Lesson 8 - Anatomical Terms 1
Student Performance Objectives
1. Describe the anatomical position for a human and for a cat or rat.
2. Define and give an example for each of the following pairs of terms: anterior-posterior,
superior-inferior, ventral-dorsal, proximal-distal, medial-lateral, superficial-deep, cephalad-caudad.
3. Explain why these terms are called relative terms.
A. The Anatomical Position - this is the human body's reference position in which the body is upright, head facing forward, arms at the sides with palms facing forward, and legs slightly apart. All references to the anatomical relationships of parts of the human body, surface and interior, are made with this position of the body in mind.
B. Relative Positions, their common meanings, and examples.
1. Anterior-posterior: front-back. The eyes, nose and mouth are located on the anterior surface of the head. Your buttocks are located on the posterior surface of your pelvic region.
2. Superior-inferior: top-bottom. Your forehead is superior to your eyes. Your eyes are inferior to your forehead. Your diaphragm is superior to your liver. Your liver is inferior to your diaphragm.
3. Ventral-dorsal: side opposite backbone-side possessing the backbone. Your vertebral column is located on the dorsal (or posterior) region of your trunk. Your navel is located on the ventral (or anterior) region of your trunk. For an animal that walks on four legs like a horse or a cat or rat, the ventral or belly surface is inferior (not anterior as in a human); the dorsal surface of a cat is also its superior surface (not posterior, as in a human). This is because the anatomical or natural position for a four-legged animal is down on all its legs.
4. Proximal-distal: nearer a point of attachment-further from a point of attachment. The hand is at the distal end of your arm. Your hand is distal to the wrist. Your wrist is proximal to your hand. The shoulder is at the most proximal end of your arm.
5. Medial-lateral: nearer to the midline - further from the midline. Your nose is medial to your cheeks. Your cheeks are lateral to your nose.
6. Superficial-deep: nearer to the surface - further from the surface. Your subcutaneous fat is deep to the skin. Your skin is superficial to your subcutaneous fat layer.
7. Cephlad-caudad: nearer to the head - further from the head. If you make an incision on a rats belly from its lower pelvic area up toward the thoracic cavity, the cut is proceeding in the cephalad direction. A cut downward from the diaphragm toward the pelvic region is proceeding in a caudad direction.
C. Utilize examples to write a brief essay explaining why these terms are called relative terms.