Chapter 5:
Body Structure
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Chapter Objectives
 Main directional terms used in anatomy.
 Division of the body along three different planes.
 Dorsal and ventral body cavities.
 Nine divisions of the abdomen.
 Four quadrants of the abdomen.
 Main body positions used in medical practice.
 Basic terms describing body structure
 Roots pertaining to body regions.
 Prefixes pertaining to position and direction.
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Key Terms
abdominal cavity
The larger ventral cavity below the diaphragm and above the pelvic
cavity
abdominopelvic
cavity
The larger ventral cavity between the diaphragm and pelvis that
includes the abdominal and pelvic cavity
anatomic position
Standard position for anatomical studies, in which the body is erect
and facing forward, the arms are at the sides with palms forward,
and the feet are parallel
cranial cavity
The dorsal cavity that contains the brain
diaphragm
The muscle that separate the thoracic from the abdominal cavity
frontal (coronal)
plane
Plane of section that separates the body into anterior (front) and
posterior (back) portions
pelvic cavity
The ventral cavity that is below the abdominal cavity
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Key Terms (cont’d)
peritoneum
The large serous membrane that lines the abdominopelvic cavity
and cover the organs with it
sagittal plane
Plane that divides the body into right and left portions
spinal cavity (canal)
Dorsal cavity that contains the spinal cord
thoracic cavity
The ventral cavity above the diaphragm; the chest cavity
transverse (horizontal)
plane
Plane that divides the body into superior (upper) and inferior
(lower) portions
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Supplementary Terms
digit
A finger or toe (adjective, digital)
epigastrium
The epigastric region
fundus
The base or body of a hollow organ; the area of an organ farthest from
its opening
hypochondrium
The hypochondriac region (left or right)
lumen
The central opening within a tube or hollow organ
meatus
A passage or opening
orifice
The opening of a cavity
os
Mouth; any body opening
septum
A wall dividing two cavities
sinus
A cavity, as within a bone
sphincter
A circular muscle that regulates an opening
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Abbreviations
LLQ
Left lower quadrant
LUQ
Left upper quadrant
RLQ
Right lower quadrant
RUQ
Right upper quadrant
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Directional Terms
• Anatomical position
– Beginning reference point
– Body upright
– Facing front
– Arms at side, palms forward
– Feet parallel
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Planes of Section
• Frontal plane
– Coronal plane
– Divides body into anterior, posterior parts
• Sagittal plane
– Divides body into right, left portions
– If plane cuts midline, called midsagittal or medial plane
• Transverse plane
– Divides body into superior, inferior parts
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Planes of Section (cont’d)
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Body Cavities
• Dorsal cavity contains:
– Cranial cavity
– Spinal cavity
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Body Cavities (cont’d)
• Ventral cavity contains:
– Thoracic cavity
– Diaphragm
• Separates thoracic and abdominal cavity
– Abdominopelvic cavity:
• Abdominal cavity
• Pelvic cavity
• Peritoneum
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Side View of Body Cavities
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Abdominal Regions
• Imaginarily divided into 9 regions
• Midline sections:
– Epigastric = above stomach
– Umbilical = umbilicus or navel
– Hypogastric = below the stomach
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Abdominal Regions (cont’d)
• Lateral sections:
– Right and left hypochondriac
• Positioned near ribs, specifically cartilages
– Right and left lumbar
• Positioned near small of back (lumbar region)
– Right and left iliac
• Named for upper bone of hip (ilium)
• Also called inguinal region (referring to groin)
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Nine Regions of Abdomen
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Roots of Regions of Head and Trunk
Root
Meaning
Example
Definition of example
cephal/o
head
megacephaly
abnormal largeness of the head
cervic/o
neck
cervicofacial
pertaining to the neck and face
thorac/o
chest, thorax
thoracotomy
incision (-tomy) into the chest
abdomin/o
abdomen
intra-abdominal
within the abdomen
celi/o
abdomen
celiocentesis
surgical puncture (centesis) of the
abdomen
lapar/o
abdominal wall
laparoscope
instrument (-scope) for viewing the
peritoneal cavity through the abdominal
wall
lumb/o
lumbar region,
lower back
thoracolumbar
pertaining to the chest and lumbar region
periton,
peritone/o
peritoneum
peritoneal
pertaining to the peritoneum
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Roots for Extremities
Root
Meaning
Example
Definition of Example
acro
extremity, end
acrocyanosis
bluish discoloration of the
extremities
brachi/o
arm
antebrachium
forearm
dactyl/o
finger, toe
polydactyly
having more than the normal
number of fingers or toes
ped/o
foot
pedometer
instrument that measures
footsteps
pod/o
foot
podiatric
pertaining to study and
treatment of the foot
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Prefixes for Position and Direction
Prefix
Meaning
Example
Definition of Example
circum-
around
circumoral
around the mouth
peri-
around
periorbital
around the orbit (eye socket)
intra-
in, within
intravascular
within a vessel (vascul/o)
epi-
on, over
epithelial
referring to epithelium, tissue
that covers surfaces
extra-
outside
extrathoracic
outside the thorax
infra-*
below
Infrascapular
Below the scapula (shoulder
blade)
* Also indicates degree.
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Prefixes for Position and Direction
(cont’d)
Prefix
Meaning
Example
Definition of Example
sub-*
below, under
sublingual
under the tongue (lingu/o)
inter-
between
intercostal
between the ribs (cost/o)
juxta-
near, beside
juxtaposition
a location near or beside
another structure
para-
near, beside
parasagittal
near or beside a sagittal plane
retro-
behind,
backward
retrouterine
behind the uterus
supra-
above
suprapatellar
above the patella (kneecap)
* Also indicates degree.
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Pretest
1. In humans, ventral is another term for:
(a) lateral
(b) central
(c) posterior
(d) anterior
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Pretest
1. In humans, ventral is another term for:
(a) lateral
(b) central
(c) posterior
(d) anterior
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Pretest
2. A plane that divides the body into left and right parts is
a:
(a) coronal plane
(b) sagittal plane
(c) transverse plane
(d) frontal plane
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Pretest
2. A plane that divides the body into left and right parts is
a:
(a) coronal plane
(b) sagittal plane
(c) transverse plane
(d) frontal plane
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Pretest
3. The scientific name for the chest cavity is:
(a) cervical cavity
(b) thoracic cavity
(c) dorsal cavity
(d) pelvic cavity
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Pretest
3. The scientific name for the chest cavity is:
(a) cervical cavity
(b) thoracic cavity
(c) dorsal cavity
(d) pelvic cavity
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Pretest
4. The brain and spinal cord are in what cavity?
(a) dorsal cavity
(b) abdominal cavity
(c) thoracic cavity
(d) ventral cavity
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Pretest
4. The brain and spinal cord are in what cavity?
(a) dorsal cavity
(b) abdominal cavity
(c) thoracic cavity
(d) ventral cavity
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Pretest
5. The root cephal/o refers to the:
(a) spine
(b) head
(c) chest
(d) lungs
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Pretest
5. The root cephal/o refers to the:
(a) spine
(b) head
(c) chest
(d) lungs
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Pretest
6. The root brachi/o refers to the:
(a) head
(b) spinal cord
(c) leg
(d) arm
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Pretest
6. The root brachi/o refers to the:
(a) head
(b) spinal cord
(c) leg
(d) arm
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Pretest
7. The prefix peri- means:
(a) under
(b) around
(c) above
(d) within
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Pretest
7. The prefix peri- means:
(a) under
(b) around
(c) above
(d) within
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Pretest
8. The prefix juxta- means:
(a) near
(b) below
(c) away from
(d) medial
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Pretest
8. The prefix juxta- means:
(a) near
(b) below
(c) away from
(d) medial
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