Terminology, Positioning, and Imaging Principles - Chapter 1

TERMINOLOGY, POSITIONING, AND IMAGING PRINCIPLES

CHAPTER 1

PART ONE: TERMINOLOGY AND POSITIONING

GENERAL, SYSTEMIC, AND SKELETAL ANATOMY AND ARTHROLOGY
General Anatomy

  • Anatomy: Study, classification, and description of the structure and organs of the human body.

  • Physiology: Focuses on processes and functions, explaining how body parts operate.

  • Radiographic Study: Primarily emphasizes anatomy over physiology, particularly for imaging purposes.

  • Pronunciation Aid: Phonetic respelling of anatomical and positioning terms is provided throughout to facilitate correct pronunciation in medical radiography.

Structural Organization

  • Multiple levels of structural organization in the human body:

    • Chemical Level: Composed of atoms forming molecules.

    • Cell Level: Basic unit of living tissue, comprising muscle, bone, cartilage, fat, nerve, skin, and blood.

    • Tissue Level: Cohesive groups of similar cells performing specific functions. Four main types:

      1. Epithelial: Covers surfaces of organs and vessels.

      2. Connective: Binds and supports structures.

      3. Muscular: Forms muscles.

      4. Nervous: Comprises nerves and nerve centers.

    • Organ Level: Composed of complex assemblies of tissues performing specific functions (e.g., heart, kidneys).

    • System Level: Groups of organs with similar functions (e.g., urinary system).

    • Organism Level: The entire human body, comprising 10 systems.

SYSTEMIC ANATOMY
BODY SYSTEMS

  • The human body consists of 10 systems:

    1. Skeletal

    2. Circulatory

    3. Digestive

    4. Respiratory

    5. Urinary

    6. Reproductive

    7. Nervous

    8. Muscular

    9. Endocrine

    10. Integumentary

Skeletal System

  • Key for technologists, consists of 206 bones along with associated cartilages and joints.

  • Osteology: Study of bones.

  • Arthrology: Study of joints.

  • Functions:

    1. Protects soft tissues.

    2. Allows movement via muscular interaction.

    3. Produces blood cells.

    4. Stores calcium.

Circulatory System

  • Comprises:

    • Cardiovascular Organs: Heart, blood, blood vessels.

    • Lymphatic System: Lymph nodes, vessels, glands, spleen.

  • Functions:

    1. Distributes oxygen and nutrients to cells.

    2. Removes waste and carbon dioxide.

    3. Transports water, electrolytes, hormones, enzymes.

    4. Protects against disease.

    5. Prevents hemorrhage through clot formation.

    6. Regulates body temperature.

Digestive System

  • Includes the alimentary canal and accessory organs (e.g., salivary glands, liver).

  • Function:

    1. Prepares food for cellular absorption.

    2. Eliminates solid waste.

Respiratory System

  • Comprises two lungs and passageways (e.g., trachea, bronchial tree).

  • Functions:

    1. Supplies oxygen to blood.

    2. Removes carbon dioxide.

    3. Regulates blood's acid-base balance.

Urinary System

  • Composed of kidneys, ureters, bladder, urethra.

  • Functions:

    1. Regulates blood's chemical composition.

    2. Eliminates waste products.

    3. Balances fluids and electrolytes.

    4. Maintains acid-base balance.

Reproductive System

  • Includes organs for producing and transporting germ cells (e.g., testes, ovaries).

  • Function: Reproduction of the organism.

Nervous System

  • Includes the brain, spinal cord, nerves, ganglia, special sense organs (e.g., eyes, ears).

  • Function: Coordinates body activities and transmits electrical impulses.

Muscular System

  • Composed of skeletal, smooth, and cardiac muscle tissues.

  • Functions:

    1. Allows bodily movement.

    2. Maintains posture.

    3. Produces heat.

Endocrine System

  • Comprises all ductless glands (e.g., thyroid, pituitary).

  • Function: Regulates body activities via hormones released into the bloodstream.

Integumentary System

  • Composed of skin and its derivatives (hair, nails).

  • Functions:

    1. Regulates body temperature.

    2. Protects from microbial invasion and damage.

    3. Eliminates waste through perspiration.

    4. Receives stimuli (e.g., temperature, pressure).

    5. Synthesizes vitamins, like vitamin D.

SKELETAL ANATOMY

OSTEOLOGY

  • Consists of 206 bones creating the framework of the body, including cartilages, united by ligaments.

  • Divisions:

    • Axial Skeleton (80 bones): Includes skull, vertebrae, ribs, sternum.

    • Appendicular Skeleton (126 bones): Comprises upper/lower limbs, shoulder, pelvic girdles.

Classification of Bones

  • Long Bones: Have a body and two extremities (e.g., femur).

  • Short Bones: Cuboidal in shape (e.g., carpals).

  • Flat Bones: Composed of two layers of compact bone with marrow in between (e.g., skull).

  • Irregular Bones: Unique shapes (e.g., vertebrae).

DEVELOPMENT OF BONES

  • Ossification: Process where bones form, beginning around the sixth embryonic week and continuing into adulthood.

    • Intramembranous Ossification: Bone replaces membranes, occurring rapidly.

    • Endochondral Ossification: Bone replaces cartilage, slower process.

ARTHROLOGY (Joints)

  • Arthrology: Study of joints, vital for understanding movement.

Classification of Joints

  • Functional Classification:

    1. Synarthrosis: Immovable joints.

    2. Amphiarthrosis: Slightly movable joints.

    3. Diarthrosis: Freely movable joints.

  • Structural Classification:

    1. Fibrous Joints: No joint cavity, bones joined by fibrous tissue.

    2. Cartilaginous Joints: Bones held together by cartilage.

    3. Synovial Joints: Freely movable with joint cavity and fluid.

BODY HABITUS

  • Body Habitus: Refers to the build, physique, and shape of the human body, impacting radiographic positioning.

  • Classifications:

    1. Sthenic: Average physique (50%).

    2. Hyposthenic: Slender (35%).

    3. Hypersthenic: Massive build (5%).

    4. Asthenic: Very slender (10%).

POSITIONING TERMINOLOGY

  • Radiographic Positioning: Refers to the placement of patients for optimal radiographic images.

  • Definitions:

    • Radiograph: Image produced by the action of x-rays on an image receptor.

    • Radiography: The process of producing radiographs.

    • Image Receptor (IR): Device capturing the radiographic image.

    • Central Ray (CR): Center portion of the x-ray beam.

  • Anatomic Position: Standard reference position: upright, arms at sides, palms forward.

BODY PLANES, SECTIONS, AND MOVEMENT TERMS

Common Body Planes

  • Sagittal Plane: Divides the body into right and left.

  • Coronal Plane: Divides body into anterior (front) and posterior (back).

  • Horizontal (Axial) Plane: Divides the body into superior (upper) and inferior (lower) portions.

  • Oblique Plane: Intersects at an angle, not parallel to standard planes.

Relationship Terms

  • Medial/Lateral: Towards/away from the median plane.

  • Proximal/Distal: Near/Far from the trunk of the body.

  • Cephalad/Caudad: Toward/Away from the head.

  • Ipsilateral/Contralateral: Same side/Opposite side.

Terms Related to Movement

  • Flexion/Extension: Decreasing/increasing the angle between joint parts.

  • Dorsiflexion/Plantar Flexion: Movements concerning the foot/hand; upward/downward.

  • Eversion/Inversion: Outward/inward movements of the foot.

  • Abduction/Adduction: Away from/towards the body.

  • Supination/Pronation: Rotating the hand into/away from the anatomic position.

  • Elevation/Depression: Moving a body part superiorly/inferiorly.

  • Circumduction: Circular movement combining flexion, extension, abduction, and adduction.

  • Rotation/Tilt: Turning a part about its axis/slanting in reference to the long axis.

SUMMARY OF POSITIONING TERMS

  • Projections: Describe the path of the CR (e.g., PA, AP, axial).

  • General Body Positions: Position of the patient (e.g., supine, prone).

  • Specific Body Positions: Described by the surface closest to the IR (e.g., lateral, oblique).