Chapter 2:
Terms Pertaining to the
Body as a Whole
Tri-State Business Institute
MD000 Medical Terminology 1
Micheal H. McCabe, EMT-P
Structural Organization of
the Body:
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The cell is the fundamental unit of all
living things.
All cells have a similar structure.
Cells are everywhere in the body –
every organ and tissue is composed of
cells.
The study of cells is called cytology.
The study of tissues is called histology.
Parts of the Cell:
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[1] Cell Membrane – surrounds and
protects the cell. Also Regulates what
passes into and out of the cell.
[2] Nucleus – is the control center of
the cell. Genetic material in the
nucleus determines the structure and
function of the cell and controls
reproduction.
Parts of the Cell:
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[3] Chromosomes are rod-like structures
within the nucleus. Most human cells
contain 23 paired chromosomes that
comprise the human genome.
Chromosomes contain regions called genes.
Each gene is built up of DNA. The DNA
serves as a chemical “program” that directs
the function of the cell.
Parts of the Cell:
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[4] Cytoplasm is all the material
outside the nucleus and enclosed by
the cell membrane. It includes
intracellular fluid as well as discrete
structures like the mitochondria[a],
endoplasmic reticulum[b], and
ribosomes.
Mitochondria:
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Small, sausage-shaped bodies found in
the cytoplasm.
Mitochondria are the “power-plants”
within the cell that produce energy by
combining food with oxygen.
This chemical process is called
catabolism.
Endoplasmic Reticulum:
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Is a network of canals (reticulum)
within the cell.
The endoplasmic reticulum (ER)
contains very small structures called
ribosomes that manufacture protein.
This chemical process is called
anabolism.
Metabolism:
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Metabolism is the total of the chemical
processes within the cell.
Metabolism includes catabolism and
anabolism.
If a person has a “fast” metabolism,
nutrients are used up quickly and energy is
released.
If a person has a “slow” metabolism,
nutrients are used slowly and fat
accumulates in the cells.
Karyotype:
Karyotype:
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A karyotype is a photographic “map”
of the chromosomes.
The chromosomes are treated with
chemicals so that light and dark areas
are visible.
An electron microscope is used to
visualize and photograph the
chromosomes.
Amniocentisis:
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This procedure is undertaken to check an
unborn baby for chromosomal
abnormalities.
A needle is used to aspirate a quantity of
cells from the amniotic sac.
A karyotype is created from the aspirated
cells.
This is a prenatal test frequently used to
diagnose Down’s Syndrome.
Study Section 1:
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Anabolism – the process of building up
complex materials (proteins) from
simple materials.
Catabolism – the process of breaking
down complex materials (foods) to
form simpler substances and release
energy.
Study Section 1:
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Cell Membrane – Structure surrounding and
protecting the cell. It determines what
enters and leaves the cell.
Chromosomes – rod-shaped structures in
the nucleus that contain regions of DNA
called genes. There are 46 chromosomes
(23 pairs) in most human cells.
Cytoplasm – all the material that is outside
the nucleus yet contained within the cell
membrane.
Study Section 1:
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DNA – deoxyribonucleic acid; chemical
found in each chromosome. Arranged
like a sequence of recipes in code, it
directs the activities of the cell.
Endoplasmic Reticulum – Structures
(canals) within the cytoplasm. Site in
which large proteins are made from
smaller pieces (amino acids.)
Study Section 1:
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Genes – regions of DNA within each
chromosome.
Karyotype – Picture of chromosomes
in the nucleus of a cell. The
chromosomes are arranged in
numerical order to determine their
number and structure.
Study Section 1:
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Metabolism – The total of the chemical
processes in a cell. It includes both
catabolism and anabolism.
Mitochondria – Sausage-shaped
structures in the cytoplasm in which
foods are burned to release energy;
“power plants.”
Study Section 1:
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Nucleus – Control center of the cell. It
contains chromosomes and directs the
activities of the cell.
Differences in Cells:
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Cells throughout the body are
specialized to perform particular tasks.
A group of similar cells working
together to do a specific job is called a
tissue.
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A specialist who studies tissues is
called a histologist.
Some Types of Cells:
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Muscle Cells – are long, slender, and contain
contractile fibers that allow them to shorten
their length.
Epithelial Cells – are specialized cells that
form protective membranes like the skin.
Nerve Cells – are very long and have various
fibrous extensions that aid its job of carrying
impulses.
Fat Cells – contain large empty spaces for
fat storage.
Diagrams of Cell Types:
Epithelial Tissue:
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Epithelial Tissue – is located throughout the
body and forms the lining of internal organs,
makes up exocrine and endocrine glands,
and forms the outer surface of the skin
covering the body. The word epithelial was
originally used to describe the tissue above
the breast nipple. Now it is used to
describe the tissues that cover the outside
of the body and line the internal cavities.
Muscle Tissue:
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Voluntary muscle is found attached to the skeleton.
It allows voluntary movement under conscious
control.
Involuntary muscle (smooth muscle) is found in the
walls of the blood vessels, intestines, and hollow
organs of the body. This movement is not under
conscious control.
Cardiac Muscle is found only in the walls of the
heart (myocardium) and is specialized in that it will
contract automatically – independent of nervous
system action. This property is called automaticity.
Connective Tissue:
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Connective tissue is the most common
and the most diverse of all body
tissues.
Examples are fat (adipose tissue),
bone, cartilage, and blood.
Connective tissue is characterized by
relatively few cells that create noncellular structures known as matrix.
Nerve Tissue:
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Nerve tissue conducts impulses all over the body.
Nerve cells have specialized extensions called axons
and dendrites that serve as specialized
communication lines.
The Axon carries messages (impulses) away from
the body of the nerve cell. It serves as a
transmitter. Each nerve cell has only one axon.
Dendrites carry messages (impulses) towards the
body of the cells. They serve as receivers. Each
nerve cell can have many dendrites.
Organs:
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Organs are structures composed of several
kinds of tissue.
For example, the stomach is composed of
muscle tissue, nerve tissue, glandular
epithelial tissue, and connective tissue.
The medical term for internal organs is
viscera (singular form: viscus)
Examples of abdominal viscera include the
liver, stomach, pancreas, intestines, spleen,
and gallbladder.
Systems:
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Systems are groups of organs working
together to perform complex
functions.
Different books and authors group the
organ systems differently.
Example: This book groups the body
into ten body systems. The A&P class
groups the body into 15 systems.
Digestive System:
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Function is to digest food, absorb
nutrients into the bloodstream, and
eliminate solid waste.
Organs include the mouth, pharynx,
esophagus, stomach, intestines, liver,
gallbladder, and pancreas.
Urinary System:
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Also called the excretory system.
Function is to eliminate metabolic
waste, maintain the fluid balance of
the body, regulate electrolyte levels,
and govern the acid/base balance.
Organs include the kidneys, ureters,
bladder, and urethra.
Respiratory System:
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Function is to bring oxygen into the
bloodstream and eliminate carbon
dioxide. Also helps regulate the
acid/base balance.
Organs include the nose, pharynx,
larynx, trachea, bronchi, bronchioles,
and lungs.
Reproductive System:
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Function is to enable reproduction of the
entire organism and to help perpetuate the
species.
Organs differ somewhat between males and
females.
Male organs include the testes and assorted
tubes, urethra, prostate gland, and penis.
Female organs include the ovaries, fallopian
tubes, uterus, vagina, and mammary
glands.
Endocrine:
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Function is of a chemical
communication system that regulates
function and metabolism at a cellular
level.
Organs include the pituitary gland,
thyroid gland, sex glands (gonads),
adrenal glands, parathyroid gland,
thymus, and the pancreas.
Nervous System:
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Function is complex – includes
command, control, and communication
throughout the entire body.
Organs include the brain, spinal cord,
cranial nerves, spinal nerves, and
other collections of nerve structures.
Circulatory System:
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Functions as a transportation system – used
to move oxygen, nutrients, waste products,
carbon dioxide, chemicals, hormones, and
immune system components throughout the
body.
Organs include the heart, blood vessels,
lymphatic vessels and nodes, blood, lymph,
spleen, and thymus gland.
One of the more complex systems we will
discuss.
Muscular System:
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Function is to enable movement:
skeletal muscles move the body itself;
smooth muscles move substances
within the body; cardiac muscle
enables operation of the circulatory
system.
Organs include more than 600 muscles
and tendons.
Skeletal System:
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Provides supporting framework for the
body; also protects internal organs
and provides for movement via its
articulations.
Includes more than 200 bones plus
ligaments, cartilage, and joint
structures.
Skin and Sense Organs:
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The skin provides an overall covering
for the body.
Accessory organs of the skin include
hair and nails.
General sense organs are embedded
within the skin.
Special sense organs are complex
independent structures.
Study Section 2:
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Adipose tissue – collection of fat cells.
Cartilage – flexible connective tissue
attached to bones at joints.
Epithelial Cell – skin cells that cover
the external body surfaces and line the
internal surfaces of organs.
Histologist – a specialist in the study
of tissues.
Study Section 2:
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Larynx – voice box; located at the
upper part of the trachea.
Pharynx – throat; The pharynx is the
common passageway for food and air
entering the body.
Pituitary gland – Endocrine gland
located at the base of the brain.
Study Section 2:
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Thyroid gland – endocrine gland that
surrounds the trachea in the neck.
Trachea – The windpipe – a tube
leading from the throat to the bronchi.
Ureter – One of two tubes leading
from each kidney to the urinary
bladder.
Study Section 2:
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Urethra – Tube from the urinary
bladder to the outside of the body.
Uterus – The womb. The organ that
holds the embryo and fetus as it
develops.
Viscera – internal organs.
Body Cavities:
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A body cavity is a space within the
body that contains internal organs
(viscera.)
Ventral cavities are found in the front
of the body.
Dorsal cavities are found in the back.
Body Cavities:
Ventral Cavities:
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Thoracic Cavity – Located in the upper
half of the torso (thorax); the
diaphragm separates the thoracic
cavity from the abdominal cavity.
Abdominal Cavity – located in the
middle portion of the torso (abdomen)
Pelvic Cavity – located within the
pelvic girdle.
Dorsal Cavities:
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Cranial Cavity – lies within the cranial
vault; the hollow, enclosed portion of
the skull.
Spinal Cavity – lies within the
vertebrae. Also called the vertebral
canal.
The Cranial Cavity:
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Contains the brain and pituitary gland.
Is lined by the meninges surrounding
the brain.
Regions of the cranial cavity (and the
brain within) are named after adjacent
bones (occipital, frontal, parietal,
temporal, etc.)
The Thoracic Cavity:
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Contains the heart, lungs, esophagus,
trachea, bronchial tubes, thymus glad,
aorta, and other large blood vessels.
Can be divided into two smaller cavities:
1. Pleural Cavity – space between the
membranes that surround each lung.
2. Mediastinum – a centrally located area outside
of and between the lungs. Contains the heart,
aorta, trachea, esophagus, thymus gland,
bronchi, and many lymph nodes.
Divisions of the Thoracic
Cavity:
The Abdominal Cavity:
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Contains the stomach, small intestine,
large intestines, spleen, pancreas,
liver, and gallbladder.
Lined by a double folded membrane
called the peritoneum.
Behind the peritoneum is the
retroperitoneal space where the
kidneys are located.
The Abdominal Cavity:
The Pelvic Cavity:
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Located within the pelvic girdle.
Some authors consider this part of the abdominal
cavity. May refer the collective space as the
abdominopelvic cavity.
Contains portions of the large and small intestine,
the rectum, urinary bladder, ureters, urethra.
In the female, also contains the uterus and vagina.
In the male, also contains the prostate gland.
Most pelvic organs not enveloped by the
peritoneum.
The Spinal Cavity:
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Located within the vertebral column.
Also called the spinal canal.
Contains the spinal cord and spinal
nerves.
Study Section 3:
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Abdominal Cavity – space below the chest
containing organs such as the liver,
stomach, gallbladder, and intestines; also
called simply the abdomen.
Cranial Cavity – space in the head
containing the brain and surrounded by the
skull. Cranial means “pertaining to the
skull.”
Study Section 3:
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Diaphragm – muscle separating the
abdominal and thoracic cavities.
Dorsal (posterior) – pertaining to the back.
Mediastinum – Centrally located between
the lungs.
Pelvic Cavity – Space below the abdomen
containing portions of the intestines,
rectum, urinary bladder, and reproductive
organs. Pelvic means “pertaining to the hip
bone,” which surrounds the pelvic cavity.
Study Section 3:
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Pleura – a double-layered membrane
surrounding each lung.
Pleural Cavity – Space between the pleural
membranes and surrounding each lung.
Spinal cavity – Space within the spinal
column (backbone) and containing the
spinal cord. Also called the spinal canal.
Study Section 3:
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Thoracic Cavity – Space in the chest
containing the heart, lungs, bronchial
tubes, trachea, esophagus, and other
organs.
Ventral (Anterior) – Pertaining to the
front.
Organs of the Abdomen
and Thorax:
Organs of the Abdomen and
Thorax (Posterior View):
Regions of the Abdomen:
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The combined abdominal and pelvic
cavities are divided into nine regions.
These regions are used by doctors to
describe the location where various
organs are found.
These regions are frequently used in
reports describing the location of pain
and surgical procedures.
Regions of the Abdomen:
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Hypochondriac – two upper left and upper
right regions below the cartilage of the ribs
that extend over the abdomen.
Epigastric Region – The region above the
stomach.
Lumbar Region – two middle right and
middle left regions near the waist.
Umbilical Region – area of the navel
(umbilicus)
Regions of the Abdomen:
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Inguinal Regions – two lower right and left
regions near the groin, where the legs join
the trunk of the body. These regions are
also known as the iliac regions because they
are near the ilium which is the upper portion
of the hip bone on each side of the body.
Hypogastric Region – lower middle region
below the umbilical region.
Regions of the Abdomen:
Abdominal Quadrants:
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The abdominopelvic area can be
divided into four quadrants by drawing
two imaginary lines – one horizontally
and one vertically through the body.
Right Upper Quadrant (RUQ) contains
the liver, gallbladder, part of the
pancreas, and parts of the large and
small intestine.
Abdominal Quadrants:
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Left Upper Quandrant (LUQ) –
contains the liver, stomach, spleen,
part of the pancreas, and parts of the
large and small intestine.
Right Lower Quadrant (RLQ) –
contains parts of the small and large
intestine, right ovary, right fallopian
tube, appendix, and right ureter.
Abdominal Quadrants:
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Left Lower Quadrant – contains part of
the large and small intestines, left
ovary, left fallopian tube, and left
ureter.
Abdominal Quadrants:
Divisions of the Back:
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The back is divided into divisions that
correspond to the regions of the spinal
column.
The spinal column is composed of a
series of small bones that extend from
the neck to the tailbone.
Each bone is called a vertebra (plural:
vertebrae.)
Divisions of the Back:
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Cervical (abbrev. C) – Neck region. There
are 7 cervical vertebrae. (C1-C7)
Thoracic (abbrev. T) – Chest region. There
are 12 thoracic vertebrae (T1-T12). Each
vertebra is joined to a rib.
Lumbar (abbrev. L) – Loin (waist) or flank
region. There are 5 lumbar vertebrae. (L1L5)
Divisions of the Back:
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Sacral (abbrev. S) – Joined to posterior
pelvic girdle. There are five bones
(S1-S5) fused into one, the sacrum.
Coccygeal – The coccyx (tailbone) is a
small bone composed of four fused
pieces.
Spinal Column V. Spinal
Cord:
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Do not confuse the spinal column with
the spinal cord!
The spinal column is bone tissue and
the spinal cord is nerve tissue.
Intervertebral Discs:
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The spaces between the vertebrae are identified
according to the two vertebrae between which they
lie.
For example, L5-S1 lies between the 5th lumbar and
1st sacral vertebrae.
Within the space and between vertebrae there is a
small piece of cartilage called a disc.
The disc acts as a shock absorber.
Occassionally, it moves out of place (ruptures) and
puts pressure on a nerve. This is called a “slipped
disc,” and can be very painful.
Study Section 4 –
Abdominopelvic Regions:
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Hypochondriac – upper right and left
regions beneath the ribs.
Epigastric – upper middle region above
the stomach.
Lumbar – Middle left and right regions
near the waist.
Umbilical – Central region around the
navel.
Study Section 4 –
Abdominopelvic Regions:
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Ingiunal – Lower right and left regions
near the groin. Also called the iliac
regions.
Hypogastric – Lower middle region
below the umbilical region.
Study Section 4 –
Abdominopelvic Quadrants:
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RUQ – Right Upper Quadrant
LUQ – Left Upper Quadrant
RLQ – Right Lower Quadrant
LLQ – Left Lower Quadrant
Study Section 4 –
Divisions of the Back:
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Cervical – Neck region (C1-C7)
Thoracic – Chest Region (T1-T12)
Lumbar – Waist Region (L1-L5)
Sacral – Region of the sacrum (S1-S5)
Coccygeal – Region of the tailbone
Study Section 4 – Related
Terms:
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Vertebra – A single back bone
Vertebrae – Plural form of vertebra
Spinal Column – Bone tissue
surrounding the spinal cavity.
Spinal Cord – Nervous tissue within
the spinal cavity
Disc (disk) – A pad of Cartilage
between vertebrae.
Positional and Directional
Terms:
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Anterior (Ventral) – Front side of the body.
Ventral and anterior are the same in
humans (we walk upright!); in an animal
(on four legs), ventral refers to the belly
side and anterior to the front end near the
head.
Posterior (Dorsal) – The back side of the
body; opposite of anterior. Also different in
quadrapeds.
Positional and Directional
Terms:
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Deep – away from the surface.
Superficial – on (or near) the surface.
Positional and Directional
Terms:
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Proximal – Near the point of
attachment to the trunk or near the
beginning of a structure.
Distal – Far from the point of
attachment
Positional and Directional
Terms:
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Inferior – Below another structure.
The term caudal (pertaining to the
tail) also means inferior in humans.
Superior – Above another structure.
The term cephalic (pertaining to the
head) is also used to mean superior.
Positional and Directional
Terms:
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Medial – In the middle or nearer the
medial plane of the body.
Lateral – Pertaining to the side –
farther away from the midline.
Positional and Directional
Terms:
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Supine – Lying on the back.
Prone – Lying on the belly.
Planes of the Body:
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A plane is an imaginary flat surface.
Frontal (Coronal) – a vertical plane that
divides the body into anterior and posterior
portions. Also called a coronal plane.
Sagittal (Lateral) – a lengthwise vertical
plane that divides the body or structure into
left and right sides. The midsagittal plane
divides the body or structure equally in half.
Transverse – Plane running across the body
parallel to the ground (horizontal.) Also
called a cross-sectional plane.
Anatomical Directions
and Planes of the Body:
Study Section 5:
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Anterior (Ventral) – Pertaining to the
front (belly side) of the body.
Deep – away from the surface
Distal – far from the trunk or far from
the beginning of a structure
Frontal (Coronal) Plane – vertical plane
dividing the body into anterior and
posterior portions.
Study Section 5:
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Inferior (caudal) – Below another
structure.
Lateral – pertaining to the side.
Medial – pertaining to the middle or
near the medial plane of the body.
Posterior (dorsal) – Pertaining to the
back of the body.
Study Section 5:
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Prone – lying on the belly (face down)
Proximal – Near the point of
attachment to the trunk or near the
beginning of a structure
Sagittal Plane – Vertical, lateral plane
diving the body into left and right
sides.
Study Section 5:
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Superficial – on the surface
Superior (cephalic) – above another
structure
Supine – lying on the back (face up,
palm up)
Transverse Plane – Horizontal plane
dividing the body into upper and lower
portions.