LEC 20: Introduction to Radiographic Anatomy Thoracic Imagining Flashcards Preview

STRUCTURES - WEEK 2 > LEC 20: Introduction to Radiographic Anatomy Thoracic Imagining > Flashcards

Flashcards in LEC 20: Introduction to Radiographic Anatomy Thoracic Imagining Deck (30):

Plain radiograph

x-rays pass through tissues, based on density, and are detected on other side (image)

  • (radiation!)
  • 2-D project of 3-D object
  • orthogonal projects can help localize objects and identify pathology




moving/continuous x-rays often with contrast agent (radiation!)


CT (computed tomography)

similar to radiographs but the x-rays pass through the body in "all" directions (360 degrees) from a rotating source and are detected, used to generate slices through the tissues

  • radiation!
  • imagine walking into patient's room and viewing slices from the foot of bed to the head



When are x-ray, fluoroscopy, and CT ill-advisded


  • developing structures in first trimester are at increased risk of mutogenesis
  • at end of pregnancy, fetuses that get irradiated have increased risk of childhood cancer (leukemia)



CT coronary angiography (CTA)

a computerized tomography (CT) coronary angiogram is an imaging test that looks at the arteries that supply your heart with blood

  • radiation!
  • less invasive than traditional coronary angiogram



MRI (magnetic resonance imaging)

uses body's intrinsic magnetic properties to create images; spinning water hydrogen proton is a mini magnet in a larger magnet

  • energy (RF pulse) sent in and signal comes out to produce image
  • no radiation!
  • no metal, not good for people with claustrophobia



uses high frequency sound waves; different tissues reflect back more or less sound waves, detected by a hand held transducer to generate images

  • portable, "real time" information
  • no radiation!


Density principle

  • bone/metal = white
  • soft tissue = light gray
  • fat = darker gray
  • air = black


How is the anatomy of the thoracic cavity divided

1. Pleural cavities

2. Mediastinum




Contents of the pleural cavities

  • pleura = made up of flat layer of mesothelial cells and supporting tissues
  • lungs = respiratory organs



2 layers:

1. parietal layer = lines inner surface of chest cavity

2. visceral layer = covers surfaces of the lungs

Parietal and visceral layers merge at the Hila of the lungs where vessels and airways pass in/out


Hila of the lungs

Where parietal and visceral layers of pleura merge; Hila is where vessels and airways pass in/out


Costodiaphragmatic recesses

area of pleural space where there is NO visceral pleura (or lung) between 2 parietal layers

  • fluid accumulates here first
  • many recesses in pleura
  • costodiaphragmatic recess is the largest
  • potential space



What is the motion of diaphragm when breathing in

Diaphragm moves down; creates negative interthoracic pressure so air will be sucked in


Pleural effusion

excess fluid builds up around the lung in pleural space (between visceral and parietal layers)

  • hydrothorax (serous fluid)
  • hemothorax (blood)
  • chylothorax (chyle)
  • pneumothorax (air)
  • pyothorax (pus)



pleural plaques due to asbestos exposure



  • organs of respiration (gas exchange)
  • fill the pleural cavities surounded by visceral (lung facing) and parietal (body wall facing) pleura
  • straddle mediastinum
  • divided into lobes
    • lobes divided into bronchopulmonary segments
    • areas of the lung supplied by segmental bronchus and pulmonary artery branches


left lung

  • one fissure (oblique/major): divides lung into 2 lobes (upper and lower)
  • left mainstream bronchus enters lung and then branches into upper and lower lobe branches



right lung

  • two fissures (oblique and horizontal) divide it into 3 lobes (upper/middle/lower)
  • right mainstem bronchus branches outside the lung into upper lobe branch and then branches inside lung


Lungs have dual blood supply

  • pulmonary arteries
    • R atrium-->R ventricle-->main pulmonary artery-->R/L pulmonary arteries (deoxygenated blood)
  • bronchial arteries
    • blood comes from aorta or its branches (oxygenated blood)



Divisions of Mediastinum

  • can be divided into inferior mediastinum and superior mediastinum
  • inferior mediastinum
    • anterior
    • posterior
    • middle
      • origins of great vessels
      • heart
      • pericardium


Contents of Mediastinum

  • thymus (immune system, site of T-cell maturation)
  • heart in pericardial sac
  • major vessels
  • trachea
  • esophagus
  • nerves and lymphatics


Position of heart in chest

  • NOT straight up and down in chest
  • apex points down, forward, to left
  • base sits over diaphragm with right more forward than left
  • major vessels enter/exit posteriorly at base


Right pump of the heart

carries deoxygenated blood from body to lungs

SVC/IVC-->R atrium-->R ventricle-->pulmonary arteries



Left pump of the heart

carries oxygenated blood from lungs

lungs-->pulmonary veins-->L atrium-->L ventricle-->aorta




congenital birth defect where heart is pointed toward right side of chest (instead of normally pointing to the left)


What heart margins are visible in chest x-ray (right side)

  • SVC
  • R atrium
  • IVC
  • NOT R ventricle; heart is rotated


What heart margins are visible in chest x-ray (left side)

  • Aortic arch
  • pulmonary trunk
  • L atrium
  • L ventricle



Superior mediastinum

  • R/L brachiocephalic veins
  • thoracic aorta and major branches
  • SVC
  • Trachea
  • Esophagus
  • Thymus
  • Phrenic and vagus nerves
  • Left recurrent laryngeal nerve (passes under arch)


SVC syndrome

group of symptoms caused by obstruction of the superior vena cava (a short, wide vessel carrying circulating blood into the heart)

  • 90% of SVC syndrome caused by cancer