Chapter 29 - Diaphragm Flashcards
How is diaphragm formed embryologically?
Septum transversum ventrally and by mesentery of foregut and two pleuroperitoneal folds dorsally
What makes up the pars lumbalis?
Where does the pars lumbalis attach?
Right and left crura
L3-L4 vertebral body
What are 3 openings in the diaphragm?
1) aortic hiatus: aorta, azygos, hemiazygos veins, and thoracic duct
2) esophageal hiatus - esophagus and vagus nerve trunks
3) caudal vena cava
Which crura is displaced cranially on a lateral radiograph?
The dependent crura
What do the crura appear like on a right lateral radiograph?
Parallel to each other
CVC goes ‘right’ up to the cranial aspect of the diaphragm
What do the crura appear like on a left lateral radiograph?
V-shaped to each other
CVC ‘leaves’ (l for leaves) the cranial aspect of the diaphragm (the left crus) behind.
What is the differences in the diaphragm appearance between a highly inspiratory vs expiratory lateral radiograph?
Inspiration normally the diaphragm intersects with the spinebetween T11-T13 but may be further caudal.
Inspiration - flattened shape
What can cause cranial displacement of the diaphragm?
obesity, ascites, gastric/intestinal distention, abdominal masses , peritoneal fluid, diaphragmatic paralysis
What does the term ‘tenting of the diaphragm’ refer too?
Attachment sites at muscle attachments to the diaphragm that are seen on VD radiographs - little V shaped structures on cranial aspect of diaphragm.
Due to hyperinflation
Why can the cranial aspect of the duodenum be seen so well, and not the caudal?
Cranial - no border effacement. Air from lung and soft tissue from diaphragm interface
Caudal - border effacement with the liver. Soft tissue on top of soft tissue
What are things that cause superimposition with the cranial aspect of the diaphragm (stuff in the thorax?)
fluid, fat, hernias, mass, pleural inflammation
What will cause caudal displacement of the diaphragm
severe respiratory distress, tension pneumothorax
What types of diaphragmatic hernias are there?
Trumatic Peritoneopericardial Haital Peritoneopleural other congenital diaphragmatic defects
What imaging tests could be done to confirm a diaphragmatic hernia?
barium swallow positive contrast peritoneography positive contrsat pleurography angiocardiography nonselective cardiography CT US
Most common organs to herniate in a traumatic hernia?
liver, small bowel, stomach, spleen, omentum
Radiographic signs seen with a traumatic diaphragmatic hernia?
Abnormal structures in the thorax (homogeneous soft tissue vs bowel loops)
Loss of definition of the diaphragmatic borders
Cranial displacement of abdominal organs
pleural fluid - can mask some of these other signs
What are the congenitally predisposed diaphragmatic hernias?
peritoneopericardial diaphragmatic
hiatal hernias
peritoneopleural
What is PPDH?
Peritoneopericardial diaphragmatic hernia
Abdominal viscera herniates into pericardial sac through a congenital hiatus formed between tendinous portion of diaphragm and pericardial sac
What is presenting complaint of PPDH?
Usually none - incidental findings
Radiographic signs associated with PPDH?
Abdominal organs in the pericardial sac: gas, ingesta, soft tissue opacity
Large, round cardiac silhouette
Communication/lack of distinction between caudal aspect of cardiac silhouette and cranial diaphragm
Dorsal peritoneopericardlal mesothelial remnant in between heart and diaphragm on lateral views
What is a hiatal hernia?
portion of stomach enters the thorax through the esophageal hiatus
What are the 2 types of hiatal hernias?
sliding and paraesophageal
What is a sliding hiatal hernia?
Gastroesophageal sphincter and portion of the stomach herniate into the thorax through the esophageal hiatus
Supposedly associated with esophagitis and GE reflux (not always true - see article about congenital sliding hernias in shar-peis)
What is a paraesophagela hiatal hernia?
Cardiac or cardia and fundus of stomach or other tissue herniates through or alongside the esophageal hiatus and becomes positioned adjacent to the esophagus.
These are usually static
Which type of hernia (or both) are static or temporary?
Static - paraesophageal, PPDH
Temporary - sliding, traumatic
What are hte types of hiatal hernias?
Type I-IV I - sliding II - paraesophageal III - combination of I and II IV - herniation of organ other than stomach, OR gastroesophageal intussusception
Radiographic signs associated with sliding hiatal hernias?
Soft tissue mass adjacent to left diaphragmatic crus Loss of thoracic surface outline Craniald isplacement of gastric cardia Dilated esophagus pneumonia
Esophagram findings of sliding hiatal hernias?
Dilated esophagus
Hypomotile esophagus
Gastroesophageal sphincter within thorax - circumferentially narrowed area of esophagus
GE reflux
What is radiographic appearance of GE intussusception?
large soft tissue mass adjacent to diaphragms with a dilated esophagus.
What nerve innervates the diaphragm
The phrenic nerve
Where does the phrenic nerve originate?
C3,4-5 - keeps the diaphragm alive!
What are causes of diaphragmatic paralysis?
pneumonia, trauma, myopathies, neuropathies, or unidentified
What is best way to confirm diaphragmatic paralysis?
fluoroscopy
what is seen on fluoroscopy with unilateral diaphragmatic paralysis?
unequal movement between the crura
What is seen on fluoroscopy with bilateral diaphragmatic paralysis?
minimal or no diaphragmatic movement
or a paradoxic cranial displacement during inspiration
