Gray's Anatomy – Abdomen Exam
Questions and Answers
A 1-year-old girl is admitted to the hospital with a palpable mass in her labia majora.
Radiographic examination reveals that a loop of intestine has herniated into the
visibly enlarged labium majus. This condition is due to failure of the processus
vaginalis to close off. From which of the following tissue layers is the processus
derived?
A. Parietal peritoneum
B. Extraperitoneal tissue
C. Transversalis fascia
D. Dartos fascia
E. Internal abdominal oblique aponeurosis - answer- A. The processus vaginalis
(meaning sheathlike process) is composed of parietal peritoneum that precedes the
testis as it "migrates" from a position in the upper lumbar wall to a position outside
the abdomen. This process usually obliterates, leaving only a distal portion that
surrounds most of the testis as the tunica vaginalis. Whereas these features are
typical of development in the male, females also have a processus vaginalis that
extends into the labia majus, although congenital inguinal hernias are more common
in males than females. The other listed structures are not involved in congenital
inguinal hernias. GAS 293; N 257; McM 272, 275
A 3-year-old boy is admitted to the hospital with signs of acute renal failure.
Radiologic studies reveal that the boy has bilateral masses involving both kidneys.
Examination of biopsy material confirms the diagnosis of Wilms tumor. Which of the
following gene mutations is the most common in Wilms tumor?
A. The gene responsible for WT1
B. The gene responsible for HGF
C. The gene responsible for VEGF
D. The gene responsible for GDNF
E. The gene responsible for FGF-2 - answer- A. Wilms tumor is a kidney malignancy
that usually occurs in children. It has recently been shown that it can be caused by
mutations in the WT1 gene, behaving according to the Knudson two-hit model for
tumor suppressor genes. GAS 373; N 308; McM 255, 258
Fusion of the caudal portions of the kidneys during embryonic development is most
likely to result in which of the following congenital conditions?
A. Bicornuate uterus
B. Cryptorchidism
C. Horseshoe kidney
D. Hypospadias
E. Renal agenesis - answer- C. During development, the kidneys typically "ascend"
from a position in the pelvis to a position high on the posterior abdominal wall.
Although the kidneys are bilateral structures, occasionally the inferior poles of the
two kidneys fuse. When this happens, the "ascent" of the fused kidneys is arrested
by the first midline structure they encounter, the inferior mesenteric artery. The
,incidence of horseshoe kidney is about 0.25% of the population. GAS 373; N 309;
McM 259, 250
Which of the following congenital malformations will most predictably result in
oligohydramnios?
A. Anencephaly
B. Pyloric stenosis
C. Renal agenesis
D. Tracheoesophageal fistula
E. Urethral atresia - answer- C. In normal kidney development the kidneys function
during the fetal period with the resulting urine contributing to the fluid in the amniotic
cavity. When the kidneys fail to develop (renal agenesis), this contribution to the fluid
is missing and decreased amniotic fluid (oligohydramnios) results. GAS 373; N 309;
McM 255, 256
Failure to urinate during embryonic or fetal life usually causes respiratory difficulties
postnatally. Which of the following relationships best describes this situation?
A. Oligohydramnios linked with hypoplastic lungs
B. Polycystic kidneys linked to tracheoesophageal fistula
C. Polyhydramnios
D. Renal agenesis linked to insufficient surfactant
E. Urethral obstruction linked to ectopic viscera - answer- A. There is some evidence
that oligohydramnios is linked to hypoplastic lungs. This is apparently not a genetic
link but rather related to the importance of adequate amniotic fluid in normal lung
development. GAS 167, 373; N 208; McM 199
A 4-year-old male child is admitted to the hospital with severe vomiting. Radiologic
examination and history taking reveals that the boy suffers from an annular
pancreas. Which of the following structures is most typically obstructed by this
condition?
A. Pylorus of the stomach
B. First part of the duodenum
C. Second part of the duodenum
D. Third part of the duodenum
E. Jejunum - answer- C. In normal pancreatic development a bifid ventral pancreatic
bud rotates around the dorsal side of the gut tube and fuses with the dorsal
pancreatic bud. Rarely, a portion of the ventral bud rotates around the ventral side of
the gut tube, resulting in an annular pancreas. The portion of the gut tube is the
same where the main pancreatic duct enters the second part of the duodenum
(along with the common bile duct). The incidence of annular pancreas is about 1 in
7000. GAS 336; N 281; McM 235
A 3-year-old male child is admitted to the pediatric clinic. Diagnosis reveals that the
intermediate portion of the processus vaginalis is not obliterated. Which of the
following conditions will most likely result from this?
A. Hypospadias
B. Sterility
C. Congenital hydrocele
D. Ectopic testis
,E. Epispadias - answer- C. The distal portion of the processus vaginalis contributes
to the tunica vaginalis that is related to the testis. If an intermediate portion of the
processus vaginalis persists, it often fills with fluid, creating a hydrocele. If the entire
processus vaginalis persists, the patient is likely to develop a congenital inguinal
hernia. GAS 269; N 365; McM 265, 266
Testicles are absent from the scrotum of a 1-year-old male admitted to the pediatric
clinic. The pediatrician examined the infant and palpated the testes in the inguinal
canal. Which of the following terms is used to describe this condition?
A. Pseudohermaphroditism
B. True hermaphroditism
C. Cryptorchism
D. Congenital adrenal hyperplasia
E. Chordee - answer- C. Cryptorchism, often called an undescended testis, is the
result of incomplete migration of the gonad from the abdomen to a location in the
scrotum where it is exposed to temperatures slightly lower than core body
temperature. This is important for spermatogenesis and testicular function. A testis
that cannot be surgically relocated into the scrotum is usually removed because it
would otherwise be prone to develop testicular cancer. GAS 293; N 364; McM 265,
266
A 28-year-old woman who is 8 months pregnant goes to the outpatient clinic for her
prenatal checkup. Ultrasound examination of the fetus reveals gastroschisis, with
herniation of the small bowel into the amniotic cavity. Failure of proper formation of
which of the following structure(s) has resulted in this condition?
A. Head fold
B. Tail fold
C. Neural folds
D. Lateral folds
E. Amnion - answer- D. The lateral folds are key structures in forming the muscular
portion of the anterior abdominal wall. Failure of the lateral folds can cause a minor
defect, such as an umbilical hernia, or a major defect, such as gastroschisis. GAS
265, 311; N 247; McM 222
Rotation of the stomach during development results in movement of the left vagus
nerve from its original position. Through approximately how many degrees of rotation
does the nerve move, and what is its final position?
A. 90 degrees to become the anterior vagal trunk
B. 90 degrees to become the posterior vagal trunk
C. 270 degrees to become the anterior vagal trunk
D. 270 degrees to become the posterior vagal trunk
E. 180 degrees to become the right vagal trunk - answer- A. Rotation of the gut tube
is a major event in the development of the gastrointestinal system. Parts of the tube
rotate 270 degrees, but the proximal foregut, specifically that portion that forms the
esophagus, rotates only 90 degrees. Looking from below (the standard CT or MRI
view), this rotation is counterclockwise. This brings the left vagus nerve onto the
anterior surface of the esophagus as it passes through the thorax. GAS 265, 363-
364; N 263; McM 241, 257
, A newborn baby was diagnosed with eventration of the diaphragm, wherein one half
of the diaphragm ascends into the thorax during inspiration, but the other half
contracts normally. What is the most likely cause of this condition?
A. Absence of a pleuropericardial fold
B. Absence of musculature in one half of the diaphragm
C. Failure of migration of the diaphragm
D. Failure of development of the septum transversum
E. Absence of a pleuroperitoneal fold - answer- B. The diaphragm develops from
several components. Initially, the septum transversum (which will become the central
tendon) forms in the cervical region, gaining innervation from C3, C4, and C5. Later,
myoblasts migrate in from the body wall to form the muscular part of the diaphragm,
often considered to be two bilateral hemidiaphragms. These muscles are innervated
by the phrenic nerves that are derived from C3, C4, and C5. Eventration of the
diaphragm occurs when one muscular hemidiaphragm fails to develop. With positive
pressure in the abdominal cavity, and low or negative pressure in the thoracic cavity,
abdominal organs are pushed into the thorax. The pleuroperitoneal folds contribute
to a portion of the diaphragm posteriorly. GAS 371; N 191, 192; McM 213, 260
A 2-day-old newborn male is cyanotic after attempts to swallow milk result in
collection of the milk in his mouth. After 2 days he develops aspiration pneumonia. A
tracheoesophageal fistula is suspected. Which of the following structures has most
likely failed to develop properly?
A. Esophagus
B. Trachea
C. Tongue
D. Tracheoesophageal septum
E. Pharynx - answer- D. The tracheoesophageal septum is the downgrowth that
separates the ventral wall of the foregut (esophagus) from the laryngotracheal tube.
The presence of a fistula would result in passage of fluid from the esophagus into the
trachea and could cause aspiration pneumonia. If the esophagus did not develop
correctly, as in esophageal atresia, it would end as a blind tube. This kind of defect,
although associated with tracheoesophageal fistula, is not the result of an opening
into the trachea, and pneumonia would not result. Abnormal tracheal development
can be associated with tracheoesophageal fistula, therefore, but it is not the direct
cause of it. Abnormal tongue development does not result in a tracheoesophageal
fistula. Abnormal development of the pharynx is not associated with a
tracheoesophageal fistula. GAS 172; N 230; McM 196
A 3-day-old newborn male has difficulties in breathing. A computed tomography (CT)
scan of his chest and abdomen reveals the absence of the central tendon of the
diaphragm. Which of the following structures most likely failed to develop properly?
A. Pleuroperitoneal folds
B. Pleuropericardial folds
C. Septum transversum
D. Cervical myotomes
E. Dorsal mesentery of the esophagus - answer- C. The septum transversum forms
the central tendon of the diaphragm. The pleuroperitoneal folds form the
posterolateral part of the diaphragm. The pleuropericardial folds separate the
pericardial cavity from the pleural cavity and form the fibrous pericardium. The
cervical myotomes form the musculature of the diaphragm. The dorsal part of the
Questions and Answers
A 1-year-old girl is admitted to the hospital with a palpable mass in her labia majora.
Radiographic examination reveals that a loop of intestine has herniated into the
visibly enlarged labium majus. This condition is due to failure of the processus
vaginalis to close off. From which of the following tissue layers is the processus
derived?
A. Parietal peritoneum
B. Extraperitoneal tissue
C. Transversalis fascia
D. Dartos fascia
E. Internal abdominal oblique aponeurosis - answer- A. The processus vaginalis
(meaning sheathlike process) is composed of parietal peritoneum that precedes the
testis as it "migrates" from a position in the upper lumbar wall to a position outside
the abdomen. This process usually obliterates, leaving only a distal portion that
surrounds most of the testis as the tunica vaginalis. Whereas these features are
typical of development in the male, females also have a processus vaginalis that
extends into the labia majus, although congenital inguinal hernias are more common
in males than females. The other listed structures are not involved in congenital
inguinal hernias. GAS 293; N 257; McM 272, 275
A 3-year-old boy is admitted to the hospital with signs of acute renal failure.
Radiologic studies reveal that the boy has bilateral masses involving both kidneys.
Examination of biopsy material confirms the diagnosis of Wilms tumor. Which of the
following gene mutations is the most common in Wilms tumor?
A. The gene responsible for WT1
B. The gene responsible for HGF
C. The gene responsible for VEGF
D. The gene responsible for GDNF
E. The gene responsible for FGF-2 - answer- A. Wilms tumor is a kidney malignancy
that usually occurs in children. It has recently been shown that it can be caused by
mutations in the WT1 gene, behaving according to the Knudson two-hit model for
tumor suppressor genes. GAS 373; N 308; McM 255, 258
Fusion of the caudal portions of the kidneys during embryonic development is most
likely to result in which of the following congenital conditions?
A. Bicornuate uterus
B. Cryptorchidism
C. Horseshoe kidney
D. Hypospadias
E. Renal agenesis - answer- C. During development, the kidneys typically "ascend"
from a position in the pelvis to a position high on the posterior abdominal wall.
Although the kidneys are bilateral structures, occasionally the inferior poles of the
two kidneys fuse. When this happens, the "ascent" of the fused kidneys is arrested
by the first midline structure they encounter, the inferior mesenteric artery. The
,incidence of horseshoe kidney is about 0.25% of the population. GAS 373; N 309;
McM 259, 250
Which of the following congenital malformations will most predictably result in
oligohydramnios?
A. Anencephaly
B. Pyloric stenosis
C. Renal agenesis
D. Tracheoesophageal fistula
E. Urethral atresia - answer- C. In normal kidney development the kidneys function
during the fetal period with the resulting urine contributing to the fluid in the amniotic
cavity. When the kidneys fail to develop (renal agenesis), this contribution to the fluid
is missing and decreased amniotic fluid (oligohydramnios) results. GAS 373; N 309;
McM 255, 256
Failure to urinate during embryonic or fetal life usually causes respiratory difficulties
postnatally. Which of the following relationships best describes this situation?
A. Oligohydramnios linked with hypoplastic lungs
B. Polycystic kidneys linked to tracheoesophageal fistula
C. Polyhydramnios
D. Renal agenesis linked to insufficient surfactant
E. Urethral obstruction linked to ectopic viscera - answer- A. There is some evidence
that oligohydramnios is linked to hypoplastic lungs. This is apparently not a genetic
link but rather related to the importance of adequate amniotic fluid in normal lung
development. GAS 167, 373; N 208; McM 199
A 4-year-old male child is admitted to the hospital with severe vomiting. Radiologic
examination and history taking reveals that the boy suffers from an annular
pancreas. Which of the following structures is most typically obstructed by this
condition?
A. Pylorus of the stomach
B. First part of the duodenum
C. Second part of the duodenum
D. Third part of the duodenum
E. Jejunum - answer- C. In normal pancreatic development a bifid ventral pancreatic
bud rotates around the dorsal side of the gut tube and fuses with the dorsal
pancreatic bud. Rarely, a portion of the ventral bud rotates around the ventral side of
the gut tube, resulting in an annular pancreas. The portion of the gut tube is the
same where the main pancreatic duct enters the second part of the duodenum
(along with the common bile duct). The incidence of annular pancreas is about 1 in
7000. GAS 336; N 281; McM 235
A 3-year-old male child is admitted to the pediatric clinic. Diagnosis reveals that the
intermediate portion of the processus vaginalis is not obliterated. Which of the
following conditions will most likely result from this?
A. Hypospadias
B. Sterility
C. Congenital hydrocele
D. Ectopic testis
,E. Epispadias - answer- C. The distal portion of the processus vaginalis contributes
to the tunica vaginalis that is related to the testis. If an intermediate portion of the
processus vaginalis persists, it often fills with fluid, creating a hydrocele. If the entire
processus vaginalis persists, the patient is likely to develop a congenital inguinal
hernia. GAS 269; N 365; McM 265, 266
Testicles are absent from the scrotum of a 1-year-old male admitted to the pediatric
clinic. The pediatrician examined the infant and palpated the testes in the inguinal
canal. Which of the following terms is used to describe this condition?
A. Pseudohermaphroditism
B. True hermaphroditism
C. Cryptorchism
D. Congenital adrenal hyperplasia
E. Chordee - answer- C. Cryptorchism, often called an undescended testis, is the
result of incomplete migration of the gonad from the abdomen to a location in the
scrotum where it is exposed to temperatures slightly lower than core body
temperature. This is important for spermatogenesis and testicular function. A testis
that cannot be surgically relocated into the scrotum is usually removed because it
would otherwise be prone to develop testicular cancer. GAS 293; N 364; McM 265,
266
A 28-year-old woman who is 8 months pregnant goes to the outpatient clinic for her
prenatal checkup. Ultrasound examination of the fetus reveals gastroschisis, with
herniation of the small bowel into the amniotic cavity. Failure of proper formation of
which of the following structure(s) has resulted in this condition?
A. Head fold
B. Tail fold
C. Neural folds
D. Lateral folds
E. Amnion - answer- D. The lateral folds are key structures in forming the muscular
portion of the anterior abdominal wall. Failure of the lateral folds can cause a minor
defect, such as an umbilical hernia, or a major defect, such as gastroschisis. GAS
265, 311; N 247; McM 222
Rotation of the stomach during development results in movement of the left vagus
nerve from its original position. Through approximately how many degrees of rotation
does the nerve move, and what is its final position?
A. 90 degrees to become the anterior vagal trunk
B. 90 degrees to become the posterior vagal trunk
C. 270 degrees to become the anterior vagal trunk
D. 270 degrees to become the posterior vagal trunk
E. 180 degrees to become the right vagal trunk - answer- A. Rotation of the gut tube
is a major event in the development of the gastrointestinal system. Parts of the tube
rotate 270 degrees, but the proximal foregut, specifically that portion that forms the
esophagus, rotates only 90 degrees. Looking from below (the standard CT or MRI
view), this rotation is counterclockwise. This brings the left vagus nerve onto the
anterior surface of the esophagus as it passes through the thorax. GAS 265, 363-
364; N 263; McM 241, 257
, A newborn baby was diagnosed with eventration of the diaphragm, wherein one half
of the diaphragm ascends into the thorax during inspiration, but the other half
contracts normally. What is the most likely cause of this condition?
A. Absence of a pleuropericardial fold
B. Absence of musculature in one half of the diaphragm
C. Failure of migration of the diaphragm
D. Failure of development of the septum transversum
E. Absence of a pleuroperitoneal fold - answer- B. The diaphragm develops from
several components. Initially, the septum transversum (which will become the central
tendon) forms in the cervical region, gaining innervation from C3, C4, and C5. Later,
myoblasts migrate in from the body wall to form the muscular part of the diaphragm,
often considered to be two bilateral hemidiaphragms. These muscles are innervated
by the phrenic nerves that are derived from C3, C4, and C5. Eventration of the
diaphragm occurs when one muscular hemidiaphragm fails to develop. With positive
pressure in the abdominal cavity, and low or negative pressure in the thoracic cavity,
abdominal organs are pushed into the thorax. The pleuroperitoneal folds contribute
to a portion of the diaphragm posteriorly. GAS 371; N 191, 192; McM 213, 260
A 2-day-old newborn male is cyanotic after attempts to swallow milk result in
collection of the milk in his mouth. After 2 days he develops aspiration pneumonia. A
tracheoesophageal fistula is suspected. Which of the following structures has most
likely failed to develop properly?
A. Esophagus
B. Trachea
C. Tongue
D. Tracheoesophageal septum
E. Pharynx - answer- D. The tracheoesophageal septum is the downgrowth that
separates the ventral wall of the foregut (esophagus) from the laryngotracheal tube.
The presence of a fistula would result in passage of fluid from the esophagus into the
trachea and could cause aspiration pneumonia. If the esophagus did not develop
correctly, as in esophageal atresia, it would end as a blind tube. This kind of defect,
although associated with tracheoesophageal fistula, is not the result of an opening
into the trachea, and pneumonia would not result. Abnormal tracheal development
can be associated with tracheoesophageal fistula, therefore, but it is not the direct
cause of it. Abnormal tongue development does not result in a tracheoesophageal
fistula. Abnormal development of the pharynx is not associated with a
tracheoesophageal fistula. GAS 172; N 230; McM 196
A 3-day-old newborn male has difficulties in breathing. A computed tomography (CT)
scan of his chest and abdomen reveals the absence of the central tendon of the
diaphragm. Which of the following structures most likely failed to develop properly?
A. Pleuroperitoneal folds
B. Pleuropericardial folds
C. Septum transversum
D. Cervical myotomes
E. Dorsal mesentery of the esophagus - answer- C. The septum transversum forms
the central tendon of the diaphragm. The pleuroperitoneal folds form the
posterolateral part of the diaphragm. The pleuropericardial folds separate the
pericardial cavity from the pleural cavity and form the fibrous pericardium. The
cervical myotomes form the musculature of the diaphragm. The dorsal part of the
