| Directional terms describe the positions of
structures relative to other structures or locations in
the body.
Superior or cranial
toward the head end of the body; upper (example, the
hand is part of the superior extremity).
Inferior or caudal
away from the head; lower (example, the foot is part of
the inferior extremity).
Anterior or ventral
front (example, the kneecap is located on the anterior
side of the leg).
Posterior or dorsal
back (example, the shoulder blades are located on the
posterior side of the body).
Medial
toward the midline of the body (example, the middle toe
is located at the medial side of the foot).
Lateral
away from the midline of the body (example, the little
toe is located at the lateral side of the foot).
Proximal
toward or nearest the trunk or the point of origin of a
part (example, the proximal end of the femur joins with
the pelvic bone).
Distal
away from or farthest from the trunk or the point or
origin of a part (example, the hand is located at the
distal end of the forearm). |
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Medical professionals often refer to sections of the
body in terms of anatomical planes (flat surfaces).
These planes are imaginary lines - vertical or
horizontal - drawn through an upright body. The terms
are used to describe a specific body part.
Coronal Plane
(Frontal Plane)
A vertical plane running from side to side;
divides the body or any of its parts into
anterior and posterior portions.
Sagittal
Plane (Lateral Plane)
A vertical plane running from front to back;
divides the body or any of its parts into
right and left sides.
Axial
Plane (Transverse Plane)
A horizontal plane; divides the body or any
of its parts into upper and lower parts.
Median
plane
Sagittal plane through the midline of the
body; divides the body or any of its parts
into right and left halves.
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The cavities, or spaces, of the body contain
the internal organs, or viscera. The two
main cavities are called the ventral and
dorsal cavities. The ventral is the larger
cavity and is subdivided into two parts
(thoracic and abdominopelvic cavities) by
the diaphragm, a dome-shaped respiratory
muscle.
Thoracic
cavity
The upper ventral, thoracic, or chest cavity
contains the heart, lungs, trachea,
esophagus, large blood vessels, and nerves.
The thoracic cavity is bound laterally by
the ribs (covered by costal pleura) and the
diaphragm caudally (covered by diaphragmatic
pleura). |
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Abdominal and pelvic
cavity
The lower part of the ventral (abdominopelvic) cavity
can be further divided into two portions: abdominal
portion and pelvic portion. The abdominal cavity
contains most of the gastrointestinal tract as well as
the kidneys and adrenal glands. The abdominal cavity is
bound cranially by the diaphragm, laterally by the body
wall, and caudally by the pelvic cavity. The pelvic
cavity contains most of the urogenital system as well as
the rectum. The pelvic cavity is bounded cranially by
the abdominal cavity, dorsally by the sacrum, and
laterally by the pelvis.
Dorsal cavity
The smaller of the two main cavities is called the
dorsal cavity. As its name implies, it contains organs
lying more posterior in the body. The dorsal cavity,
again, can be divided into two portions. The upper
portion, or the cranial cavity, houses the brain, and
the lower portion, or vertebral canal houses the spinal
cord. |
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