msk

							Clinical Skills
    MSK
                    Objectives
   By the end of the session, the student will have:
     1. Been exposed to some common imaging
      modalities used to evaluate the musculoskeletal
      system
     2. Been exposed to the imaging of some common
      musculoskeletal pathologies
     3. Practiced an approach to description and analysis
      of images of the musculoskeletal system
                                 Plan
   Goal:
       To form an approach to MSK radiology
   Organization:
     Basic anatomy
     Approach to MSK radiology

     Pathology
            Plain films to review
                   Types of bones
   Long bones
       Femur, tibia, humerus, phalanges, vertebrae
   Flat bones
       Skull, pelvis, scapula
   Sesamoid bones
       Patella
Anatomy
       Long bones:
           Diaphysis: shaft
           Epiphysis: ends
           Metaphysis: Region joining
            diaphysis and epiphysis
           Articular cartilage: thin layer
            hyaline cartilage
           Periosteum:
                Fibrous: dense connective
                 tissue
                Osteogenic: Inner layer with
                 elastic fibers, cells, vessels
           Medullary or marrow cavity
                      Types of Joints
   Functional classification:
       Synarthrosis: immovable joint
            Sutures, teeth, epiphysis
       Amphiarthrosis: slightly movable joint
            Distal articulation of tibia and fibula, between
             intervertebral discs and vertebral bodies
       Diarthrosis: freely movable joint
            Aka synovial joints
              Approach to Radiology
   Basic concepts:
       X-rays-produced by bombarding tungsten with an electron
        beam.
       When X-rays hit photographic film:
            a photochemical process takes place in which metallic silver is
             precipitated rendering the film black when developed.
       As the x-rays project through an object (ex. a hand), the
        various parts of an object will absorb part or all of the x-rays
        so that more or less of the x-rays will the photographic film
Radiology concepts
Approach to Radiology
              Air: black
              Fat: dark gray
              Soft tissues: gray
              Bones: white (has Ca++
               which absorbs more than
               soft tissues)
              Metal: Every metal
               absorbs X-rays
               depending on thickness
               and atomic number
            Terms in Radiology
   Radioopaque: more dense
   Radiolucent: more transparent
   Factors affecting appearance:
     Density/Composition
     Thickness

     Summation of all X-ray shadows

     Technical factors: kilovoltage, time of exposure
                   MSK Radiology
   Approach: ABCs
     Alignment
     Bones:
         Density
         Cortical continuity

     Cartilage
     Soft tissues
Alignment
        With most joints, two
         surfaces will be congruent
         (similarly shaped) and should
         line up with one another
        Ball (convex) in cup
         (concave)
        Subluxation: displacement
         causing partial loss of
         continuity of joint surfaces
        Displacement: displacement
         causing complete loss of
         continuity of joint surfaces
Bone
     Abnormal opacity
          Decreased (lucency)
          Lucent line
               Classical sign of fracture
Types of fractures
                 Alignment:
                     Angulated or
                      straight
                 Open vs Closed
                     Open: Skin is
                      open
                     Closed: no
                      opening in skin
Bone
     Focal lucency:
          Bone tumors
               Benign
               Malignant
          Osteomyelitis
          Pt Hx is key



          Multiple myeloma patient with
           several lytic lesions of the ulna.
Osteomyelitis
          Earliest finding: Osteopenia
          Osseous destruction
           followed by pathologic
           fracture
          May spread to adj joint
          Evidence of destruction on
           both sides of the joint is
           strong evidence of septic
           joint
              AP view of a great toe with
               marked osteomyelitis, a septic
               joint and a pathologic fracture
               of the toe.
Bone
     Diffuse lucency
          Osteoporosis
               This patient has diffuse
                osteopenia due to
                osteoporosis, and has
                developed an insufficiency
                fracture in his T6 vertebral
                body.
          Multiple myeloma
Bone
     Increased Opacity
      (Sclerosis)
     bone impaction or rotation
          fracture
     bone production (reactive
      sclerosis)
          fracture --> callus
          tumor --> tumor bone
           formation or periosteal
           reaction
          infection --> periosteal
           reaction
          osteoarthritis --> subchondral
           sclerosis or osteophytosis
Cartilage
        Hyaline articular cartilage
         separates bones in a joint
         space
        Radiographic findings:
            decreased joint space
                 Arthritis
            increased joint space
            Chondrocalcinosis:
                 Deposition of CPPD
                  crystals in hyaline articular
                  cartilage of fibrocartilage
Arthritis
        Osteoarthritis:
            Degenerative alterations
             in a synovial joint. This is
             the most common
             articular affliction there is.
        Findings:
            Osteophytes
            Asymmetric joint space
             narrowing
            DIP, PIP
Arthritis
        Rheumatoid arthritis
            An inflammatory
             arthropathy of unknown
             etiology, characterized by
             synovial inflammation,
             pannus formation and
             erosion formation.
        Findings:
            Erosions
            Symmetric joint space
             narrowing
            MCP, PIP
Chondrocalcinosis
            CPPD (95%)
                calcium pyrophosphate
                 deposition (CPPD)
                 disease
Soft tissue
         swelling:
             localization
         gas
             Penetrating injuries, post
              surgery or infections
         calcification:
             Usually implies some
              tissue damage with
              dystrophic calcification
         mass: hematoma, tumor
          or abscess (MRI)
              Differential Diagnosis
   VINDICATE" for                     Autoimmune
    Musculoskeletal Disease
   Vascular osteonecrosis                rheumatoid arthritis
   Infection                             ankylosing spondylitis
      osteomyelitis
      abscess                         Trauma
   Neoplasm                              fracture
      mets
      myeloma                            dislocation
      benign                          Endocrine / metabolic
   Drugs
                                          Paget's
      steroids --> osteonecrosis
   Inflammatory                          hyperparathyroidism
   Congenital
                                          gout
Normal Anatomy: Shoulder
Normal Anatomy: shoulder
Normal Anatomy: Hand
Normal Anatomy: Hand
Normal Anatomy: Pelvis
Normal Anatomy: Pelvis
Normal Anatomy: Ankle
Normal Anatomy: Ankle
Normal Anatomy: Knee
Normal Anatomy: Knee
C-Spine
       Anterior vertebral line
       Posterior vertebral line
       Posterior border of facets
       Laminar fusion line
       Spinous process line
       Soft tissue: Up to C4 ½ vert
        body
       Beyond C4: 1 vert body
       McGregor line (Hard palate
        to base of skull <4.5mm)
C-Spine