This document discusses diaphragmatic hernias and anatomy. It describes: 1) The anatomy of the diaphragm including its muscular components and potential weaknesses. 2) The different types of congenital diaphragmatic hernias including Bochdalek and Morgagni hernias. 3) Acquired diaphragmatic hernias such as hiatal hernias and traumatic ruptures of the diaphragm. 4) Imaging features of diaphragmatic hernias and variants seen on radiography, CT, MRI and ultrasound. Direct and indirect signs of rupture are outlined.

1. Diaphragmatic Hernia
Thorsang Chayovan
Chaiyapongse Tangsittitum
PGY2 Radiology

2. Outline
• Anatomy
• Embryology
• Anatomic variants
• Diaphragmatic hernias
– Congenital: Bochdalek and Morgagni hernias, along
with diaphragmatic eventration, typically originate in
utero from developmental weaknesses or defects in
the diaphragm
– Acquired: Hiatal hernias and traumatic diaphragmatic
rupture

3. Diaphragm: Anatomy
• Musculotendinous dome-shaped structure that
demarcates pleural and peritoneal cavities.
• The 3 muscular components converge into the
central tendon
– Pars lumbaris
– Pars costalis
– Pars sternalis

6. Diaphragm: Anatomy
• Gaps between muscle groups: pleura,
peritoneum, and 2 fascial layers → potential
weakness

7. A, Aortic hiatus; B, Bochdalek space; CT, central tendon; E, esophageal hiatus; IVC, caval hiatus; M, Morgagni
space; L, Larrey space; PC, pars costalis; PL, pars lumbaris; PS, pars sternalis.

10. Diaphragm: Anatomy
• Innervation:
– Bilateral phrenic nerves (C3–C5)
– Lower intercostal nerves
• Arterial supply
– Internal thoracic artery
• Pericardiophrenic aa.
• Musculophrenic aa.
– Inferior phrenic arteries

11. Diaphragm: Embryology

12. Imaging of diaphragm
– Anatomic: All modalities
– Functional: Fluoroscopy, US, and MR fluoroscopy

13. Imaging of diaphragm: Radiography
• Normal
– Upper aspect: can see on frontal and lateral views
– Lower border: blend with the soft tissues
• Frontal
– Rt. dome: anterior sixth rib
– Lt. dome: usually 1 ICS lower than Rt.
• Lateral
– Anterior part of Lt. dome: obscured by cardiac shadow
– Rt. Hemidiaphragm: entirely seen

15. Imaging of diaphragm: Ultrasonography
• Thick echogenic line
• Portions of both domes can be seen together
on an oblique transverse subxiphoid view
obtained at midline: real-time assessment of
the movement
• Individual domes can be assessed in
parasagittal or coronal planes

17. Imaging of diaphragm: CT and MRI
• Excellent modalities(multiplanar capability
and soft-tissue resolution)
• Multiplanar imaging: easier understanding of the
orientation of anatomy and pathology
• MRI: excellent soft-tissue resolution
– Low signal intensity compared to skeletal muscles
in all sequences

19. Imaging of diaphragm: CT and MRI
• Small children: crura are larger relative to
body size and T12 vertebral body diameter +
more chance of nodularity

21. Anatomic Variations
• Diaphragmatic slip
• Nodular crura
• Prominent (hypertrophic) median and lateral
arcuate ligaments

22. Anatomic Variations: Diaphragmatic slip
• Common anatomic variant
• Folds or bundles of muscle run obliquely along
inferior surface of diaphragm → fold or strip of
muscle bundle protruding from inferior
surface of diaphragm ± smooth indentation of
liver or spleen
• Unilateral or bilateral, single or multiple
• Mimic mass, peritoneal implant, or LN

23. Anatomic Variations: Diaphragmatic slip
• CT:
– Hypodense bands running obliquely along the inner
surface of the diaphragm
– Scalloped appearance diaphragm
– Diaphragm tends to bulge upward on either side of slips:
mimic diaphragmatic hernia or weakness
• USG:
– Echogenic(mimic intrahepatic mass)
– Deep inspiration increased prominence of the slips.
– Care must be taken to distinguish this normal anatomic
variant from the array of true diaphragmatic defects.

26. Anatomic Variations: Nodular crura
• Hypertrophy or nodularity, especially in small
children and during deep inspiration

27. Anatomic Variations: Prominent
median and lateral arcuate ligaments
• 10%–24% of people
• Median arcuate ligament cross over proximal
portion of celiac trunk → unique indentation
• Some have compressive symptoms of celiac a:
postprandial epigastric pain and weight
loss(median arcuate ligament syndrome or
celiac artery compression syndrome)

28. Anatomic Variations: Prominent
median and lateral arcuate ligaments
• CT or CTA
– Hooked appearance and narrowing of celiac trunk
– Rarely, lateral arcuate ligaments appears nodular:
mimic lymph nodes and peritoneal deposits

30. Congenital and Developemental
Pathologic Conditions
• Congenital diaphragmatic hernia
• Eventration
• Aplasia/hypoplasia/accessory diaphragm
• Rarely, diaphragmatic abnormalities may be
seen in association with congenital pulmonary
venolobar syndrome, heterotaxy, and situs
inversus

31. Accessory Diaphragm
• Fibromuscular membrane fused anteriorly
with the diaphragm and coursing
posterosuperiorly to join posterior chest wall
• May associated with other congenital
anomalies: extralobar pulmonary
sequestration, lobar agenesis or aplasia, and
unilateral single pulmonary vein

32. Accessory Diaphragm
• Part of lung which trapped below accessory
diaphragm was supplied by pulmonary vessels
and bronchi that run through hole in
accessory diaphragm

33. Accessory Diaphragm

34. Eventration
• Abnormal elevation of an intact
hemidiaphragm into chest cavity
• Thought to be due to congenital absence of
muscle fibers in region of eventration
(however, lack of thinning fibers there)
• Other causes: focal dyskinesia and weakness
from ischemia, infarct, or neuromuscular
dysfunction

35. • Most common location: anteromedial aspect
of Rt. Hemidiaphragm(usually occupied by
part of liver)

38. • DDx
– Morgagni hernia
– pericardial cyst
– paraesophageal hernia
– bronchogenic cyst
– Tumor

39. • Complete eventration of a hemidiaphragm:
more common in males and typically occurs
on the left side

40. Diaphragmatic
Hernia

41. Bochdalek Hernia
• Posterolateral defect
• Between pars costalis
and pars sternalis
• Malformation of the
pleuroperitoneal fold
• Failure of the
pleuroperitoneal fold
and septum
transversum to fuse
properly with intercostal
muscles

42. Bochdalek Hernia
• The most common CDH
• Mostly diagnosed at antenatal US or manifest
at birth with respiratory distress
• 80% occurs on the left side

43. Bochdalek Hernia
• Asymptomatic
• Newborn: respiratory failure
• Age > 1 month: gastrointestinal symptoms
– Rarely bowel incarceration, strangulation,
perforation, or shock.
• Hernias in this location of natural diaphragmatic
weakness may also be acquired or exacerbated
through trauma or physical exertion.

44. Bochdalek Hernia: imaging
• Discontinuity of the posterior or posteromedial
diaphragm
• Protrusion of
– Peritoneal or retroperitoneal fat through the defect
– Less commonly, colon, small bowel, liver, spleen, or kidney
herniation
• DDx in radiograph:
– Lipoma, lung or diaphragmatic tumors, neurogenic tumor,
intrathoracic kidney, or pulmonary sequestration.
• CT: the homogeneous fatty composition + discontinuity
of the diaphragm

53. Morgagni Hernia
• An anterior opening
• Sternum medially
(pars sternalis)
• Eighth rib laterally
(pars costalis)
• Failure of fusion
between the
transverse septum and
the lateral body wall

54. Morgagni Hernia
• 90% are right-sided
• Mostly detected in older children and adults
– Incidental
– Manifest as pulmonary infection or GI obstruction
• Anterior herniation of bowel loops on a lateral
chest radiograph

55. Morgagni Hernia
• Neonates: liver, bowel, or stomach
• Older children: bowel alone
• Adults: omentum is common, and only rarely with
bowel, stomach, or liver
– Women (61%)--average age of 58 years
– Men--bimodal pattern of presentation, with a first peak at
31-35 years and 50-60 years
• If bilateral  associated with pericardial defects and
chromosomal anomalies
• Predisposing conditions ~ abdominal hernias
– pregnancy, trauma, obesity, chronic constipation, and
chronic cough

56. Morgagni Hernia: imaging
• Radiograph: a fatty mass in the right
cardiophrenic angle
– DDx prominent epicardial fat pad, other fat-containing
masses (lipoma, teratoma, thymoma, thymolipoma,
or liposarcoma)
• Displaced curvilinear omental vessels
– Within the “mass”
– Coursing across the diaphragmatic defect
Best appreciated with coronally reformatted CT or MR

60. Morgagni Hernia
• Morgagni hernia may occur as a component of the
pentalogy of Cantrell
1. Omphalocoele
2. Ectopia cordis (abnormal location of heart)
3. Diaphragmatic defect
4. Pericardial defect or sternal cleft
5. Cardiovascular malformations
– ventricular septal defect (VSD)
– atrial septal defect (ASD)
– tetralogy of Fallot
– left ventricular diverticulum

61. Congenital diaphragmatic hernias
• Physiologic abnormalities of the lungs
• Pulmonary hypoplasia
• Pulmonary hypertension

63. Congenital diaphragmatic hernias
• DDx
– Bronchopulmonary foregut malformation
– Sequestration
– Congenital cystic adenomatoid malformation
– Pulmonary agenesis or hypoplasia

64. Acquired Diaphragmatic Hernias
• Trauma or degeneration
• Hiatal hernia
• Traumatic diaphragmatic rupture

65. Hiatal hernia
• 50% of diaphragmatic hernia
• Acquired: mostly
• Congenital

66. Hiatal Hernia
• Esophageal hiatus
• Due to stretching,
weakening, or tearing
of the
phrenoesophageal mb
• Upward dislocation of
the esophagus and
stomach
• 2 types
– Sliding-type
– Paraesophageal

67. Hiatal Hernia
• Incidence increases with age
• Most are asymptomatic
• About 1/5 of patients with a hiatal hernia have
associated gastro-esophageal reflux (only in
sliding hernia)

68. Sliding hiatal hernia: Complications
• Best characterized
on esophagogram
• Schatzki’s B ring
demarcates the GE
junction
displaced above
the diaphragm

69. Sliding hiatal hernia: Complications
• Large incarcerated hiatal hernias may slowly
weep blood
– Iron deficiency anemia
• Peptic esophagitis from reflux
• Discrete marginal ulcers
• Strictures

70. Sliding hiatal hernia: Complications
• Common association with Barrett’s esophagus
– Columnar epithelium lining the esophagus
– Acquired condition related to chronic GERD
• Patients with a Barrett’s esophagus can develop
– Ulcer
– Stricture
– Malignancy
• 30-40 times higher risk of esophageal adenocarcinoma than
the general population

71. Paraesophageal hiatal hernia
• All or part of the stomach enters the thorax
through a defect in the phrenoesophageal
membrane
• Alongside the esophagus
• GE junction remains in the peritoneal cavity
• Not associated with GE reflux
• Usually incarcerated
• Higher risk of gastric volvulus

73. Larger hiatal hernias
• Radiograph: a gastric air bubble above the
diaphragm
– in the midline on frontal view
– posterior to the heart on lateral view
• CT or MR: gastric folds pass through the hiatus
• EG junction above the diaphragm: sliding
• EG junction under the diaphragm:
paraesophageal type

74. Other conditions
• Intrathoracic stomach
– Cardia may still be subdiaphragmatic
– Greater curvature may be on left or right side
• Congenitally short esophagus (rare)
– Short, straight esophagus
– Stomach in thorax
– GE reflux

77. Hiatal hernia
• Acquired: mostly
• Congenital
– A delay in the descent of the stomach from the
chest
– Children with paraesophageal hernia
• Gastrosplenic and gastrocolic ligaments are often
absent in
• Prone to organoaxial volvulus of the stomach and
colonic herniation

78. Traumatic Diaphragmatic Rupture
• Blunt injury
– Trauma
– Pregnancy or labor
– Spontaneously
The defect size is typically greater than 10 cm.
• Penetrating injury
Usually less than 2 cm in length

79. Traumatic Diaphragmatic Rupture
Lateral impacts
• An AP elongation
• Rupture of the diaphragm
or insertion detachment
Frontal impacts
• Increase intra-abdominal
pressure abruptly
• Transmitting the impact to
the pillars of the diaphragm
• RuptureRib fracture
• Rupture of the diaphragmatic insertion
• Tears are most likely to occur at sites of structural
weakness
• within the central tendon
• junction of muscle and central tendon.

81. Traumatic Diaphragmatic Rupture
• Blunt traumatic diaphragmatic rupture is more
common on the left side
– The right hemidiaphragm may be relatively
protected from injury due to buffering by the liver
– Delayed presentation--more common on the right
side, can lead to complications such as bowel
strangulation
• Indicative of a high impact and is associated
with other severe injuries

82. Traumatic Diaphragmatic Rupture
Direct signs
• Abrupt loss of diaphragm
continuity
• No visualization of the
hemidiaphragm
• Dangling diaphragm sign
Indrect signs
• Protrusion of abdominal
content into the pleural
space
• Collar sign
• Dependent viscera sign
• Hump sign
• Elevated abdominal organs

83. Direct signs of diaphragmatic rupture
• Abrupt loss of diaphragm continuity
– Associated with a thickening of the free edge due
to retraction or hemorrhage
– Spotted when the defect is small or in contact
with the abdominal fat or the aerated lung.
– This sign has a sensitivity ranging from 17 to 80%,
with a specificity of 90 to 100%.

85. Direct signs of diaphragmatic rupture
• No visualization of the hemidiaphragm
– Large hernial defects
– This sign has a specificity of 91% and a sensitivity
ranging from 18 to 43%

87. Direct signs of diaphragmatic rupture
• Dangling diaphragm sign
– A comma-shaped curving of the free edge at the
rupture site
– This sign has a specificity of 98% and a sensitivity
of 54%

89. Traumatic Diaphragmatic Rupture
Direct signs
• Abrupt loss of diaphragm
continuity
• No visualization of the
hemidiaphragm
• Dangling diaphragm sign
Indirect signs
• Protrusion of abdominal
content into the pleural
space
• Collar sign
• Dependent viscera sign
• Hump sign
• Elevated abdominal organs

90. Indirect signs of diaphragmatic
rupture
• Protrusion of abdominal organs or peritoneal
fat into the pleural space
– This sign has a specificity of 98% and a sensitivity
ranging from 50 to 95%

92. Indirect signs of diaphragmatic
rupture
• Collar sign
– Secondary to the
compression of a
herniated structure at
the site of rupture
– DDx diaphragmatic
displacement, hepatic
lacerations or
artifacts caused by
breathing

95. Indirect signs of diaphragmatic
rupture
• Dependent viscera sign
– The herniated abdominal organ in direct contact with
the posterior thoracic wall
– Spleen, liver, stomach and intestinal loops suspended
above the diaphragm and separated from the
posterior thoracic wall by the lung parenchyma.
– Herniated abdominal viscera to slightly drop, due to
gravity, into contact with the posterior thoracic wall.
– This sign has a specificity ranging from 54 to 90% and
a sensitivity ranging from 98 to 100%.

97. Indirect signs of diaphragmatic
rupture
• Hump sign
– A consequence of hepatic herniation
– hypodense band in the hepatic parenchyma
between the torn diaphragm edges
(compression-driven hypoperfusion condition)

99. Indirect signs of diaphragmatic
rupture
• Elevated abdominal organs
– Contralateral hemidiaphragm to be at a lower
level
– Suggestive when displacement > 5 cm in the right
side and 4 cm in the left side is found
– DDx simple anatomical variation, eventration,
paralysis of the diaphragm, or presence of
subpulmonary fluid.

106. Summary
• Anatomic variants
– Diaphragmatic slip
– Nodular crura
– Prominent (hypertrophic) median and lateral
arcuate ligaments

107. Summary
• Diaphragmatic hernias
– Congenital: Bochdalek and Morgagni hernia
– Acquired: Hiatal hernia and traumatic

108. Diaphragmatic
Hernia

109. References
• Chavhan, G. B., P. S. Babyn, R. A. Cohen, and J. C. Langer.
"Multimodality Imaging of the Pediatric Diaphragm: Anatomy and
Pathologic Conditions." Radiographics 30.7 (2010): 1797-817. Web.
• Taylor, George A., Omolola M. Atalabi, and Judy A. Estroff. "Imaging
of Congenital Diaphragmatic Hernias." Pediatric Radiology 39.1
(2009): 1-16. Web.
• Gimena A. R., Jorge A. C., and Liliana A. “Traumatic Diaphragmatic
Hernia: Case Series and Topic Review.” Colomb Radiol. 2012; 23(4):
3579-86. Web.
• Desir, Amandine, and Benoît Ghaye. "CT of Blunt Diaphragmatic
Rupture." RadioGraphics 32.2 (2012): 477-98. Web.
• "Hiatal Hernia." LearningRadiology, n.d. Web. 29 Mar. 2015.