Directional Terms

Table A.1 summarizes frequently used terms that describe the position of one structure relative to another. Intermediate directions are often indicated by combinations of

Directional Term Pictures

1sagitta = arrow

Anatomical Planes

Figure A.3 Anatomical Planes of Reference.

What is the other name for the particular sagittal plane shown here?

> M ^

(b)

Transverse Plane Kidney Mcgraw

Figure A.4 Views of the Body in the Three Primary Anatomical Planes. (a) Sagittal section of the pelvic region. (b) Frontal section of the thoracic region. (c) Transverse section of the head at the level of the eyes.

Figure A.3 Anatomical Planes of Reference.

What is the other name for the particular sagittal plane shown here?

Figure A.4 Views of the Body in the Three Primary Anatomical Planes. (a) Sagittal section of the pelvic region. (b) Frontal section of the thoracic region. (c) Transverse section of the head at the level of the eyes.

Saladin: Anatomy & I Atlas A General I Text I © The McGraw-Hill

Physiology: The Unity of Orientation to Human Companies, 2003

Form and Function, Third Anatomy Edition

32 Part One Organization of the Body

Table A.1 Directional Terms in Human Anatomy

Term

Ventral

Dorsal

Anterior

Posterior

Superior

Inferior

Medial

Lateral

Proximal

Distal

Superficial

Deep

Meaning

Toward the front* or belly Toward the back or spine Toward the ventral side* Toward the dorsal side* Above Below

Toward the median plane

Away from the median plane

Closer to the point of attachment or origin

Farther from the point of attachment or origin

Closer to the body surface

Farther from the body surface

Examples of Usage

The aorta is ventral to the vertebral column.

The vertebral column is dorsal to the aorta.

The sternum is anterior to the heart.

The esophagus is posterior to the trachea.

The heart is superior to the diaphragm.

The liver is inferior to the diaphragm.

The heart is medial to the lungs.

The eyes are lateral to the nose.

The elbow is proximal to the wrist.

The fingernails are at the distal ends of the fingers.

The skin is superficial to the muscles.

The bones are deep to the muscles.

*In humans only; definition differs for other animals.

these terms. For example, one structure may be described as dorsolateral to another (toward the back and side).

Because of the bipedal, upright stance of humans, some directional terms have different meanings for humans than they do for other animals. Anterior, for example, denotes the region of the body that leads the way in normal locomotion. For a four-legged animal such as a cat, this is the head end of the body; for a human, however, it is the area of the chest and abdomen. Thus, anterior has the same meaning as ventral for a human but not for a cat. Posterior denotes the region of the body that comes last in normal locomotion—the tail end of a cat but the dorsal side (back) of a human. These differences must be kept in mind when dissecting other animals for comparison to human anatomy.

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