Anatomical Terms: Directional Terms (Anatomy)

In this video we will be discussing anatomical
directional terms, or simply anatomical terms. Anatomical terms help us to identify the location
of both internal and external body structures. Most of these terms are used to identify where
something is located on the body relative to another body part. These terms refer to
the locations of human body parts as they occur in the the universal anatomical position.
The anatomical position is an upright standing position with arms at the side, palms facing
forward, and both feet together. When we need describe the location of a body
part as above or below another body part we use the terms superior and inferior. When
a body part is superior, it is considered vertically closer to the top of the head in
the anatomical position. On the other hand, a body part is considered inferior if it is
closer to the bottom of the feet. For example, with the abdomen as the point
of reference, we could say that it is both superior to the pelvis and inferior to the
chest. When we need to describe the location of a
body part as in front of, or behind, another body part we use the terms anterior and posterior
[bring in slide title]. Like other anatomical directional terms, a body part being either
anterior or posterior depends on the point of reference. Anterior is towards the front
of the body while posterior is toward the back of the body. For example, the nose is anterior to the ears,
and using these same points of reference, we can say that the ears are posterior to
the nose. Please note: the terms ventral and dorsal
are used interchangeably with anterior and posterior when referring to both human and
animal body parts. However, the terms anterior and posterior are mainly used for locating
human body parts. If you want to describe the location of something
that is relative to the middle of the body you would use the term medial. To identify
something located medially, you would create a mid-line division of the body. The mid-line
is an imaginary line that goes from top-to-bottom and divides your body into two equal parts
left and right. When you have the mid-line, the body part that is closer to the mid-line
division is medial to the structure farther from the mid-line. The structure that is farther away from the
mid-line is referred to as lateral. Whether you use lateral or medial to describe a structure
largely depends on the site you have to describe. Here are some examples. The bicep muscle in
the upper arm is lateral to the pectoral muscle in the chest. Further, in the anatomical position
we could say that the pinky finger is medial to the thumb. “Proximal” and “distal” are used to
describe the location of points on a limb relative to that limb’s connection to the
torso. The proximal site is the one that is closer
to the limb’s point of attachment, while the distal site is the point that lies further
away from the point of attachment. As an example, the wrist is distal to the
elbow, and the elbow is proximal to the wrist. “Superficial” and “deep” are the last
two directional terms we will cover. Superficial, refers to a location towards
the surface of a body structure or organ. While deep, is concerned with a location that
is towards the center of a body structure or organ. For instance, if we look at a cross section
of the skin, the top skin layer, called the epidermis is superficial to the subcutaneous
layer. The subcutaneous layer is considered deep to the epidermis.