Anatomical Positions of the Human Body

Introduction into Anatomy and Physiology briefly explaining standard terminology regarding positions of the body in reference to structures.

When studying anatomy and physiology it is necessary to use standard, uniform terminology. Uniformity in terms of anatomy makes it possible for everyone to know exactly what you are referring to when speaking of the systems of reference. There are four reference in the body which cover direction, planes, cavities and structural units.

In referring to these systems of reference the body is erect, facing forward with the hands at the sides and palms facing forward.

All referring descriptions in anatomy assume the body to be in this position. It is standard in the use of terms and direction.

Terms of Direction:

*Superior means above.
*Inferior means below.
*The head is superior to the neck. The neck is inferior to the head.
*Anterior or ventral means towards the front or belly side. (Think of an antler on a deer.)
*Posterior or dorsal means toward the back. (Think of a dorsal fin on a shark.)
*Cranial or cephalad means toward the head.
*Medial is mid-line and lateral is side.
*Proximal means the nearest point of attachment while distal means away from the point of attachment.
The elbow is proximal to the wrist or the knee is proximal to the ankle. With distal it's reverse; the wrist is distal to the elbow and the ankle is distal to the knee.

Planes:

Planes are imaginary, flat geometric surfaces which pass through the body. It is especially helpful when referencing the body as a whole or an internal organ.

*The midsagittal plane divides the body at midline into equal left and right halves.
*The sagittal plane runs parallel of the midsagittal plane and divides the body or organ into unequal left and right portions.
*The horizontal or transverse plane divides the body into superior and inferior (upper and lower) portions.
*The frontal or coronal plane divides the anterior and posterior (front and back) portions at right angles to the sagittal plane. It can refer to four quadrants; front left, front right, back left and back right.

Cavities:

*The body contains two major cavities; the dorsal and ventral cavities. It also contains several lesser cavities that house the organs of the body.
*The dorsal cavity is subdivided into the cranial and spinal cavities. The cranial cavity houses the brain and the spinal cavity houses the spinal cord.
*The ventral cavity is subdivided into the thoracic cavity and the abdominopelvic cavity.
*The thoracic cavity contains the heart which is housed in the pericardial cavity and the lungs which are housed in the pleural cavity.
*The abdominopelvic cavity contains the remaining major organs of the body; stomach, spleen, pancreas, ovaries, intestines, liver, etc.

Knowledge of the anatomical positions and reference points of the body is fundamental in the study of any medical field. Many of these terms will become part of your daily vocabulary.

STRUCTURAL UNITS:

*All living matter is made up of cells. Cells are the smallest units of life and the basic building blocks composing the human body.
*Cells organize to make tissues.
*Tissues organize to make organs.
*Organs make up the major systems of the body.

The systems of the body include; Integumentary, Skeletal, Muscular, Nervous, Endocrine, Cardiovascular, Lymphatic, Respiratory, Digestive, Urinary and Reproductive. These systems will be studied in subsequent articles.

RESOURCES:

http://en.wikipedia.org/wiki/Anatomical_terms_of_location WIKIPEDIA

http://training.seer.cancer.gov/module_anatomy/unit1_3_terminology.html TRAINING SEER

http://www.becomehealthynow.com/article/anatom/704/ BECOME HEALTHY NOW

MATCHING TERMS:

___Superior 1. Lower or below

___Anterior 2. Toward the heart

___Horizontal 3. Near the midline of the body

___Posterior 4. Divides body into superior and inferior

___Proximal 5. Closest to point of attachment

___Inferior 6. Upper or above

___Distal 7. Toward the back

___Lateral 8. Toward the front

___Medial 9. Furtherest from point of attachment

___Midsagittal 10. Toward the side