ANATOMY AND POSITIONS
The study of the human body is divided into two basic branches of science:
•
•
Anatomy, which deals with the physical structures that make up the body and the
way these structure interact.
Physiology, which deals with how the body structures work and what functions they
perform.
The human body, as a structure, can be broken down into levels of organisation. The
simplest level is the chemical level. This is followed by the most basic level, the cell level.
Groups of cells make up the tissue level. The same type of body tissue grouped together
forms the organ level, and groups of organs make up the system level.
Cells
Tissues
Organs
Systems
Chemical
The simplest level of the structural hierarchy is the chemical level.
Atoms - tiny building blocks of matter, combine to form molecules such as water,
sugar and proteins.
Molecules - associate in very specific ways to form microscopic cells.
Cells
Cells are the basic structural and functional building blocks of the body. Among the many
different kinds of cells in your body are muscle cells, nerve cells arid blood cells. The
combining form for cell is cyt/o or at the end of a word (the suffix ) as -cyte.
pathology
patho (combining form indicating disease or suffering)
logy (study of)
=study of disease
cellular pathology = pathology that is related to microscopic changes in body cells
chemical pathology = study of chemical changes that occur in disease
cytology
cyt
(root word) = cell
o
(combining vowel)
logy (suffix) = study of
= study of cells
Cytology is an important topic in medicine as many diseases and disorders can be
diagnosed by studying cells.
Cytopathy
Reading from the suffix back = disease of cells
Anatomy and Positions
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Activity 6.1
1.
1.
2.
3.
4.
5.
2.
Write the definition of the following words:
Word
cellular
1
cytology
2
cytologist
3
cytopathology
4
pathology
5
Meaning
Make up a word that means:
Meaning
6. A white cell use leuc/o for white, and the ending -cyte
7. A Sred cell use erythr/o for red, and the -cyte ending)
8. A 6disease of cells (use -pathy for disease)
9. A bone cell
10. A lymph cell
Word
Tissues
Tissues are made up of types of cells which are similar in origin, appearance and
function. The four basic types of tissue are:

Connective tissue - this tissue works, as its name suggests, supporting body
structures and connecting to other tissues. Connective tissue includes fat tissue,
and bone tissue.
Epithelial tissue - this tissue makes up our skin and also forms a protective lining in
organs such as the stomach.
Muscle tissue - this tissue makes up our muscles
Nerve tissue - this makes up parts of the nervous system.



The combining form for tissue is hist/o.
Activity 6.2
Write the definition for the following words:
1.
2.
3.
4.
5.
Word
histology
histologist
histopathology
histolysis
histochemistry
Anatomy and Positions
Meaning
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Organs
When two or more different types of tissue are joined together, they form a more
complex level of organisation: the organ level. Organs are structures composed of
several types of tissue. Organs have a recognisable shape and perform special
functions. Organs include the heart, liver, lungs, brain and stomach,
Systems
A system consists of a group of organs working together to perform a particular function.
Body systems include:









The digestive system
The skeletal system
The muscular system
The nervous system
The cardiovascular system
The respiratory (or pulmonary) system
The urinary system
The reproductive system
The integumentary (or skin) system
SURVIVAL NEEDS
The ultimate goal of nearly all body systems is to maintain life. However life is extremely
fragile and requires several factors acting together for its persistence. These factors, or
survival needs, include:
Food (nutrients)-which contain the chemical substances used for energy and cell
building:
Plant derived food - rich in carbohydrates, vitamins and minerals
Animal food - protein and fats
Carbohydrates are the major energy food for body cells.
Oxygen - required to release the energy from food. 20% of the air we breathe is oxygen.
Water - 60 - 80% of body weight, provides the liquid environment necessary for chemical
reactions.
Body temperature - must be maintained around 37 degree C.
too low -- physiological reactions slow
too high - physiological reactions increase too rapidly - both lead to death.
Atmospheric pressure - force exerted on the body so lungs work.
POSITIONS AND AREAS OF THE BODY
When the human body is described in medical terms, you should always image you are
looking at someone who is looking straight at you, with their arms straight and lifted
slightly away from the body, palms facing you, and their legs slightly apart. This is called
the anatomical position.
Anatomy and Positions
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THE POSITIONAL TERMS
When studying the different organs and systems of the body, it is important to be able to
describe accurately the location of their different structures. The following are terms used
to describe positions. They can be used to describe where a part of the body is, where a
surgical procedure took place, or where a wound was situated.
Term
Meaning
Example
Anterior
(or
ventral)
More to the front of the body than
another structure.
Describing the front part or surface
of the body, limbs, or an organ.
The sternum is anterior to the heart.
The umbilicus is on the anterior
surface of the body.
Posterior
(or dorsal)
More to the back of the body than
another structure.
Describing the back part or
surface of the body, limbs or an
organ
The spinal column is posterior to the
abdomen.
The heel is in the posterior section of
the foot
Central
Close to the middle or centre point.
The heart is located in the central
portion of the thoracic cavity.
Medial
Lateral
Peripheral
Deep
Superficial
Distal
Proximal
Inferior
Superior
Closer to the centre of the body or
an organ; towards the middle or
away from the side
Further away from the midline or
centre of the body or an organ;
away from the middle, towards the
side
Away from the centre point.
Away from the surface of the body
or an organ.
At, or close to, the surface of the
body organ.
Further away from the origin, point
of attachment or midline of the
body; further from a beginning
point, or nearer to an extremity
Closer to the origin, point of
attachment or midline of the body;
closer to a beginning point or
further from an extremity.
Lower in the body than another
structure or surface; away from the
head
Towards the head or above another
area
Internal
Inside the body or an organ.
External
Situated outside the body or an
organ.
Anatomy and Positions
The umbilicus is medial to the hips.
The hips are lateral to the umbilicus.
The limbs are peripheral to the body.
Deep blood vessels are those far
beneath the skin.
Superficial blood vessels are those
close to the surface of the skin.
The fingers are distal to the midline of
the body.
The shoulder is proximal to the midline
of the body.
The ankle is inferior to the knee.
The head is superior to the trunk
The cochlea is an internal part of the
ear.
The ear lobe is an external part of the
ear.
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Activity 6.3
1.
2.
3.
4.
5.
On your face what is superior to your nose?
On your leg what is inferior to your knee?
What is lateral to your left nipple?
What is proximal to your right knee?
What is distal to your left wrist?
Activity 6.4
Rewrite the following sentences using lay descriptions:
1.
2.
3.
4.
The dog bit the boy on the anterior section of his upper arm. The bites were
superficial and required no stitches.
A deep surgical incision was made in the lateral section of the LLQ, distal to naval.
The gall bladder is anatomically superior to the small intestine. It lies in a medial
position in the posterioinferior section of the liver.
The section of the small intestine, proximal to the stomach, was removed.
THE BODY DIRECTIONAL TERMS
The body can perform a variety of movements; medical professionals use a single term to
accurately define the specific movement. Common terms used include:
MOVEMENT TERMS
Term
Term
Meaning
Adduct
To draw towards
Efferent
Conducting towards
Flexion
Decreases the angle
Hyperextension
Meaning
To draw away
from
Conducting away
Increases the
angle
Over extension
Lateral rotation
To turn to the side
Pronation
Palm down
Supination
Palm up
Abduct
Afferent
Extension
Flexion
Flexion occurs when the angle of a joint is decreased. An example of flexion is to raise
your forearm towards your shoulder, bending at the elbow, or bringing the heel of your
foot towards your buttock, bending at the knee.
Extension
Extension occurs when the angle of a joint is increased. It is the opposite of flexion. If you
straighten your elbow or knee, you have examples of extension.
Anatomy and Positions
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Hyperextension
Hyperextension is the further increasing of the angle of a joint. Hold your hand out
straight from the wrist; this is extension. Now take your fingers with your other hand and
pull them back gently. This is hyperextension.
Abduction
Abduction means to move away from the midline. Stand with your arms by your side and
raise them laterally (sideways) out from your body. This is abduction.
Adduction
Adduction is the opposite of abduction. Bring your arms back towards your side and you
are adducting your arms.
EXTENSION
FLEXION
LATERAL ROTATION
Figure 3
Activity 6.5
Look at the figures above an answer the following questions:
1.
2.
3.
4.
5.
Which figure shows arms laterally abducted and extended at the elbow joint?
Which figure shows slightly abducted legs?
Which figure show hyperextension of the head?
In figure l, is her right arm flexed or extended at the elbow joint?
In figure 2, are her arms flexed or extended at the shoulder joint?
Anatomy and Positions
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Areas
To make it easier to find your way around the body, anatomists have divided the body
into areas. These areas have anatomical characteristics that are easily identifiable and
can serve as landmarks.
To begin with, the body is divided into different parts using imaginary lines or planes. For
example humans are bilaterally symmetrical - looking at the outside of the body, the left
and right sides are mirror images of each other. If you draw an imaginary vertical line
down the middle of the body, you have the first basic division: this is the midsagittal or
median plane that divides the body into left and the right sides. Any plane parallel to
the midsagittal or median plane is called a parasagittal or paramedian plane (para
meaning besides). The second plane is a horizontal cut which illustrates the horizontal
or transverse plane. This is the equivalent of a cross-section through the body dividing
it into upper (superior) or lower (inferior) sections. The third plane is a vertical cut
dividing the body into front (anterior) and back (posterior) sections at right angles to the
sagital and plane and is called the frontal or coronal plane
THE ANATOMICAL DIRECTIONAL TERMS
Directional terms indicate specific locations of the body.
Root word
anter, anteri
cephal (seFal)
dextr
proxim
super, superi
medi, mesi
ventr
Suffix
- ab
- or
- ad
- al
- ic
Meaning
before, front
head up, upward
right
near (the point of
reference)
above
middle
belly
Root word
poster, posteri
caud (kawd)
sinistr (sinist)
dist
infer, inferi
later
dors
Meaning
back, behind
tail, down, downward
left
away (from the point of
reference)
below
side
back
Meaning
toward
pertaining to (when used with directional
root words ending in i)
towards
pertaining to
pertaining to
The body is further divided into cavities or hollows. These are the places in the body
where major organs are situated.
l. The dorsal cavity is at the back of the body. The dorsal cavity is divided into two
smaller areas:
 The cranial or skull cavity that holds the brain, and the
 The spinal cavity, which holds the spinal cord
Anatomy and Positions
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2. The ventral cavity is at the front of the body is divided into three areas:



The thoracic cavity that holds the lungs and heart
The abdominal cavity, which contains the digestive organs, and the kidneys
The pelvic cavity, which holds the reproductive and the bladder
Activity 6.6
Identify which cavity contains the following organs:
Organs
1
Stomach
2
Lungs
3
Uterus
4
Brain
5
Spinal cord
Cavity
Abdominal quadrants
In medical reports, the abdomen is divided into four major areas. The best way to learn
these areas is to find them on your own body.
Activity 6.7
Lie in a supine position and find the bottom of your rib cage with your hands. Breathe in
and out and feel the diaphragm lifting and falling. The diaphragm is a massive muscle
that helps us breath. Below the diaphragm is your abdomen. It runs down to your hips.
Use your naval as the centre of your abdomen and trace a line down from the diaphragm
through the middle of your naval to the pubic bone. Now trace another line across the
middle of your abdomen, once again going through the naval. You have now divided the
abdomen into the four major regions used for medical reporting. These areas are called
the:




Right upper quadrant (RUQ)
Left upper quadrant (LUQ)
Right lower quadrant (RLQ)
Left lower quadrant (LLQ)
The quadrants are described left or right from the patient's perspective. As you lie on
your back, identify the four quadrants. Your stomach is in the LUQ. Your liver is in the
RUQ. Your appendix is in the RLQ. The LLQ contains part of the large intestine.
Activity 6.8
1.
2.
A patient rings complaining of a pain in their left upper quadrant, what organ may
be involved?
A patient rings complaining of a pain in their lower right quadrant which organ may
be effected?
Anatomy and Positions
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Self check questions
Give brief answers to the following questions
1.
2.
3.
4.
5.
6.
7.
8.
What medical word describes the physical properties of the body?
What word describes the functions of body structures?
What is the building block of the body?
What type of tissue supports and connects body structures?
Name three body organs
Name three body systems and their functions
Draw a sketch of a person in the anatomical position
If someone were lying in a supine position would they be on their side or on their
back?
9.
Is the dorsal cavity situated at the back or the front of the body?
10. What organs does the thoracic cavity hold?
11. What organs does the cranial cavity hold?
Answer true or false to the following statements
12.
13.
14.
15.
16.
17.
18.
Anterior means situated at the back of a structure
Distal means away from the beginning point
Peripheral means away from the beginning point
Superior means above
Inferior means above
Median means relating to the side
Lateral means pertaining to the side
Anatomy and Positions
T or F
T or F
T or F
T or F
T or F
T or F
T or F
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