3b. Thorax HAL - Worksheet Flashcards
what is the first chamber you will see passing left to right in sagittal
left ventricle
what is the first chamber you will see passing right to left in sagittal
right atrium
what is the last chamber you will see passing front to back in coronal
left atrium
what is the first chamber you will see passing front to back in coronal
right ventricle
do you encounter the atria or the ventricles first when scrolling top to bottom in axial
atria more so than ventricle
what basic architectural feature helps to determine if you are looking at a ventricle or an atrium in an otherwise normal heart
thick muscular wall of the left ventricle
how does the right ventricle compare to the left ventricle morphologically? How is this related to their function
left ventricle has more muscular walls than the right
left ventricle pumps to the rest of the body which is a higher pressure circuit so needs more muscle to pump
Right ventricle only pumps to the lungs which is lower pressure circuit and requires less power
what important internal structures divides the atria from the ventricle
atria-ventricular valves (tricuspid and mitral valves)
what is the key feature that distinguishes the thoracic vertebrae from the cervical and lumbar
they have ribs attached to them
on an axial CT how can you tell if you are looking at the disks or the vertebral body
IV discs are less dense than bone so an compare to other bony structure to check - will appear darker than bone
bone is denser than cartilage so will be brighter white
how many pairs of ribs are there
12
why do we only see partial slices of the ribs when taken in axial cross section
ribs descend and then ascend again slightly and this makes it difficult to tell from a single slice
ribs are on different levels in body and don’t travel in one level, they slope down obliquely between different levels
what 3 elements of the vertebral column do typical ribs (2-9) articulate with posteriorly to form the costovertebral joints
vertebral body
transverse process of own level and vertebral body of level above
what are the 3 parts of the sternum
manubrium
mesosternum
xiphoid process
what is the relation that the 3 parts of the sternum have with the chest wall as a whole
it slopes posteriorly from xiphoid to manubrium
why wont you get a complete coronal view of the sternum
angled so wont get everything in a vertical slice
how do you tell where the mesosternum, manubrium and sternum are in a sagittal CT chest image
mesosternum = beneath aorta and carina of trachea at level of heart
manubrium = anterior to great vessels
xiphi = level of liver/lower ventricles of heart
the trans-thoracic plane sits in line with what joint
manubrium sternal joint
what characteristic feature does the trachea have when compared to most of the rest of the soft tissue nearby that might help you locate it on a CT/MRI slice
the trachea contains air
at what vertebral level is the trachea said to bifurcate
T4/5 transthoracic plane
at sternal angle
how many lobes does the right lung have and what are their names
superior
middle
inferior
how many lobes does the left lung have and what are their names
superior inferior
lingula
how many fissures does the right lung have and what are their names
oblique and horizontal
how many fissures does the left lung have and what are their names
oblique
where is the lingual lobe of the left lung located
at the inferior tip of the superior lobe near the medial border
ho far superiorly do the apex of the lungs extend normally
above rib 1 and behind collar bones into the lower neck region
which relationship of the upper lobes to the lower lobes of either lung might you expect to use most on an axial chest CT or MRI slice to differentiate them
upper lobes are more anterior to the lower lobes
lower lobes more posterior at some levels, AP association for axial slice - sup as lung fields are small and is tight, lower slice then lower lobe forms more
what are the 3 structures entering/exiting the hilum of the lung
pulmonary arteries, veins and bronchi
which of the 3 structures entering and exiting the lung at the hilum are most superiorly located
pulmonary arteries more superior
what features of the 3 hilum structures help you differentiate them in practice
Pulmonary trunk splits into pulmonary arteries in an upside down Y shape and is the most anterior vessel of the heart
Pulmonary veins are 4 in number and enter the left atrium which is the most posterior part of the heart
Pulmonary trunk and arteries cross beneath the arch of the aorta
what does the IVC enter
right atrium
what does the SVC enter
right atrium
what does the aorta exit
left ventricle
what does the pulmonary trunk exit
right ventricle
what does the pulmonary veins enter
left atrium
note the ascending aorta’s relative position to the pulmonary trunk in the axial slice - what might be confusing about this orientation considering where the vessels enter and exit from
aorta exits the left ventricle but is located on the right side of the pulmonary trunk which leaves the right ventricle
this is due to the twist of the heart so the artery you see on the right in the axial view is actually the aorta leaving the left ventricle
once the aorta has left the heart how would you describe its course
how can you use this to determine if you are looking at the ascending or descending portion on the axial slice
it arches slightly to the left from anterior to posterior
therefore anterior = ascending and posterior = descending
in what cross sectional view might you expect to see the entire length of the aorta from ascending to descending
sagittal
depending on how far it travels to the left from the heart
when scrolling from superior to inferior in an axial series what order do you expect to come across the following structures
imagine how they look in the axial view
pulmonary arteries/pulmonary trunk/arch of aorta/ascending aorta/pulmonary veins/IVC
1/ arch of aorta 2/ pulmonary arteries 3/ ascending aorta (and descending) 4/ pulmonary veins 5/ IVC
in the axial view what is the appearance of the aortic arch
appears as straight length of tube
in the axial view what is the appearance of the pulmonary trunk
appear as Y shape coming off pulmonary trunk
in the axial view what is the appearance of the ascending aorta
appear as circular cross sections
in the axial view what is the appearance of the pulmonary veins
1-2 each side entering the left atrium at back of the heart
in the axial view what is the appearance of the IVC
appears as a ellipsoid structure beneath right atrium at the bottom of the heart
the inferior aspect of the arch of the aorta and pulmonary trunk bifurcation lie on what plane at what vertebral level
trans-thoracic plane
T4/5 vertebral level
how might you expect the airways to appear at or around the trans-thoracic plane on an axial slice
variable but should start widening left-right as the trachea bifurcates or appear as 2 separate structures if slightly below the carina (left and right main bronchus)
where are the airways in relation to most of the great vessels
posterior to them
which is usually the most anterior vessel emerging from the heart
pulmonary trunk
