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REGIONAL COOPERATIVE AGREEMENT
INTERNATIONAL ATOMIC ENERGY AGENCY
Distance Assisted Training Programme
for
Nuclear Medicine Technologists
Edited by: Heather E. Patterson, Brian F. Hutton
An introduction to
Cross Sectional Anatomy
PART 1:
PART 2:
Authors:
Elisabeth Kilburn-Watt
Paul Roach, Denis Gradinscak
Scott Evans, Robin Cassumbhoy
Module
Unit
The material within this document should be regarded as the property of the International Atomic
Energy Agency and should be reproduced or used only in accordance with the attached statement of
ownership.
(version 4)
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Introduction to Sectional Anatomy
CONTENTS
page
Flowchart
c
Outline
1
PART 1
What is Sectional Anatomy
1
The language of sectional anatomy
Planes
Sections
2
4
5
Sectional anatomy of the chest
8
Sectional anatomy of the abdomen
13
Sectional anatomy of the pelvis
18
Sectional anatomy of the brain
Transverse
Coronal
20
22
25
PART 2
An Exercise on familiarity with Cross Sectional Anatomy on the internet
DAT website on‐line familiarity with CT Cross Sectional Anatomy and integration with SPECT and PET. c
29
Introduction to Sectional Anatomy What is Sectional Anatomy The language of sectional anatomy Planes Sections Sectional anatomy of the chest Exercise
Sectional anatomy of the abdomen and pelvis Exercise
Sectional anatomy of the brain Transverse Coronal Exercise
Exercise
www various
interactive websites
PART 2 OL – DAT web activity d
Introduction to
Cross Sectional Anatomy
Technical Writer:
Production Editor:
Elisabeth Kilburn-Watt
Heather Patterson
Outline:
Traditionally, the images we have taken in Nuclear Medicine have been 'planar'
images. By this, we mean that when we collect and display images of the
distribution of a radiopharmaceutical in the body (or organ), it is as though the
distribution was in a single plane or on a flat surface. There is no 'depth' to the
images. An anterior view obtained with a stationary camera is a 'flat' image of
the distribution of activity. It gives us little idea of the location of a hot or cold
spot in an organ, such as the liver, in terms of whether it lies anteriorly or
posteriorly in the organ. We have been able to obtain further information about
the anatomical position of a lesion by taking lateral or oblique views. By looking
at an organ in a number of 'flat' images taken from different view points, we are
able to get an idea of the location of a structure that is deep within the body.
With the development of SPECT camera systems, we have the ability to display
radiopharmaceutical distribution to show the structures of the body in cross
sectional planes. That is, in planes (or flat surfaces) that could be obtained by
cutting/slicing the body and viewing an internal surface. We are looking at our
organs from a totally different viewpoint. This means we have to be able to
recognise our anatomical structures from this different viewpoint. We need to
have some knowledge of Sectional Anatomy.
More recently the introduction of SPECT/CT and PET/CT enables further
enhancement and localisation of organs, vessels and other structures through
image fusion. i.e. the ability to view exact positions of areas with
radiopharmaceutical uptake such as functioning organs and active tumours
within surrounding structures as imaged with Computerised Tomography.
At the conclusion of Part 1 there are directions to several websites on the internet
which you are encouraged to explore and further enhance your knowledge and
ability to recognise anatomical locations in transverse, sagittal and coronal
planes.
In Part 2 of this Unit you will be directed to log_on to the DAT website and
follow the links to ………… (name). Here you can step through the slices of
transverse, coronal and sagittal views in CT, PET and fused images with labelled
areas of interest to help orientate their locations. There are self assessment tests
to assist with your understanding during your study of this Unit followed by
‘on-line’ multiple choice questions which will record your results as part of your
final assessment.
1
Objectives:
•
•
•
•
On completion of this unit you will be able to
look at anatomy in a different way
recognise the structures you are already familiar with when they are displayed
in different sectional planes.
demonstrate interactive control as you move through transverse, coronal and
sagittal slices on-line.
identify locations of functioning organs, vessels and tumour sites within the
body structures
As well, this module is meant only as an introduction to sectional anatomy. We
will not be going into the depth of detail that would be found in a full sectional
anatomy course. This module should be a good introduction to such a course if
you want to take one in the future.
Time Check:
Allow 8 hours to study and complete PART 1 on Cross Sectional Anatomy and
a further 6 hours to complete PART 2 on-line.
2
Introduction:
What is Sectional Anatomy?
Sectional Anatomy is concerned with the position and anatomical relationships
of structures of the body in various sectional planes. When we first learn
anatomy we tend to learn it as though we are looking at the body from the front
or the back - much like what we tend to see on an anterior or a posterior planar
image. We learn some superior and inferior relationships - we learn where the
kidneys are relative to the ribs and the pelvis - but we don't tend to think where
the colon is relative to the left kidney or where the stomach lies relative to the
spleen and left kidney. Which one is more anterior? Or lateral? Or superior?
However if we are going to be looking at sectional images through the abdomen,
we need to know some of these relationships so that we can correctly identify
structures on different slices.
Sectional anatomy is best learned by looking at Computed Tomography (CT) or
Magnetic Resonance Imaging (MRI) images or sectional anatomical specimens
because they show so much detail and give so much information about the
relationships between organs. The anatomical detail seen on a CT scan is much
greater than we can see on SPECT images. However, what we can learn from
this material can give us the skills to interpret anatomy on our own images.
What this Sectional Anatomy Unit is Not?
It is not intended that this unit will teach you anatomy. It is assumed that you
have knowledge of traditional anatomy.
Note !
Pre-requisite
If you find that there are anatomical structures referred to that you are not
familiar with, you may need to revise the anatomy of that organ or organ system
before continuing with this work/refer to a textbook of anatomy for this
information.
The Language of Sectional Anatomy
Firstly, we need to look at the terminology/language that is used in sectional
anatomy. Because sectional anatomy looks at the relationships between organs,
the language/terminology used is about the position of structures relative to one
another.
You will be familiar with most of these terms already. Please refer to Figure 1 to
remind yourself about these terms and what they mean.
3
Superior
Medial
Lateral
Proximal end
of forelimb
Distal end of forelimb
Proximal end of thigh
Distal end of thigh
Proximal
end of leg
Lateral region of leg
Medial region of leg
Distal
end of feet
Inferior
Posterior
view
Anterior
view
Figure 1.
The body in the anatomical position and some directional terms.
The body is erect, eyes forward, arms at the sides and palms and toes directed
forward.
Adapted from: Human Anatomy and Physiology - Solomon & Davis.
Publisher New York McGraw-Hill, ©1978. • ISBN: 007059645X
The most commonly used terms are as follows:
Superior (cranial)
towards the head or the upper
part of a structure
Inferior (caudal)
away from the head or towards
the lower part of a structure
Anterior (ventral)
nearer to or at the front of the
body
Posterior (dorsal)
nearer to or at the back of the
body
Lateral
further from the midline of the
body or a structure
Medial
Adjacent
Proximal
Distal
•
•
nearer to the midline of the
body or structure
next to or very close to
nearer to the point of origin or
attachment to the trunk
further from the point of origin
or attachment to the trunk
eg - the heart is superior
to the liver
eg - the stomach is
inferior to the lungs
eg - the sternum is
anterior to the heart
eg - the oesophagus is
posterior to the trachea
eg - the ascending colon
is lateral to the urinary
bladder
eg - the ulna is medial to
the radius
eg - the superior vena
cava is adjacent to the
aorta
eg - the humerus is
proximal to the radius
eg - the carpal bones are
distal to the radius
Combinations of these words are often used such as:
postero-lateral - nearer to the back and further from the midline
For example: - the spleen is postero-lateral to the stomach
antero-medial - nearer to the front and closer to the midline
For example: - the right ventricle is antero-medial to the left ventricle
4
Planes and Sections
a)
Planes
The human body and its anatomy can be discussed with respect to a number of
planes. These are imaginary flat surfaces that pass through the body.
Please refer to Figure 2
Cranial
(superior)
Frontal (coronal) plane
Mid-sagittal plane
Transverse plane
Posterior (dorsal)
Anterior (ventral)
Inferior
Adapted from: Human Anatomy and Physiology - Solomon & Davis.
Publisher New York McGraw-Hill, ©1978. • ISBN: 007059645X
Figure 2.
Planes of section. The body or its parts may be cut in sagittal,
transverse or coronal sections. The commonly used planes (imaginary surfaces)
are shown in the diagram - all the terminology used refers to the body in the
upright anatomical position:
A sagittal plane is a vertical plane that divides the body (and organs) into right
and left sides. A mid-sagittal plane (also called a median plane) is the vertical
plane that passes through the midline of the body and divides it into equal right
and left sides. A para-sagittal plane does not pass through the midline and so
divides the body into right and left sides that are not equal.
A frontal plane - also called a coronal plane - is an imaginary flat surface at
right angles to a mid-sagittal or para-sagittal plane and divides the body into
anterior and posterior portions.
A horizontal or transverse plane is one that is horizontal to the ground (and at
right angles to both sagittal and frontal planes) and divides the body and organs
into superior and inferior portions.
5
b)
Sections
When we study sectional anatomy, we are looking at the organs in sections - or
flat surfaces - made by cutting through the three dimensional body along one of
these planes.
When we look at SPECT, CT and MRI images, a computer has been used to
reconstruct the data and display it as images as if the body has been cut in these
sections.
Sagittal sections
A sagittal section is made by cutting along a sagittal plane. The cut surface can
then be viewed. It would be possible to make a number of sagittal sections of
the body, all parallel to one another (one of which would be the mid-sagittal
section).
•
•
•
If you looked at the sections of the body, in order from right to left, you would
be able to identify the various organs and tissues in each section and how they
relate to one another.
Sagittal sections give information about the anterior/posterior and
superior/inferior relationship of structures.
For example:
Starting from the right side, as you look at sagittal sections at the level of the
upper abdomen, the liver is the most obvious structure you see. You obtain
information about other structures relative to the liver – e.g. the structures
which are superior (e.g. diaphragm) and inferior (e.g. right kidney) as well as
structures which are anterior and posterior.
As you view the sections going towards the left, you would expect to see the
liver get smaller and finally disappear as the stomach and then the spleen
became visible.
Coronal sections
Similarly, coronal sections are made by cutting the body in parallel coronal
planes.
•
•
•
These coronal sections give information about superior/inferior relationships of
structures and medial/lateral relationships.
To get information about anterior/posterior relationships, you have to view the
sequence of slices eg starting from the anterior aspect and moving through to
the posterior.
Coronal sections of the brain for example are useful for looking at the
relationship of the basal ganglia (which are more lateral) to the third ventricle
(which is a medial structure).
Transverse sections
The most commonly used sections are transverse sections – they are also called
axial sections or cross sections. These are obtained by cutting the body in
parallel transverse planes and are viewed as though we were looking up from
the patient's feet.
6
•
•
Cross sectional slices give information about anterior/posterior relationships
and medial/lateral relationships.
To get information about superior/inferior structures, you again have to look at
a series of slices.
For example:
Looking at cross sectional slices of the abdomen; moving down from the
diaphragm towards the pelvis, you will see structures such as the liver, stomach
and spleen, then these will disappear as the kidneys and then pelvic organs
appear.
Remember
Being able to identify anatomy from these different viewpoints takes time and
practice. You need to translate your knowledge of anatomy in the “normal”
plane (i.e. in text books of anatomy) into the axial plane. You need to understand
how the shape and orientation of anatomy is viewed in other planes.
For example:
Look at the images below.
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Figure 3.
Eight cross sectional/slices of a walking stick.
7
Figure 4a. An apple has been scanned.
Figure 4b.
Note: skin, stem seeds and air in core.
[Flaws in the apple are soft spots, not bites]
The above images demonstrate
•
Figure 3.
How a walking stick would appear if we were to scan it and then view it in
transverse sections. What we have to learn to do is to look at the sections and
reconstruct in our minds the three dimensional structure of the curved handle of
the stick.
Note: This structure is very similar to the aorta – the ascending portion of the aorta as it
leaves the left ventricle and then the descending aorta as it passes down through
the chest. Depending on the level at which we make a transverse section
through the chest, the aorta may appear on our section in a number of ways.
•
Figures 4a and 4b.
This is a scan of a familiar object – an apple – but getting used to thinking of an
apple in this way takes some practice.
The main purpose of this module is to give you practice at looking at different
sections and identifying the structures that you can see. When you have
identified the various structures (and using the other diagrams to help you
identify the level you are at), follow the structures as you look at a number of
slices. Notice how the structures change shape, how they disappear and new
structures appear. Notice the relationship of the various structures to another.
Diagrams and either CT or MRI scans have been used to help you identify the
structures. Use the labelled diagrams to help you identify the structures on the
scans.
8
In your workbook there is another set of images. Once you feel confident about
identifying the various structures, try labelling these diagrams. There are also
some questions about the relationship of various structures and the section that
would be used to best display different structures.
Sectional Anatomy of the Chest
To start looking at the chest in transverse sections, we first need to have a good
idea of the structures in the chest and their relation to one another. Look at the
following diagrams showing an anterior and a lateral view of the heart.
Inferior pharyngeal
constrictor muscle
Thyroid cartilage
Cricoid cartilage
Cricopharyngeus muscle
1
Pulmonary valve 1
Aorta
Sternum
2
2
A
3
Trachea
Esophagus
P
Heart in
pericardium
3
Aortic
valve
4
4
Diaphragm
5
T Mitral valve
5
M
6
6
7
Tricuspid valve
Anterior view of the heart
7
Left lateral view of the heart
Figure 5.
Looking at these views together we can get information about
anterior/posterior, inferior/superior and medial/lateral relationships within
the heart which will help us with identifying structures on transverse sections.
For example:
THINK!
•
•
•
•
•
•
•
How does the heart lie in the thorax?
Where is it located?
Which chamber of the heart is most anterior?
Which chamber is most posterior?
Are the atria superior and the ventricles inferior as most diagrams show?
Which is superior, the aorta or the pulmonary artery?
What is the position of the superior vena cava relative to the aorta?
If you have a understanding about these relationships it makes looking at
transverse sections easier.
9
The following diagram shows the approximate levels at which the transverse
sections of the chest were made. Use it to help you identify structures in the
next three sections.
Diagram showing levels of transverse sections of the chest
T1
T2
section 1
section 2
T9
section 3
T 10
T 11
T 12
Figure 6.
Diagram showing levels of transverse sections of the chest
10
Right Lung
Mediastinal
fat
Sternum
Left Lung
Superior vena cava
Ascending aorta
R. pulmonary a.
R. superior pulmonary v.
Pulmonary trunk
L. superior pulmonary v.
R. bronchus intermedius
L. upper lobe bronchus
Esophagus
Descending branch of
l. pulmonary a.
Azygos v.
L. main bronchus
Descending aorta
Figure 7a. Section 1: Transverse section of chest at the level of T6
Fig 7b. CT scan of chest at the level of T6 Fig 7c. SPECT 67Ga study at level T6
Figure 7a, b & c.
•
•
•
•
•
•
The CT transverse section shown in figure 7b is taken approximately at the
level of the 6th thoracic vertebra.
The section passes through the pulmonary artery at the point where it gives rise
to the right pulmonary artery and below the origin of the left pulmonary artery
(which is why it appears as a separate circle – think of the walking stick).
The section is also below the arch of the aorta – so the ascending and
descending arteries appear separately – note their relative positions.
Comparing the diagram with the CT scan makes it easy to identify the
structures that are filled with air – the lungs and the bronchi.
The bony structures are also easy to identify on the CT scan due to the high
density of bone – identify the sternum, vertebra, ribs (some of these are cut
because they are not horizontal structures).
Identify the superior vena cava and the oesophagus.
Where is the trachea?
*************************************
11
Fleck of calcium in
ascending aorta
R. ventricle
L. ventricle
R. atrium
Diaphragm and
top of liver
L. atrium
R. inferior
pulmonary v.
L. inferior
pulmonary v.
Descending aorta
Esophagus
Azygos v.
Figure 8a.
Section 2: Transverse section of chest at the level of T8
Fig 8b. CT scan of chest at the level of T8 Fig 8c. SPECT 67Ga study of level T8
•
•
•
•
•
Figures 8a, b & c
The transverse section shown in figure 8b is taken approximately at the level of
T8.
Note the relationship of the right and left ventricles – remember the orientation
is as though the patient is lying supine and we are looking up from his feet
towards his head.
Note the positions of the right and left atria.
Note that we are now below the level of the pulmonary arteries (but we can see
the pulmonary veins) and we no longer see the superior vena cava.
We can still see the ascending aorta.
The dome of the right lobe of the liver is now visible.
******************************************
12
R. lung in anterior
costodiaphragmatic
recess
R. ventricle
Interventricular
septum
R. atrium
L. ventricle
Pericardium
Liver
L. atrium
Esophagus
Descending aorta
Azygos v.
Figure 9a.
Hemiazygos v.
Section 3: Transverse section of chest at the level of T9 / T10
Fig 9a. CT scan of chest at the level
of T9/T10
•
•
•
•
•
Fig 9b. SPECT 67Ga study at the level
of T9/T10
Figures 9a, b & c
The next section is taken a little below at approximately T9 / T10.
Note the relative positions of the ventricles and the interventricular septum.
Note the pericardium.
The ascending aorta is no longer visible.
Note how far posterior the descending aorta lies.
The right lobe of the liver is more obvious.
Go to your Workbook Sectional Anatomy and complete question 1
13
Sectional Anatomy of the Abdomen and Pelvis
To be able to appreciate transverse sections of the abdomen, we again need to
look at an anterior view (coronal section) to remind ourselves of the relationship
of the various organs.
Look at figure 10 to remind you of what you would expect to find at different
levels. Because it is a diagram with some organs removed it also gives you some
idea of the anterior/posterior relationships. Use it to get some idea of the
relative position of the structures before moving on to the transverse sections.
Where is the pancreas relative to the spleen? Where is the abdominal aorta
relative to the superior vena cava? What is the relationship of the gall bladder
relative to the pelvis of the right kidney? Which is superior, the portal vein, the
hepatic veins or the hepatic artery? Ask yourself these types of questions – it
will help you develop a three dimensional view of the abdomen.
Inferior vena cava
Aorta
Hepatic veins
Left gastric a.
Splenic a.
Liver
Spleen
Inferior
vena cava
Tail of
pancreas
Gall bladder
Celiac trunk
Common
bile duct
Common hepatic a.
Duodenum
Major duodenal
papilla (ampulla of Vater)
Superior mesenteric a.
Superior mesenteric v.
Pancreatic duct
Inferior vena cava
Head of pancreas
Aorta
Figure 10.
Diagram of the abdomen
14
Diagram showing levels of transverse sections of the abdomen
section 1
T-12
section 2
L-1
L-2
section 3
L-3
L-4
L-5
Figure 11.
This diagram shows you the approximate levels at which the
transverse sections of the abdomen were taken. It should help you to identify
the various structures you see.
15
Muscular insertions of
diaphragm
Groove for ligamentum teres
Stomach
Gastroesophageal
junction
middle and r. hepatic vs
Descending aorta
Inferior vena cava
Spleen
R. lobe of liver
L. Lung in posterior
costodiaphragmatic recess
Azygos and hemiazygos
R. lung in posterior
costodiaphragmatic
Figure 12a.
Section 1: Transverse section of abdomen at the level of T11
Fig 12b. CT scan of abdomen
at the level of T11
•
•
•
•
Fig 12c. SPECT 99mTc-MIBI study
at the level of T11
Figures 12a, b & c. This transverse section is taken at approximately the level of
the 11th thoracic vertebra.
The most obvious structure is the liver – note the right and left lobes – note the
relative position of the spleen and the left lobe of the liver.
Identify the inferior vena cava and the hepatic veins draining into it.
Note that the posterior inferior portions of the lung are still visible.
Identify the stomach and the inferior portion of the oesophagus.
Note again the position of the aorta.
***********************************************
16
Lateral segment,
l. lobe of liver
Medial segment,
l. lobe of liver
Splenic flexure of colon
Interlobar fissure
Stomach
Common hepatic a.
Celiac trunk
Portal v.
Tail of pancreas
Inferior vena cava
L. adrenal
R. adrenal
Aorta
Calcium in aorta
L. kidney
Osteophyte
Figure 13a.
L. crus of diaphragm
Section 2: Transverse section of abdomen at the level of L1
Figure 13b. CT scan of abdomen
at the level of L1
Figure 13c. SPECT 99mTc-MIBI study
at the level of L1
Figures 13a & b
This transverse section is taken a little below figure 12, at
about the level of the 1st lumbar vertebra.
•
•
•
•
•
•
The liver is still the most prominent structure on the right side – identify the
portal vein and the hepatic artery.
Note that the stomach is now seen as a smaller structure - this would be the
inferior portion of the body of the stomach.
Identify the splenic flexure of the colon and the tail of the pancreas – why is only
the tail seen here?
Note that the left kidney is now seen – why not the right kidney?
Note that both adrenal glands are seen – they appear like “flying birds” on the
CT scan.
Identify the inferior vena cava and note its position relative to the aorta.
****************************************************
17
Pyloric antrum
of stomach
Gallbladder
Distal transvers
colon
R. lobe of liver
Body of pancreas
Duodenum
Superior mesenteric v.
Usual site of
common bile duct
in head of pancreas
Superior mesenteric a.
Small bowel loops
Inferior vena cava
Descending colon
Aorta
L. renal a.
L. kidney
R. kidney
Figure 14a.
Section 3: Transverse section of abdomen at the level of L2
Figure 14b. CT scan of abdomen
at the level of L2
Figures 14a, b &c.
•
•
•
•
•
•
•
•
Figure 14c. SPECT 99mTc-MIBI study
at the level of L2
This section is a little lower again – about the level of L2.
The liver appears smaller here – only the right lobe of the liver would extend
down to this level.
Identify the gall bladder – note how anterior it is in this patient.
Identify the stomach – it seems larger again – this is because this slice/section is
taken through the pylorus of the stomach which is like a tube.
Note how far to the right side the pylorus of the stomach extends – it is then
continuous with the beginning of the duodenum which then disappears as it
continues inferiorly.
Identify the head and body of the pancreas – the tail was visible in the slice
above because it is superior to the body.
Note the location of portions of small and large bowel.
Identify the left kidney and the left renal artery arising from the aorta – the
upper pole of the right kidney is now visible.
Note the relative positions of the inferior vena cava and the aorta.
18
The next two sections are taken through the pelvis.
The main interest we have in the pelvis is the bony structures which are shown
very well on the CT scans. However it is interesting to note the position of the
ureters and the iliac vessels as well as the relationship of the urinary bladder
and the prostate gland.
Small bowel
Fat around tendon
in psoas m.
Anterior superior
illiac spine
Lumbosacral
trunk
Iliacus m.
Iliac wing
L. ureter
L. common iliac a.
Gluteus minimus m.
Gluteus medius m.
L. internal iliac v.
L. external iliac v.
Sacroiliac joint
Gluteus maximus m.
Neural foramina
in sacrum
Figure 15a.
Transverse section of the pelvis at the level of S1
Figure 15b. CT scan of abdomen
at the level of S1
•
•
•
•
•
•
Figure 15c. SPECT 99mTc-MIBI study
at the level of S1
Figures 15a, b & c. This is a transverse section of the pelvis at the level of 1st
sacral vertebra.
Identify the sacrum and the sacroiliac joints.
Note the positions of the iliac arteries and their position relative to the iliac
veins.
Identify the ureters.
Identify loops of small bowel
Note the large muscle masses associated with the pelvis.
Unlike the sections in the abdomen, this slice appears symmetrical, there are no
obvious right or left sided structures.
Important
to
Remember
It is important to remember our orientation - we are looking from the patient’s
feet toward his head - so his right is on our left (as for an anterior view).
19
Femoral a. and v.
Symphysis pubis
Sartorius m.
Iliopsoas
Rectus femoris m.
Pectineus m.
Tensor fasciae latae m.
Oburator canal
Prostate and
bladder neck
Acetabulum
Head of femur
Ischium
Gluteus maximus m.
Transverse perineal m.
Rectum
Coccyx
Levator ani m.
Figure 16a.
Transverse section of the pelvis at the level of the coccyx
Fig 16b. CT scan of the pelvis
at the level of coccyx
Fig 16c.
SPECT 99mTc-MIBI study
at the level of coccyx
Figures 16a, b & c. This transverse section is at the level of the coccyx.
•
•
•
•
•
Identify the pubic bones and the symphysis pubis.
Identify the head of the femur and the acetabulum.
Note the position of the prostrate gland and the neck of the urinary bladder (the
body of the bladder was on slices between figure 15 and 16).
Note the position of the rectum relative to the bladder neck.
Again note the large muscle masses in the pelvic area.
Go to your Workbook Sectional Anatomy and complete question 2
20
Sectional Anatomy of the Brain
The brain is a very complex anatomical structure. The best view to start with to
identify the various structures is a mid-sagittal section.
Mid-sagittal Section of the Brain
POSTERIOR
Choroid plexus of third ventricle
Superior cerebral
vein
Parietal lobe
Intermediate mass
of thalamus
Corpus callosum
Arachnoid villus
Subarachnoid space
surrounding brain
Superior sagittal sinus
Cerebrum
Frontal lobe
Lateral ventricle
Interventricular foramen
Occipital lobe
Pineal gland
Great cerebral vein
Third ventricle
Straight sinus
midbrain*
Pituitary gland
Pons
Cererbellum
Cerebral aqueduct
Choroid plexus of fourth
ventricle
lateral
aperature
Fourth ventricle
Medulla
oblongata
Median aperature
Spinal cord
Central canal
Note: * midbrain includes corpora quadrigemina (posterior portion of mid-brain) and cerebral peduncles
(anterior section of mid-brain line in front of the cerebral aqueduct)
Figure 17.
Diagram of mid-sagittal section of the brain
Figure 18.
MRI scan - Mid-sagittal section of the brain
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To obtain a mid-sagittal section of the brain a cut is made between the two
cerebral hemispheres. This cut divides the midline structures that connect the
two hemispheres as well as other midline structures such as the cerebellum and
brain stem.
When we look at the section, the hemispheres are intact and we can identify the
gyri and sulci of the hemispheres and the frontal, parietal and occipital lobes.
The temporal lobe is just visible anterior to the pons but it is a lateral structure –
it does not lie in this plane.
The cut surface of the corpus callosum is very prominent (note its appearance on
the MRI scan) – this large structure consists of commissural fibres (white matter)
carrying information between the hemispheres.
The third ventricle is a midline structure – choroid plexus in the third ventricle
is visible.
On either side of the third ventricle lies the thalamus.
Identify the pineal gland.
The hypothalamus lies below the thalamus and from this the infundibulum
leads to the pituitary gland.
In this region the optic chiasm is also found.
Identify the cerebral aqueduct leading to the fourth ventricle – there is choroid
plexus visible in the fourth ventricle as well.
Identify the midbrain structures – the cerebral peduncles and corpora
quadrigemina.
Note that the pons and the majority of the medulla oblongata lie anterior to the
cerebral aqueduct.
Identify the cerebellum – note its position relative to the cerebral aqueduct and
the occipital lobe. What separates these two structures?
Although we have been able to identify many of the structures of the brain on
this section, there are structures that lie lateral to this plane that are not seen.
One way to display these structures would be to look at other sagittal sections.
For example:
The lateral ventricles and the basal ganglia are not seen on a mid-sagittal section
but would be seen on para-sagittal sections. Other sections such as transverse
and coronal sections can also be used to display these structures. However, as
we will see, these sections will not display the full extent of a lateral ventricle as
well as para-sagittal sections.
As we look at these other sections we need to keep referring to the mid-sagittal
section to help up with the anterior/posterior and superior/inferior
relationships of the structures.
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Transverse Sections of the Brain
The next three sections are transverse sections taken through the brain at the
level indicated in the small diagram.
Interhemispheric
fissure
Fat in scalp
Fat in diploic space
Cerebral grey matter
Cerebral white matter
Anterior portion of body
of corpus callosum
Body of lateral
ventricle
Posterior portion of body
of corpus collosum
Interhemispheric
fissure
Superior sagittal
sinus
Figure 19a.
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MRI scan - Transverse section of the brain
This section displays the inter-hemispheric fissure – identify the superior sagittal
sinus at the posterior end.
The grey matter (cell bodies) of the hemispheres is clearly visible – identify a
frontal gyrus and sulcus.
Identify the frontal, parietal and occipital lobes.
Identify cerebral white matter (nerve fibres) – some of the nerve tracts are
association fibres connecting nerve cells in the same hemisphere – some are
commissural fibres (eg the corpus callosum) connecting nerve cells in the
opposite hemisphere.
This section cuts through the superior portion of the body of the lateral
ventricles – the true size of the ventricles cannot be appreciated in this section.
Figure 19b. Transverse slice of normal HMPAO Brain SPECT study
23
Interhemispheric
fissure
Genu of corpus callosum
Frontal horn of
lateral ventricle
Septum pellucidum
Internal capsule
Insula in sylvian fissure
Thalamus
Head of caudate nucleus
Foramen of Munro
Putamen
Globus pallidus
Pulvinar of thalamus
Tail of caudate nucleus
position of Pineal gland
Trigone of lateral
ventricle
Superior sagittal sinus
Figure 20a.
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MRI scan -Transverse section of the brain
This section is inferior to the one above and cuts through the frontal and
posterior horns of the lateral ventricles – again the true size of these structures
cannot be appreciated on this section.
Identify the septum pellucidum – the structure that separates the two frontal
horns of the lateral ventricles.
Note the foramen of Munro/interventricular foramen which are the openings
which connect the lateral ventricles to the third ventricle and through which
Cerebral Spinal Fluid (CSF) passes.
Note that only the most superior portion of the third ventricle is seen here – as
it is an inferior structure it will be seen on the next section.
Identify the genu of the corpus callosum.
Note the spaces filled with CSF appear dark on the MRI image – identify the
subarachnoid space and superior cistern as well as the ventricles.
Identify the thalamus which lies either side of the third ventricle.
Note that the pineal gland which is at the posterior portion of the thalamus
should appear to be “floating in CSF” in this particular section.
Identify the nuclei – masses of grey matter – which are part of the basal ganglia
– the caudate nucleus, putamen and globus pallidus.
Again identify which lobes of the hemispheres are visible.
Note the Insula lobe.
Figure 20b. Transverse slice of normal HMPAO Brain SPECT study
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Eyeball
Orbital fat
Optic nerve
Temporal lobe
Upper pons
Cerebral vermis
Cerebellar hemisphere
Superior cerebral
peduncle
Fourth ventricle
Transverse (lateral)
venous sinus
Figure 21a.
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MRI scan - Transverse section of the brain
This section is made at the base of the brain.
Note that the section is below the frontal lobe and only the temporal lobes are
still seen.
The vermis and hemispheres of the cerebellum occupy the posterior fossa.
Identify the fourth ventricle.
Identify the pons.
Note the cisterns and subarachnoid space filled with CSF.
Identify the optic nerves – in a superior section the optic chiasm would have
been visible.
Figure 21b. Transverse slice of normal HMPAO Brain SPECT study
25
Coronal Sections of the Brain
Refer to figure 22 which is a diagram of a coronal section of the brain to assist
you with localising structures on the coronal MRI scans. The diagram is at
approximately the same level as the second MRI scan.
Cerebrum
Corpus callosum
Lateral ventricle
Thalamus
Caudate nucleus
Corpus
stratium
Putamen Lentiform
Globus
nucleus
pallidus
Third ventricle
Insula
Hypothalamus
Claustrum
Internal
capsule
Optic
tract
Adapted from:
Figure. 22
Infundibulum
Pituitary gland
Principles of Anatomy and Physiology
Tortora and Anagnostakos
Publisher John Wiley 1999 ISBN: 0471378011
Diagram of coronal section of the brain
Note !
Note that a coronal section gives a better appreciation of superior/inferior
relations – the third ventricle can be seen below the lateral ventricles, the lateral
sulcus can be clearly seen dividing the parietal lobe from the temporal lobe. The
position of the thalamus on either side of the third ventricle is seen as well as the
hypothalamus which is inferior to the thalamus.
The next three figures are coronal sections taken at the level indicated in the
small diagrams.
26
Superior
sagittal sinus
Frontal gyrus
Interhemisphere
fissure
White matter of
Frontal lobe
Corpus Callosum
Frontal horn of
lateral ventricle
Cingulate sulcus
Caudate nucleus
Insula
Sylvian fissure
Branches of the
middle cerebral artery
Temporal lobe
Figure 23a.
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MRI scan - Coronal section of the brain
Note the grey matter and white matter – identify gyri, sulci and cerebral white
matter.
Note the interhemispheric fissure – what structures lie within this fissure?
Identify all the lobes of the cerebrum visible on this section.
Locate the corpus callosum.
Identify the lateral ventricles – which part of these structures is visible here?
Identify the lateral/sylvian fissure – what structure lies within this fissure?
Branches of what major artery are found in the lateral fissure?
Figure 23b. Coronal slice of normal HMPAO Brain SPECT study
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Parietal lobe
Interhemispheric
fissure
Body of lateral
ventricle
Caudate nucleus
Thalamus
Sylvian fissure
Third ventricle
Temporal lobe
Cerebral Peduncle
Pons
Figure 24a.
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MRI scan - Coronal section of the brain
Identify structures noted on the previous slice – have any structures/areas
disappeared?
Identify the lobes of the cerebrum visible on this section.
What portion(s) of the lateral ventricles are now visible?
Identify the third ventricle – what structure lies on either side of the third
ventricle?
Note the caudate nucleus (part of the basal ganglia).
Identify the hippocampus in the temporal lobe
Identify the pons.
Figure 24b. Coronal slice of normal HMPAO Brain SPECT study
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Superior
sagittal sinus
Parietal lobe
Falx cerebri in
interhemispheric fissure
Straight sinus
Supracerebellar
cistern
Occipital horn of
lateral ventricle
Tentorium cerebelli
Cerebellum
Occipital lobe
Figure 25a.
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Identify structures noted on the previous slice – have any structures/areas
disappeared?
Identify the cerebral lobes present in the section
Identify the falx cerebri in the interhemispheric fissure – what structures lie at
the superior and inferior parts of this structure.
Identify the tentorium cerebelli.
What part of the lateral ventricles are visible (or are supposed to be visible –
they are a little difficult to see)?
Identify the cerebellum.
Identify the CSF filled cistern above the cerebellum
Figure 25b.
Note:
MRI scan - Coronal section of the brain
Coronal slice of normal HMPAO Brain SPECT study
All the 99mTc- HMPAO Brain SPECT images displayed are an average of normal
brain SPECT studies performed on 22 females. The slices displayed are as close
as possible to the MRI scan sections displayed.
29
Go to your Workbook Sectional Anatomy and complete question 3
Summary
The aim of Part 1 of the Unit has been to start you thinking about anatomy in a
different way – you should now be thinking in terms of how organs relate to one
another in three dimensional space. This has only been an introduction to the
subject - hopefully enough so that you will start looking at CT or MRI scans as
well as your SPECT images with greater understanding.
Good
Idea!
The more you practice looking at images in this way the easier it will be become.
Nuclear Medicine imaging in the future will probably involve more sectional
imaging using radiopharmaceuticals that localise in a number of tissues.
Sectional anatomy and the type of thinking it involves will become more
important if we are to use our technology to the maximum benefit of the patient.
We will probably also need to become more involved with correlating our
SPECT and PET images with CT and MRI images.
An Exercise on familiarity with Cross Sectional Anatomy
Go to the internet.
Now that you have completed the exercises in this Unit and are familiar with
various anatomical cross sectional slices for SPECT, CT and MRI, you should
access the internet and visit the following websites for further experience in
viewing transverse, sagittal and coronal images. The black and white images
within the text of this Unit has a limited teaching capacity but you can
appreciate the subject further through visual and interactive experience on the
computer.
Good examples to try:
http://www.med.harvard.edu/AANLIB/home.html
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This is an information resource for the central nervous system with normal and
pathologic structure images, and multiplanar and vascular anatomy which
integrates clinical information with MR, CT, and nuclear medicine SPECT and
PET images. The atlas covers Cerebrovascular, Neoplastic, Degenerative and
Inflammatory or Infectious Diseases. The project is made possible in part by the
Departments of Radiology and Neurology at Brigham and Women's Hospital,
Harvard Medical School, the Countway Library of Medicine, and the American
Academy of Neurology
http://www.lumen.luc.edu/lumen/meded/grossanatomy/x_sec/mainx_sec.htm
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This site provides cross sectional CT and MRI interactive images of head and
neck, thorax, abdomen, pelvis and upper and lower limb. You can choose your
anatomical region and level of cross sectional slice, with or without labels and
even test your knowledge. This anatomical atlas is provided by LUMEN CrossSection Tutorial as developed through Loyola University Chicago Stritch School
of Medicine.
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Other websites of interest include:
http://www.anatomyatlases.org/HumanAnatomy/CrossSectionAtlas.shtml
http://teaching.anatomy.auckland.ac.nz/atlas/abdomenthorax/intro/images.htm
Go to your Workbook Sectional Anatomy and complete question 4
Key Points
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Sagittal sections give information about the anterior/posterior and
superior/inferior relationship of structures.
Coronal sections give information about superior/inferior relationships of
structures and medial/lateral relationships.
Transverse or axial sections give information about anterior/posterior
relationships and medial/lateral relationships.
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Part 2
Introduction:
Now that you have completed Part 1 you will be familiar with the terminology
associated with cross sectional anatomy when describing the various planes at
which images are projected. You have studied labelled diagrams depicting the
sections of internal organs at different levels of the brain, thorax and pelvis and
completed exercises recording your understanding of these features.
With the fusion of SPECT and PET images with CT, we now need to broaden our
understanding towards what we expect to visualize in normal PET/CT image
and learn to distinguish normal anatomic variations from variations that indicate disease or injury.
The Units: Clinical PET, SPECT and PET Physics and Principles of CT all
emphazise the importance of quality assurance and how to avoid errors and
misinformation.
Variants and Pitfalls teaches you how to recognise normal variations and
provides image examples of what can be seen if certain artefacts are experienced.
When considering these aspects you are betters able to recognise abnormalities
but first you need to be familiar with normal structures, organs and vessel
locations and expected uptake of radiopharmaceuticals.
DAT Cross Sectional program: website:…… This new learning resource is rich in features making it easier for you to learn, identify, and recall anatomic structures in cross‐section. You can step through
the transverse, coronal and sagittal slices of normal FDG PET scans and
associated CT or MRI images shown in sequence through multiple planes allowing you to identify anatomy on actual images through labels of important
sites of interest within the brain, thorax and pelvis. There are self-assessment
questions to test your understanding with feedback answers. At the completion
of this exercise you should complete the assignment of Multiple Choice
Questions. The results will be recorded as part of you final assessment.
Objectives:
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On completion of the on-line exercise you will be able to
Identify…
Recognise…
Time Check:
Allow 6 hrs to complete this exercise on_line through the DAT website
First perform the following Familiarity exercise:
Go to:
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http://www.med.harvard.edu/JPNM/chetan/
Try the various options:
Normal Distribution
Benign Pathological Variants
Pitfalls and Artefacts
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Prepare for an Exercise
Go To your computer and log_on to the DAT website……
Enter your password ….
Follow instructions ………………..
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