Chapter 1 Notes: Terminology, Positioning, and Imaging Principles

Levels of Human Structural Organization

  • Molecule
  • Atoms
  • Cell
  • Tissue
  • Organ
  • System
  • Organism
  • (10 systems)

Skeletal System

  • Bones
  • Total adult skeleton: 206 separate bones
  • Osteology
  • Arthrology

Digestive and Excretory/Respiratory Systems (Overview)

  • Digestive System: Functions — Absorption and Elimination
  • Respiratory System: Provides oxygen; Eliminates carbon dioxide
  • Urinary System: Regulates blood; Eliminates waste products

Reproductive System

  • Reproduces organisms
  • Male and Female components depicted

Axial and Appendicular Skeletons

  • Axial skeleton: 80 bones
    • Central axis of body: skull, vertebral column, ribs, sternum
  • Appendicular skeleton: 126 bones
    • Limbs; Shoulder and pelvic girdles

Bone Types and Anatomy (Internal and External Features)

  • Short and Flat Bones: examples include carpal and tarsal bones; calvarium, sternum, ribs, scapulae
  • Long Bones: limbs; contain compact bone on exterior and spongy bone interior; periosteum surrounding
  • Irregular Bones: vertebrae, facial bones, pelvic bones
  • Classification summary: Short/Flat/Long/Irregular with approximate locations and examples

Bone Development (Growth and Maturation)

  • Primary center: Diaphysis (body)
  • Secondary centers: Metaphysis and Epiphyseal plate
  • Epiphyses development and growth at epiphyseal plates

Joints (Arthrology): Structural vs Functional Classification

  • Structural (tissue-based):
    • Fibrous
    • Cartilaginous
    • Synovial
  • Functional (movement-based):
    • Synarthrodial (immovable)
    • Amphiarthrodial (slightly movable)
    • Diarthrodial (freely movable)

Fibrous Joints (3 Types)

  • Syndesmosis — Amphiarthrodial (slightly movable)
    • Example: distal tibiofibular joint
  • Suture — Synarthrodial (immovable)
    • Example: skull sutures; sutural ligament; roots of teeth
  • Gomphosis — Amphiarthrodial (limited movement)

Cartilaginous Joints (2 Types)

  • Symphyses — Amphiarthrodial (slightly movable)
    • Example: symphysis pubis
  • Synchondroses — Synarthrodial (immovable)
    • Example: epiphyseal cartilage in developing long bones

Synovial Joints (7 Types; generally freely movable)

  • Plane (gliding)
  • Ginglymus (hinge)
  • Trochoid (pivot)
  • Ellipsoid (condyloid)
  • Sellar (saddle)
  • Spheroidal (ball and socket)
  • Bicondylar
  • Common features: joint cavity with synovial fluid, fibrous capsule, accessory ligaments, hyaline articular cartilage

Synovial Joints Movement Types (Examples)

  • Plane (gliding): e.g., Intermetacarpal, Intercarpal
  • Ginglymus (hinge): e.g., Interphalangeal joints (fingers), Elbow joint
  • Trochoid (pivot): e.g., Proximal and distal radioulnar joints; C1-C2 joint
  • Ellipsoid (condyloid): e.g., Wrist joint; Metacarpophalangeal joints (1st–5th)
  • Sellar (saddle): opposing surfaces resemble saddle shape
  • Spheroidal (ball and socket): e.g., Shoulder, Hip
  • Bicondylar: e.g., Knee, temporomandibular region (illustrative)

Quick Quiz Me (Joint Types)

  • Which of the following joints is classified as trochoidal? ◦ Wrist joint ◦ Metacarpophalangeal ◦ Distal radioulnar ◦ Shoulder
  • Which of the following joints is classified as ellipsoidal? ◦ Wrist ◦ Interphalangeal ◦ Ankle ◦ Hip
  • Which of the following joints is classified as bicondylar? ◦ Metacarpophalangeal ◦ First carpometacarpal joint ◦ Proximal radioulnar joint ◦ Knee

Positioning and Terminology (Intro)

  • COPYRIGHT notes indicate standardization; terms used throughout imaging
  • Anatomic Position defined as reference stance for imaging and descriptions

General Terms: Radiography, Radiograph, and Procedures

  • Radiography: the imaging modality; Radiograph is the image produced; Radiographic procedure is the examination
  • Distinguish radiograph from x-ray film (terminology nuance)

Anatomic Position, Planes, and Planes of Skull

  • Anatomic Position: standard reference posture for body orientation
  • Body Planes:
    • Sagittal (midsagittal/median)
    • Coronal (frontal/midcoronal)
    • Horizontal (axial)
    • Oblique planes as needed
  • Planes of the skull include base plane and occlusal plane

Body Surfaces and Orientation

  • Anterior vs Posterior; Ventral vs Dorsal terminology
  • Dorsum and Plantar surfaces defined for hands and feet respectively
  • Midsagittal plane as reference orientation

Central Ray and Projections

  • Central Ray (CR) terminology: PA vs AP projections; CR orientation determines projection type
  • AP and PA Oblique Projections examples
  • Describe oblique projection labeling and positioning

Projections and Positioning Terms

  • Lateral projections: Lateromedial; Mediolateral
  • General body positions and variations in radiography
  • Oblique positions are described as parts of body closest to IR
  • Decubitus positions: Dorsal and Ventral decubitus
  • Axial (superoinferior) projections and AP axial (semiaxial) projections
  • Tangential projections and other specialized views
  • Identify and name various oblique and tangential projections

Projections Practice and Identification

  • Which projection is this? (practice questions on views)
  • Name these projections for different body parts
  • Unique or special projections notes

Relationship Terms (Anatomical Positioning)

  • Medial vs. Lateral
  • Proximal vs. Distal
  • Proximal and distal comparisons along limbs
  • Proximal-lateral relationships on limbs and abdomen

Additional Relationship Terms

  • Superficial vs. Deep
  • Skin (superficial) vs. deeper structures (e.g., humerus)

Movement Terms (Kinesiology)

  • Flexion vs. Extension
  • Hyperextension vs. Flexion (neutral extension between)
  • Hyperextension or dorsiflexion (acute flexion)
  • Radial vs. Ulnar deviation
  • Dorsiflexion vs. Plantar flexion
  • Medial vs. Lateral rotation; Forearm orientation changes
  • Abduction vs. Adduction
  • Supination vs. Pronation
  • Protraction vs. Retraction
  • Elevation vs. Depression
  • Circumduction movements
  • Rotation vs. Tilt

Terminology Review (Key Review Questions)

  • Identify Position/Projection questions
  • Identify Projection/Position questions

Positioning Rules and Principles

  • Importance of lateral and AP views in X-ray
  • Minimum of two projections – 90 degrees apart (orthogonal)
    • Reasons: overlapping structures, lesion localization, fracture alignment
  • Minimum of three projections when joints are in prime interest
    • AP/PA, Lateral, Oblique
  • Long Bones typically require two projections
  • Exceptions to positioning rules:
    • Postreduction upper and lower limbs
    • Pelvis study projection if hip injury is not suspected
    • Abdomen (KUB)

Quizzes and Practice Items

  • Hand: 1, 2, or 3 projections?
  • Forearm: 1, 2, or 3 projections?
  • Femur: 1, 2, or 3 projections?
  • Knee: 1, 2, or 3 projections?
  • Humerus: 1, 2, or 3 projections?

Placing Radiographs for Viewing (Viewer Orientation)

  • Patient facing the viewer; patient’s right to the viewer’s left
  • Lateral projections; Decubitus projections

Viewing Radiographs (Limbs and Chest)

  • Limbs: Anatomic position; Hands and feet: digits up
  • PA chest (L appears reversed) vs AP chest (L appears right-side-up) differences
  • Left lateral decubitus chest; Left lateral chest orientation

Essential IR Markers and Procedure Markers

  • Anatomic side markers must be present on radiographs
  • Example Marker usage and sample procedure markers (LEFT, COMPARISON, SUPINE, …)

Positioning Rules and Principles (Summary)

  • Minimum two projections at 90-degree orthogonality; justification provided above
  • When joints are of prime interest, three projections recommended
  • Long bones usually require two projections
  • Exceptions are scenario-dependent (postreduction, pelvic study with hip injury suspected, abdomen studies)

Viewing and Labeling Guidelines

  • Proper labeling (R marker, left/right) and markers to ensure correct interpretation
  • Viewing orientation guidelines for limbs (hands/feet same as anatomical position) and chest radiographs

Notation and Acknowledgments

  • Referenced imaging principles from standard radiology texts; ensure alignment with institutional protocols