Ch.1 - Radiology Principles

• The 10 body systems are: integumentary, muscular, skeletal, nervous, respiratory, circulatory, digestive, urinary, endocrine, and reproductive.
• The skeletal system is made up of 206 bones. 80 bones are axial and 126 appendicular.
• The axial skeleton is made up of the central axis which is:

  Skull (Cranial and Facial bones)

  Hyoid

  Auditory ossicles (M,I,S)

  Vertebrae (C,T,L,S,C)

  Thorax (Sternum and Ribs)

  
  
• The appendicular skeleton is made up of:

  Shoulder girdles (Clavicle and Scapula)

  Upper limbs

  Pelvic girdles (Hip bones)

  Lower limbs
• The digestive system focuses on the absorption of nutrients and elimination of food afterward.
• Sesamoid bones are small, oval-shaped bone found in the tendons mostly near joints.

  
• There are 4 bone classifications:

  Long Bones

  Short Bones

  Flat Bones

  Irregular Bones
• Two types of bone formation:

  Intramembranous Ossification - When bone replaces membranes

  Endochondral ossification -When bone replaces cartilage
• Centers of Ossification:

  
• The primary center of ossification is the diaphysis (the body of a bone)
• The secondary center of ossification is the Epiphysis (near the ends of long bone)
• The epiphyseal plates are found between the diaphysis and each epiphysis until skeletal growth is complete.
• The two classifications of joints are Structural and Functional.
• The three structural classifications:

  • Fibrous: Held together by fibrous tissue
  • Cartilaginous: made of cartilage.
  • Synovial: Synovial fluid in joint capsule
• The 3 Functional classifications of joints:

  • Synarthrodial: Immovable
  • Amphiarthrodial: Limited movement
  • Diarthrodial: Freely movable
• The 3 types of Fibrous joints

  • Syndesmosis: (ex. Interosseous ligament)
  • Suture (ex. Skull sutures)
  • Gomphosis (ex. Roots of teeth)
• The 2 types of Cartilaginous joints:

  • Symphyses (ex. Intervertebral joint and Symphysis pubis)
  • Synchondroses (ex. Epiphaseal plates)
• Synovial joint movement types (least to : greatest movement):

  • Plane (gliding)
  • Ginglymus (hinge)
  • Trochoid (pivot)
  • Ellipsoid (condyloid)
  • Sellar (saddle)
  • Spheroidal (ball and socket)
  • Bicondylar
• Plane (gliding): Gliding movement. Ex. Inter-carpal
• Ginglymus (hinge): Flexion and extension only. Ex. Elbow joint
• Trochoid (pivot): Rotational movement around one axis. Ex. C1-2 joint
• Ellipsoid (condyloid ): 4 directional movements. Ex. Wrist joint
• Sellar (saddle):Allows flexion, extension, abduction, adduction, and circumduction. ex. carpometacarpal joint (thumb)
• Spheroidal (ball and socket): Greatest motion freedom. ex. Hip and shoulder joints
• Bicondylar: Moves in Single direction and has limited rotation. ex. TMJ and knee
• Film Screen

  A cassette with film
• Computed radiography (CR)

  A cassette with imaging plate
• Digital radiography (DR):

  No cassette used
• The minimum SID for most skeletal radiographs

  40”
• Increased SID reduces entrance or skin dose
• The standard SID for chest radiographs

  72” to reduce heart magnification
• The 4 body planes:

  • Sagittal

  • Coronal

  • Oblique

  • Horizontal
• ALARA stands for

  As Low As Reasonably Achievable
• The cardinal rules of radiation protection are:

  • Time
  • Distance
  • Shielding
• The types of collimators:

  • Manual type
  • Positive-beam limitation (PBL)
• The 10 day rule and LMP rule are both to protect pregnancies.
• There should be a minimum of 3 projections ( AP/PA, Lateral, and Oblique ) when joints are in prime interest area.

  
• There should always be a minimum of two projections (90 degrees from each other)

  
• Long bones require 2 projections.
• The knee, foot, and ankle require 3 projections minimum.