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Flashcards in Thoracic wall and diaphragm Deck (16):

Diaphragm anatomy

  • Musculotendinous partition
  • Major muscle contributor to respiration
  • Large surface area assists in the lymphatic drainage of the abdomen
  • Attaches at the ventral aspect of L3-4
  • 2 crura and large capula (body)
  • 3 openings which allow aorta (hiatus), vena cava (foramen), nerves, esophagus (hiatus), thoracic duct, and azygos


Radiographic anatomy

  • Diaphagm is uncommonly detected as a separate radiographic entity
  • To be detected it requires that adjacent structures must be of dif. opacities
  • More commonly only the most ventral portion is detected as it is adjacent to the falciform ligament
  • Several normal anatomical variations are poss.
    • Cats do not follow the rules
    • Many reasons: breed, age, obesity, respiration, gravity, beam/animal positioning

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How are the right and left lateral views different?

What species breaks the rules?

What can cause crus to differ?

  • Right
    • R crus more cranial
    • CVC enters most cranial crus
    • Crus more parallel
  • Left
    • L crus more cranial
    • CVC crosses over cranial crus and enters caudal one
    • Crura are divergent
    • Fundus of stomach caudal to L crus
  • Not reliable in cats (assholes)
  • Obesity and disease might affect crura

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DV and VD views

  • In VD you may detect 1, 2, or 3 dome-shaped structures assoc. w/ the diaphragm
  • Depends on beam centering
  • In DV usually only 1

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Diaphragmatic lesions

  • Hernias
    • Diaphragmatic
      • Acquired
      • Congenital
        • Peritonealpericardial diaphragmatic
        • Hiatal
        • Gastroesophageal intussusception
  • Hernias may be detected incidentally


Diaphragmatic hernias

  • Abdominal viscera protrudes through the diaphragm
  • Most common cause = trauma
  • May/may not result in clinical signs
    • Dyspnea, abdominal pain, vomiting, regurg, muffled heart sounds, weak femoral pulse
    • May have concurrent pleural fluid
  • Rads may be diagnostic
  • Other diagnostic imaging modalities
    • Ultrasound
    • Barium study


Traumatic DH--radiographic signs

  • Abdominal viscera in pleural space
  • Displacement of abdominal structures
  • Displacement of thoracic structures


Congenital abnoramalities: peritonealpericardial diaphragmatic hernia (PPDH)

  • Round cardiac silhouette
  • Heterogenous opacity (fat/gas) of cardiac silhouette
  • Silhouetting of heart and diaphragm
  • Can be assoc. w/ sternal abnormality
  • Usually incidental finding


Congenital abnormalities: hiatal hernia

  • Portion of stomach enters thorax through esophageal hiatus
  • 2 types:
    • Sliding
    • Paraesophageal
  • May be assoc. w/ esophageal reflux
  • Often manifests in patients w/ partial upper airway obstruction
  • Most common to see in L lateral view but not in R or VD
  • May have to give barium to confirm (but usually not due to classic changes in conspicuity with position)


Thoracic wall anatomy

  • Intercostal muscle
  • Fat
  • Nerves
  • Ribs
  • Thoracic vertebrae
  • Blood vessels
  • Skin
  • Parietal pleura
  • Sternebrae
  • Often ignored; critical part of the assessment/evaluation of the thorax


Pitfalls of thoracic wall anatomy

  • Mineralization of cartilaginous portion as dogs age
    • Can be seen early in very young dog
  • Once mineralized (stiff) can form exuberant calcificdations around the costochondral jx
    • Can be confused with tumors, infection or lung nodules


Thorax: radiographic anatomy

  • Pedunculated soft-tissue nodules attached to the skin may appear as nodules in the lung parenchyma
    • Nodules are very distinct
    • May need additional views
    • Can apply contrast to area and retake radiograph


Thoracic congenital abnormalities

  • Changes in number, shape/position of ribs vertebrae, sternebrae are not uncommon
    • Agenesis
    • Hypoplasia
    • Bilateral or unilateral


Thoracic congenital abnormalities: pectus excavatum

  • Mild to severe dorsal placement of the caudal sternebrae
  • Results in reduced size of thoracic cavity
  • Displacement of the heart
  • Occasionally seen in cats, rare in dogs


3 thoracic wall lesions?

  • Trauma 
  • Rib tumors
  • Soft tissue tumors


Thoracic wall masses

Sometimes hard to tell thoracic wall masses from lung masses (intrapulmonary or extrapleural)


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