Chapter 21 - Body Cavities

Question 1

A congenital diaphragmatic hernia may
result from failure of the

(A) septum transversum to develop
(B) pleuroperitoneal membranes to fuse in a
normal fashion
(C) pleuropericardial membrane to develop
completely
(D) dorsal mesentery of the esophagus to
develop
(E) body wall to form the peripheral part of
the diaphragm

Answer 1

B. Pleuroperitoneal membranes to fuse in a normal fashion

The formation of the diaphragm occurs through the fusion of tissue from four different
sources. The pleuroperitoneal membranes normally fuse with the three other components
during week 6 of development. Abnormal development or fusion of one or both of the
pleuroperitoneal membranes causes a patent opening between the thorax and abdomen
through which abdominal viscera may herniate.

Question 2

A congenital diaphragmatic hernia most
commonly occurs

(A) on the right anteromedial side
(B) on the right posterolateral side
(C) on the left anteromedial side
(D) on the left posterolateral side
(E) anywhere on the left side

Answer 2

D. On the left posterolateral side

Congenital diaphragmatic hernias occur most commonly on the left posterolateral side.
The pleuroperitoneal membrane on the right side closes before the left for reasons that are
not clear. Consequently, the patency on the left side remains unclosed for a longer time. The
portion of the diaphragm formed by the pleuroperitoneal membrane in the newborn is
located posterolateral.

Question 3

A congenital diaphragmatic hernia is usually
life threatening because it is associated
with

(A) pulmonary hypoplasia
(B) pulmonary hyperplasia
(C) physiological umbilical hernia
(D) liver hypoplasia
(E) liver agenesis

Answer 3

A. Pulmonary Hypoplasia

The herniation of abdominal contents into the pleural cavity compresses the developing
lung bud, resulting in pulmonary hypoplasia. Lung development on the ipsilateral (left)
side of the herniation is most commonly affected, but lung development on the contralateral
(right) side can also be compromised. The lungs may achieve normal size and function
after surgical reduction of the hernia and repair of the diaphragm. However, mortality is
high due to pulmonary hypoplasia.

Question 4

An 8-day-old boy presents with a history
of complete loss of breath at times and of
turning blue on a number of occasions. If
the baby is placed in an upright or sitting
position, his breathing improves. Physical
examination reveals an unusually flat stomach
when the newborn is lying down;
auscultation demonstrates no breath sounds
on the left side of the thorax. What is the
diagnosis?

(A) Physiological umbilical herniation
(B) Esophageal hiatal hernia
(C) Tetralogy of Fallot
(D) Congenital diaphragmatic hernia
(E) Tricuspid atresia

Answer 4

D. Congenital diaphragmatic hernia

Loss of breath and cyanosis result from pulmonary hypoplasia associated with congenital
diaphragmatic hernia. Placing the baby in an upright position will reduce the hernia
somewhat and ease the pressure on the lungs, thereby increasing the baby’s comfort. The
baby’s stomach is flat (instead of the plump belly of a normal newborn) because the
abdominal viscera have herniated into the thorax. Auscultation reveals no breath sounds
on the left side because of pulmonary hypoplasia.

Question 5

During week 4, the developing diaphragm
is located at

(A) C3, C4, C5
(B) T3, T4, T5
(C) T8, T9, T10
(D) L1, L2, L3
(E) L4, L5, L6

Answer 5

A. C3, C4, C5

Although it may seem unusual, the adult diaphragm has its embryological beginning at
the cervical level (C3, C4, C5). Nerve roots from C3, C4, and C5 enter the developing
diaphragm, bringing both motor and sensory innervation. With the subsequent rapid
growth of the neural tube, there is an apparent descent of the diaphragm to its adult levels
(thoracic and lumbar). However, the diaphragm retains its innervation from C3, C4, and C5,
which explains the unusually long phrenic nerves.

Question 6

An apparently healthy newborn with a
hardy appetite has begun feedings with formula.
When she is laid down in the crib after
feeding, she experiences projectile vomiting.
Which of the following conditions is a probable
cause of this vomiting?

(A) Physiological umbilical herniation
(B) Esophageal hiatal hernia
(C) Tetralogy of Fallot
(D) Congenital diaphragmatic hernia
(E) Tracheoesophageal fistula

Answer 6

B. Esophageal hiatal hernia

An esophageal hiatal hernia is a herniation of the stomach through the esophageal hiatus
into the pleural cavity. This compromises the esophagogastric sphincter so that
stomach contents can easily reflux into the esophagus. The combination of a full stomach
after feeding and lying down in the crib will cause vomiting in this newborn.