ...
LIVER APPEARS EVENLY HOMOGENEOUS MUCH
LIKE AN ADULT LIVER
42
left lobe of liver compared to right lobe
left lobe bigger)
L >= R LOBE DUE TO BLOOD SUPPLY IN UTERO
43
visualization of spleen
SPLEEN POORLY VISUALIZED
– TENDS TO BE LESS
ECHOGENIC THAN SURROUNDING STRUCTURES
44
Gallbladder
* OVOID OR TEAR DROP SHAPED CYSTIC STRUCTURE
* LOCATED ALONG LOWER LIVER BORDER
* VISUALIZED IN MOST FETUSES -AFTER 20 WEEKS-
* NONVISUALIZATION IS OF NO CONSEQUENCE
45
gallbladder is visualized in most fetuses...
after 20 weeks
46
fetal stomach seen as early as
11 weeks
47
non visualization of the stomach after _______ may result in ______
NONVISUALIZATION OF THE STOMACH AFTER 19
WEEKS MAY RESULT IN AN ABNORMAL FETAL
OUTCOMES
48
fetal stomach contains...
CONTAINS THE AMNIOTIC FLUID THAT IS NORMALLY
SWALLOWED BY THE FETUS
49
when might the fetal stomach not be seen
MAY NOT BE SEEN IN CASES OF LOW AMNIOTIC
FLUID OR ESOPHAGEAL ATRESIA
* NOT SEEN IF STOMACH HAS RECENTLY EMPTIED INTO
THE SMALL BOWEL. FILLING TIMES USUALLY NOT
MORE THAN 45 MINUTES
50
fetal stomach is on the same side as ...
On same side as apex of the heart
(Situs solitus – normal
arrangement of the organs in the
chest and abdomen)
51
small bowel
SMALL BOWEL INITIALLY APPEARS AS AN
ECHOGENIC PSEUDOMASS (NO SHADOWING)
* BECOMES LESS ECHOGENIC WITH TIME AS GREATER AMOUNTS OF FLUID ENTER THE
BOWEL
* BY 30 WEEKS SMALL BOWEL PERISTALSIS
MAY BE OBSERVED
* SMALL BOWEL MAXIMUM DIAMETER < 5MM
52
when might bowel peristalsis be observed in fetal stomach
small bowel max diameter?
* BY 30 WEEKS SMALL BOWEL PERISTALSIS
MAY BE OBSERVED
* SMALL BOWEL MAXIMUM DIAMETER < 5MM (less than)
53
hyper echoic bowel associated with...
ASSOCIATED WITH PATHOLOGY
“ECHOGENICITY OF BOWEL > FETAL BONE”
--> brighter than fetal bone
54
normal large bowel/colon
The colon is seen near the end of the second trimester
as a long tubular hypoechoic structure with well-
defined walls.
The haustral folds of the colon help to
differentiate it from the small bowel.
After 14 weeks of gestation, the lipid is
absorbed from the fetal colon, and the
remaining contents collect in the colon as
meconium
55
when is the colon seen?
what helps differentiate the large bowel/colon from small bowel
The colon is seen near the end of the second trimester
The haustral folds of the colon help to
differentiate it from the small bowel.
56
when might small bowel be differentiated from large bowel, what might be observed?
SMALL BOWEL MAY BE DIFFERENTIATED FROM LARGE BOWEL AFTER 20 WEEKS BY ITS
CENTRALLY LOCATED POSITION AS A CLUSTER OF BOWEL LOOPS.
PERISTALSIS AND
EVEN FLUID FILLED BOWEL LOOPS MAY BE OBSERVED.
57
how does large bowel appear, what is it identified by?
LARGE BOWEL (ASCENDING, TRANSVERSE AND DESCENDING COLON) APPEARS
HYPOECHOIC AND IS IDENTIFIED BY ITS PERIPHERAL LOCATION.
58
large bowel contains what liquid?
LARGE BOWEL CONTAINS LIQUID MECONIUM
59
what is MECONIUM
MECONIUM IS DEFINED AS THE CONTENTS OF THE BOWEL.
AT BIRTH IT APPEARS AS A
DARK GREENISH MUCOUS MATERIAL IN THE STOOLS THAT ARE INITIALLY PASSED BY
THE FETUS
60
what is the maximum diameter of the colon at 3rd trimester?
23MM AT TERM
61
what is the normal position of the heart?
- Mostly left chest
* Apex points to the left
* Rt ventricle anterior
* Lt atrium posterior
* Fetal Heart more horizontal in
chest due to large liver
62
normal axis and normal range of heart
Normal axis = 45 ± 20° (2 standard deviations).
Normal range = 22°-75° (1).
63
Levocardia
The cardiac apex points to the left
(normal).
64
Mesocardia
The cardiac apex points to the
midline.
65
Dextrocardia
The cardiac apex points to the right
66
Label the chambers in this image.
Which chamber is most posterior and which is most anterior?
RV most anterior.
* LA most posterior
67
What two approaches to 4 ch view we can use?
Normal four-chamber view
* Transverse plane of the chest
* Level of the fourth rib
* One complete rib on each side of lateral chest wall
* Types - Apical; Subcostal
68
What can we asses on 4 chamber view?
* Cardiac
axis
Symmetry of the chambers
Size of the chambers
Contractility
Semptums
69
What is the Moderator Band?
Where do we see it?
Location:
- located in right ventricular apex that
connects the interventricular septum to the anterior papillary muscle.
- does not seem to be attached
to one single side, but rather crossing the lower portion of the right
ventricular chamber.
Function:
- to act as a primary conduction path in
to the free wall originating from the right bundle branch
70
Where would you see the flap of foramen ovale?
The flap of the foramen ovale is seen in the left atrium on the four-chamber view, as a thin mobile flap forming the valve of the foramen ovale.
71
How does one obtain a Subcostal Four Chamber View of the Heart
This view is obtained by imaging the fetal chest in a transverse projection from the
anterior chest wall and angling the transducer in a cephalad direction.
72
What structures can we see on the LVOT?
aorta
--> LVOT (Aorta)
The aorta arises from the posterior aspect of the left ventricle
The aorta (Ao) and pulmonary artery (PA) cross over each other as they exit
their respective ventricles of the heart
73
What structure can be see on Five chamber view of
the heart?
The 5-chamber view shows the four chambers of the heart plus the aorta (LVOT) coming off the left ventricle.
(Right atrium
✔ Left atrium
✔ Right ventricle
✔ Left ventricle
✔ Interventricular septum
✔ Aortic root / Ascending aorta (LVOT) ← the added “5th chamber”)
The five chamber view is obtained by angling the transducer cephalad and anterior
from the four chamber view.
74
What structures can we see on RVT?
RVOT (Pulmonary Artery)
The pulmonary artery arises from the anterior aspect of the right ventricle
Chat: RVT view shows the right ventricle, pulmonary valve, main pulmonary artery, its bifurcation, and the ductus arteriosus.
75
What structures can we see on 3 vessels view?
Pulmonary artery, aorta, and superior vena cava — arranged from left to right and decreasing in size
76
On sagittal view of thoracic aorta what vessels are
shown on so called “Hokey stick” appearance and
what vessels are shown on “candy cane”?
1. “Hockey Stick” Appearance:
- This is seen in the ductal arch.
Vessels seen:
- Main pulmonary artery (MPA)
- Ductus arteriosus
- Descending aorta
Why it looks like a hockey stick:
- The pulmonary artery comes straight out of the right ventricle.
- It curves smoothly through the ductus arteriosus.
- Then it continues as the descending aorta → forming the hockey-stick curved shape.
Key point:
✔ Ductal arch = Hockey Stick
2. “Candy Cane” Appearance
This is seen in the aortic arch.
Vessels seen:
- Ascending aorta
- Aortic arch (“candy cane” curve)
Three arch branches:
- Brachiocephalic (innominate) artery
- Left common carotid artery
- Left subclavian artery
- Descending aorta
Why it looks like a candy cane:
The ascending aorta sweeps upward, arches, then smoothly curves downward — just like a candy cane shape.
Key point:
✔ Aortic arch = Candy Cane
77
In sagittal view of thoracic aorta, what vessels are shown
Image A: Ductal Arch
Image B: Aortic Arch
78
how does one acquire the "hockey stick" view?
This view is obtained by continuing to rotate the transducer from the long-axis view of the
left ventricle to an almost sagittal view of the fetus. This results in the "hockey stick"
appearance of the pulmonary artery - ductus outflow tract.
79
Sagittal view (“Hockey stick”) =
Ductal arch
80
Sagittal view (“Candy Cane”) =
Aortic arch
81
List the images that should be taken for the fetal heart?
1) 3-vessel view
2) 4-chamber
3) Situs view/transverse view of upper abdomen
4) 5-chamber (LVOT)
5) RVOT view
6) Basal Short-axis views
7) Aortic arch (candy cane)
chat also said/added:
3-vessel–trachea view
Ductal arch (hockey stick)
SVC/IVC view
82
What are the vascular adaptation in fetal
circulation? (write done 5)
1. Ductus Venosus
Connects:
➡ Umbilical vein → Inferior vena cava (IVC)
Purpose:
Bypasses the liver
Sends oxygen-rich placental blood directly to the heart
2. Foramen Ovale
Connects:
➡ Right atrium → Left atrium
Purpose:
Shunts most oxygenated blood across the atria
Bypasses the lungs (which are non-functional in utero)
3. Ductus Arteriosus
Connects:
➡ Pulmonary artery → Descending aorta
Purpose:
Diverts blood away from the lungs
Ensures blood reaches the lower body and placenta
4. Umbilical Vein
Connects:
➡ Placenta → Fetus
Purpose:
Carries oxygen-rich blood to the fetus
5. Umbilical Arteries (2)
Connect:
➡ Fetal internal iliac arteries → Placenta
Purpose:
Return deoxygenated blood to the placenta for oxygen exchange
83
mnemonic to remember 5 vascular adaptation in fetal circulation and what vessels they connect
MNEMONIC #1: “Very Fast Ducks Use Umbrellas”
Each first letter matches the 5 major fetal shunts:
V – Ductus Venosus
➡ Umbilical Vein → IVC
F – Foramen Ovale
➡ Right Atrium → Left Atrium
D – Ductus Arteriosus
➡ Pulmonary Artery → Aorta
U – Umbilical Vein
➡ Placenta → Fetus
U – Umbilical Arteries (2)
➡ Fetal Iliac Arteries → Placenta
84
blood flow from and back to placenta visual
OBstetrical & Gynecological Sonography
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