1. Human Anatomy I (1 03)

Class #1 – Prof. De Luca – Anatomy
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Class #1
Anatomy
Prof. De Luca – 1/03/2021
Lavinia Zozi – Matteo Di Marziantonio
1. Introduction to Anatomy
A brief introduction to the course is mandatory to let you understand what this class is about, and
the importance of knowing anatomy for medical students. If you think that anatomy is very old there
is a misunderstanding. We’ll see that this science, compared to math and physics, is relatively young
and a lot of passionate people who studied it weren’t actually doctors: this beautiful painting by
Michelangelo, the Last Judgement, is an example. I chose this quadrant of the painting because we
can appreciate the perfect details of the surface anatomy and all the muscles underneath shaped
with the shadow ability of Michelangelo to represent them, and also because it is a sort of metaphor
for your future studies: you will need to know the human body from the surface to its bones, it will
not be easy but if you take it with the right
motivation and spirit, not like a boring thing,
then you’ll see that it will make a difference. The
other metaphor is about the examination: you
should recognize that this is a fresco, that it’ the
Last Judgement, know the author (Michelangelo)
and that it’s in the Sistine Chapel. In this
quadrant of the wall Michelangelo portraits the
flayed San Bartholomew holding his flayed skin
(the skin is there because in the Last Judgement
he was in paradise, while on earth they skinned
him). Also, some authors say that the face
portrayed is the face of Michelangelo himself.
1.2 Anatomical terminology
Terminology is important in anatomy because we need to understand each other and move to all
the sections of a person’s body without making mistakes, and to do that we need to speak clearly
with an international standardized anatomical terminology: FICAT (Federal International
Committee on Anatomical Terminology) created in 1989. You weren’t born at that time, but you
can understand that it’s relatively recent.
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1.3 Regional and systemic approach
The important thing to know is that typically to make a description of anatomy we need to divide
in superficial gross anatomy (what we see without magnification) and microscopic anatomy. The
term anatomy derives from the Greek “dissection”, so the superficial parts are what we see before
dissection.
To understand a patient’s disease, it is important to check the surface, not just the skin: many
cavities are accessible from the surface, like the oral cavity, nasal cavities, so you can ask the
patient to open his mouth and vocalize, and also observe the muscles movement. The word
muscle derives from Latin, because the shape formed by muscle movement underneath the skin
looked like a mouse moving beneath something (so the word muscle and mice have same root).
We will use the regional approach and we will try to understand why we’ll use it. We study each
region of the body separately with all the systems that can be traced inside that region; when
studying a region, the systems will be added as layers but considered at the same time. If we study
the head, we will go from bones, then add muscles, nerves and vessels, that are part of different
systems, to perceive how the systems are integrated and that’s the pro of the regional approach:
the body can be defined as unity. Many universities use the systemic approach, where each
system is studied separately and it could be useful to concentrate your attention on the details of
the systems, however there are pros and cons in this approach. We decide to use regional because
it is more intuitive and easier for the students to have the image of the atlas in front and
understand how the systems combine all together without losing information.
1.4 Anatomical planes
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In the standard reference position, the person is standing upright, with feet together, hands on
the side, the face looks forward with a neutral facial expression to let you see the symmetry
without muscular contraction. The mouth is closed, and the orientation of the head lets the rim of
the bone under the eyes be on the horizontal plane, in line with the opening of the ear. About the
hands position, palms face forward with fingers pointing straight down, and the thumb turned
about 90 degrees to the pads of the fingers. The feet are united together and toes are pointing
forward.
The female in the picture is representing the anatomical planes, that’s how we will describe
anatomy: we cut and dissect. The planes are useful because they let us see which layers are upon
each other. You can describe the coronal plane, depicted in the picture in green, the sagittal plane
in blue, the transverse plane cutting horizontally (also called axial plane). These planes will come
with many sections so you will recognize superior, anterior, posterior, medial or lateral and
inferior structures. It’s more intuitive speaking this way.
There are also synonyms, for example the word anterior can be said ventral, posterior can be said
also dorsal. The terms ventral and dorsal are used for all the human body, but specially referring
to the dorsal and ventral part of the trunk.
The proximal and distal terms mean that there is a reference closer or farther from the origin of
the structure, specially used when describing limbs (distal and proximal parts of the upper limb).
You will tend to call all the upper limbs “arms” but you have to know that common tongue is not
the anatomical way of speaking.
Cranial is used to refer to what’s going towards the head, while caudal means towards the tail (lost
with evolution, but we still have a remnant of the tail).
Rostral can be used to refer to something that points towards the head, particularly used for
nervous central system and brain.
The last terms are superficial and deep: we’ll go from the surface to the deepest parts of the body,
so you’ll describe the structures in layers, it’s important because the superficial region of the body
is external to a sort of sheet that covers almost all the body, with exception of the head: it is called
the fascia. What lies underneath the fascia are deep structures, while what’s in the more
superficial region is in the so-called superficial fascia, which is part of the cutaneous organs (in
females the mammary glands are an example). It is also useful for practice, because superficial
wounds can be described as external to the fascia, otherwise they are called deep wounds.
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This is the image that you have to keep in
mind when you describe a patient: a
patient doesn’t tell you he has a T12 pain
or that he has pain in the 6th rib region, he
will only point it, so studying human
anatomy and understanding the body
from the surface to the deepest regions
you will have in mind the levels, the
structures underneath them, and all the
planes that can cut the body.
As said before, anatomy is not an old. But in the past, the Egyptians described in scientific way
many structures as an accounting of a description of organs without any information about their
physiology or the implications in pathology. Then Hippocrates, with a brief contribution of
Galenus, mostly described pathology in humans and structures in animals. Andreas Vesalius, an
important Belgian author, described the errors of Galenus. They made mistakes because at that
time they were not allowed to practice with cadavers for many anthropological reasons (and now
we do); we are in 1543 when anatomy was officially born.
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These are images from Mascagni, a great anatomist, who painted this beautiful representation. He
did this drawing with a ratio 1:1. Here we are in the 18/19 century, flourishing moment for
anatomy studies.
This section of the brain was painted by one of the most important neuroscientist. He drew this
image just as many neuroscientists did, just because he liked to understand the complexity and
the shapes of the grey and white matter, to advance his knowledge without a specific purpose.
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Galenus said that all his work was pure speculation because he didn’t understand at the moment
that the structures where directly related to pathophysiology, saying that it was love for
knowledge. Very often you don’t know why you are studying something, and then it becomes a
great discovery. Most of the time you will be astonished how things can change without a precise
reason.
This image will be useful to understand this concept: Wilhelm Rontgen was experimenting with a
scientific tool, the cathode tube. Rays of light were passing through a cathode tube: he tried to
impress these rays and, not knowing what they were, he called them x-rays (they are also called
Rontgen rays). In the picture we can see a hand, and it’s his wife’s hand, which first image ever of
the body obtained using x-rays. He studied the electric field in the vacuum tube, and in the end he
obtained this important image. From that moment many features of radiography were developed
using x-rays both with direct impression and subtraction, with or without substances that allow to
see structures that are transparent. X-rays can be dangerous and modify DNA, and that’s why we
should use them with moderation. X-rays can pass through the structures and some structures will
block the rays, and some can attenuate them (the bones, being calcified, are the most attenuating
part of the body). If the rays encounter fat or water, these structures will be less attenuated.
These differences can be modified injecting some substances (contrast agents). In the picture on
the left we see an intestine of a patient: the patient drinks a contrast, thanks to the contrast you
can see what otherwise you wouldn’t see (using barium sulfate, a direct agent). In the arteries the
contrast is darker, it is a subtraction contrast, you can see in black what should be white: it is used
for angiogram with contrast agents that are usually based on iodine. Iodine can attenuate the xrays without being toxic and can be naturally excreted through the urinary system, so the contrast
is injected intra-arterially and then excreted. In subtraction angiography you demonstrate the
passage of the contrast agent adding the negative pre-contrast image, and then subtracting it to
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the positive contrast image. I cannot just use the positive contrast image because I would see also
all the parts around, while if you do the subtraction you see what’s remaining without all the
bone, fat tissues and the other organs, because they are just abolished instantaneously with
software analysis.
1.5 THE CT SCAN
So, we didn't answer the question about why we should know the section and draw the anatomy
if we cannot see the whole thing in our leaving patient? So, these are x-rays altogether, but with a
technical different positioning of the detectors you can form a sort of greed on the other side of
the X Ray and you will just have the whole body reconstruction and that's why the CT scan was
called CAT scan because it was practically impossible to acquire images just in the axial plane. Now
with this multiple detectors, X Ray is multiaxial so all the planes that we saw in the 1st image with
two bodies in anatomical position can be acquired and visualized by the doctor (I think it’s not
useful for you to have the technical understanding of the CT, but it could be useful to understand
that an X Ray is causing you tumor).
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1.6 THE MRI
But can we avoid these dangerous X Rays,
these high energy X Rays, and use another
system? Yes, of course, I'll just avoid
reconstructing the structure: then the MRI was
discovered, but it was not built in the first
place for medical reasons. We are just using a
gradual frequency that's very low energy
compared to X Rays and magnetic fields, so
what's the point of that? You can interfere with
the magnetic field graduating it along 1 axis or
multiple axis and give a radio frequency to
disturb the orientation of the align and register the parameters. So, why are we not using just the
MRI and avoiding the dangerous CT scans? For many reasons actually. The first is that CT scans are
not dangerous when used properly and MRI offers you multi-planner and multiparametric images
that are different from CT scan images. As you can see in this image, you can clearly see the brain
and its details with a 7-Tesla MRI, things that you cannot see with the CT scan, for intrinsic
limitations due to how they work. But of course you can't use that imaging with all patients, for
example because a high magnetic field could not be employed with someone that has metal inside
him that is not a metal that can be used in MRI, and even materials that have been developed to
be friendly with the MRI can, with the access to high magnetic field and radio frequency, warm up
and so you have a limited time and you have to stay there quite long time just to obtain section
and it depends of how many parameters of the MRI you want to acquire and how many sections,
so for the 3D reconstruction the times are very long.
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As you can see in this image of a 7-Tesla machine, it’s a very close ambient for people that are not
very comfortable in small spaces and they will not be very happy to perform and do these
examinations, and you need to consider that of course. The MRI has also contrast agents and you
need to understand also the comorbidities of your patients and, for example, that renal failure
needs to be considered if you want to do contrast images or radiologists will be very angry with
you. So, what's the point of all that? It’s that you know when and why perform an image, you can
just read what the radiologist said (that's the doctors’ everyday job), but it's also useful to know
what you want to see and to see it by yourself.
Here you can observe the beauty and
that's the only reason I rejected this
image. Anatomic details that can be
scanned through a human person that
were actually seen just in pieces, with
the section performed by expert people,
quite useless but of course they were
useful for research: we didn't understand
anything about Parkinson's disease and
Alzheimer's disease until someone tried
hard to visualize what are the structures
that were suffering in human brain and
which proteins were inside the tissues.
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So that's the recording and you can
see at this point your patient and look forward to what to study. All the structures can be
observed, recognized and pathological processes that can affect every one of them.
But can we just see the structure or the structure means something else? The structure means
function and so you can register and
combine the data about the
structure and what the cells are
doing. For example neurons
employing electric signals and the
electric field make always a
magnetic field that's perpendicular
to it, and we can register both if you
do an EEG on your patient and
electroencephalography you can
reduce the electric potential
difference between two points on
the scalp or between one point on
the scalp and a common reference
point and you can see if there are
neurons that are firing improperly
like in epilepsy .With the
electroencephalography, you can
deploy with the map if there is an
overlapping of the magnetic field. I'm just doing that not because this is actually useful for your
examination but to let you understand the frontiers and perspectives of your potential future job
with an eye on the actual problems that you have and the problems that maybe you’ll have in the
future. That's a sort of recap of what I was, that's the whole brain and you can just check
structures. It just analyzes how much glucose is taken by the cells, and that's very useful in
degenerative diseases, for example for the diagnostic of Alzheimer's disease: you see the red that
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means that there's a high glucose metabolism, the yellow and blue mean there is a low energetic
value.
Back to what we do where with planes. Radiographs allow us to see the structure underneath the
skin with the ability of X Rays to penetrate it and be partially attenuated by the structure: you can
recognize the rib cage, the heart and clavicles and you have to you could think that that's it, but of
course the same image can be acquired with a CT scan and a planner CD image allow us to see just
one section, so you see that the structures are not one upon the other, so you can't see all the
structural together and this the advantage that can lead you to visualize a single structure but also
will let you lose the sense of in “interiority” of the system, that's not actually a real problem
because multi-planner images can be assembled.
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Here with the contrast for the vessels you can visualize the Arctic arch and all the main arteries
that are in this system.
1.7 ULTRASOUNDS
You can see, according to the frequency
that you can use applied to the scheme
of ultrasounds, structures that are
superficial or quite deep in a patient's
live body and you can see here that you
can study the section of femoral artery
and also visualize the femoral nerve.
This is an instrument that many doctors
use every day, and the beauty of this
instrument is that
you can perform the examination while
you are doing the clinical part of the
evaluation, and you can move directly on the structure observing the planes just moving around.
You can apply also another physic instrument that's the Doppler effect: it's in practice what you
experience when a sound is moving towards you or moving away. Then when it will pass through
it will decrease its wavelength and so you can apply it to the motion fluids with the ultrasound,
that's of course sound that cannot be heard by our system but it is of the same physical nature.
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Ultrasounds are also used when performing a fetal echography, so you are seeing a human being
inside another human being, or you can also perform an endo-echography showing, for example,
the vaginal canal of pregnant women.
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