Human Anatomy Chapter 1: Position, Direction, Regions, and Structures

In anatomy, exact terms are used for Position, Direction, Regions, and Structures.

• Anatomical Position: standard body position used to avoid confusion; terminology refers to this POSITION regardless of body position

  Example: stand erect, feet parallel, arms hanging at the sides w/ palms forward

• Directional Terms: explain the location of one body structure in relation to another

  Superior (cranial or cephalic): toward the head or upper part of a structure or the body; above Inferior (caudal): away from the head or toward the lower part of a structure or the body; below

  Anterior (ventral): toward or at the front of the body; in front of posterior (dorsal): toward or at the backside of the body; behind

  Medial: toward or at the midline of the body; on the inner side of lateral: away from the midline of the body; on the outer side of intermediate: between a more medial and a more lateral structure (middle)

  Proximal: close to the origin of the body part or point of attachment to a limb to the body trunk (shoulder to elbow; proximal) distal: farther from the origin of a body part or the point of attachment of a limb to the body trunk (shoulder to wrist; distal)

  Superficial (external): toward or at the body surface (skin superficial to the skeleton) deep (internal): away from the body surface; more internal (lungs deep to the rib cage)

• Body planes and sections: cut along imaginary lines known as planes

• Sagittal section: divides body/organ into left and right parts

• Median/midsagittal section: divides body/organ into EQUAL left and right parts (vertically down the middle)

• Frontal/coronal section: divides body/organ into anterior/posterior parts (vertical hamburger slice in the body)

• Transverse/cross-section: divides body/organ into superior/inferior parts (in half horizon)

Body cavities: protect organs within them

Dorsal: back side of the body

Cranial cavity: holds the brain/protection skull

Spinal cavity: holds the spinal cord/protection

Vertebrae ventral: front side of the body

Thoracic/chest cavity: holds the heart/lungs/others, above (superior to) diaphragm/protection rib cage

Abdominal cavity: holds stomach/liver/others, inferior to the diaphragm (below)/ protection from trunk muscles

Pelvic cavity: inferior to the abdominal cavity, holds reproductive organs, bladder, rectum/ partially protected by bony pelvis

• Abdominopelvic cavity subdivisions: four quads, nine regions