Ch. 6 Thorax Flashcards
Where should the central axis of the XR beam be centred for a lateral projection of the thorax?
Just caudal (or approx. 1 inch caudal to the scapula)
How can you tell that a lateral projection is perfectly positioned?
The most dorsal aspects of the caudal ribs are superimposed.
Dorsally located pulmonary lesions are usually more conspicuous in ___ view, and ventrally located lesions (including accessory lobe lesions) in the ____ view.
dorsal - DV
ventral + accessory - VD
In which lateral view do the crura diverge dorsally?
left
in left lateral, which crus is more cranial and why?
left crus is more cranial (they diverge dorsally) because of pressure from abdominal organs, and because of decreased lung aeration, in the dependent left lung
Is there more or less heart to sternal contact in the left lateral view, compared with the right lateral view?
Less
Which lobe artery/vein pair is typically easiest to identify in lateral? In which lateral view is this the case and where are they located? (dorsal or ventral)?
The right cranial lobe or treat/vein pair is the easiest identify in the left lateral view being the most ventral, the cranial lobe vasculature.
which 3 things indicate the laterality?
LL; look at crura divergence, pyloric gas and CVC entrance
In a left lateral view, the vessels superimposed over the heart are typically the ________ lobe artery/vein.
right middle
What is the pathology rises phenomenon?
Not only do normal structures in the dependent lung become displaced dorsally, but also pulmonary lesions. This occurs in both left and right lateral views and is referred to as the down pathology rises phenomenon
The normal cardiac shift to the ____ in the __ view is commonly misinterpreted as cardiomegaly
left, DV
The caudal lobar pulmonary vessels are more conspicuous in the ___ view.
DV; perpendicular (less distortion) and less atelectasis
Why would assessment of the right caudal lobe pulmonary vein and/or caudal vena cava be difficult?
because they are superimposed
The caudal lobar arteries/veins should be the diameter of which rib, in VD or DV?
– what is the upper limit?
9th, up to 1.2x
(image shows superimposition of the R caudal and CVC)
Which shape is the heart in VD, compared to DV?
more narrow and elongated
also more centrally located, and more space between caudal heart and diaphragm
costchondral mineralisation
costchondral mineralisation
how many sternebrae are there, and what is the 1st and last called?
8; manubrium and xiphoid process
morphological abnormalities are common for which sternebra?
xiphoid process - e.g. hypoplasia or absence
uncommon for manubrium
Xiphoid process abnormalities are associated with _____.
pectus excavatum
Pectus excavatum is associated with abnormalities of which sternebra?
xiphoid process; there is often variable mineralisation that can be confused with an aggressive lesion. Proliferative degenerative remodelling can also occur.
Is pectus excavatum always clinically significant?
It is often not associated with any clinically significant complications.
Why can the mediastinum contain unilateral pleural disease?
because it is fenestrated
how does the mediastinum communicate with the neck, and the retroperitoneal space?
neck - fascial planes
retroperitoneal space - aortic hiatus
what are mediastinal reflections?
areas where the mediastinum deviates from midline:
- cranioventral
- caudoventral
- plica vena cava
where is the cranioventral mediastinal reflection?
between the right cranial and cranial left cranial lung lobe
what is the most cranial pulmonary tissue? i.e. which lobe
cranial left cranial lobe
which lung lobe crosses the midline?
- the left cranial crosses to the right, at the cranial thoracic inlet
just caudal to this,
- the right cranial crosses to the left
(between them is the cranioventral mediastinal reflection)
Which vessels lie in the cranioventral mediastial reflection?
internal thoracic a. & v.
what are the borders of the caudoventral mediastinal reflection?
l caudal lobe, accessory lone