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Intro2MSRadiology
lecture 27 moore
Question | Answer |
---|---|
systematic approach to reading XRs | bone: alignment, periosteum shouldn't be seen, cortex & cancellous bone // joint: alignment and joint space // soft tissue: edema or effusions |
incomplete fractures | don't extend from cortex to cortex. more common in kids b/c their bones are more elastic. may also be pseudofx in osteomalacia |
open fx | hematoma around the fx communicates with the oustide world. even if bone doesn't protrude out of the skin, if there is gas tracking down the space within, it's still open |
Bayonet apposition | aka overriding or overlapping fx |
signs of fx | cortical disruption, STS, lipo- or hemoarthrosis (will be seen as a straight air-fluid level on lateral & supine view of the joint or fat pad visibility/displacement) |
Colles fx | fx of the distal radius with dorsal displacement |
anterior shoulder dislocation | humeral head is dislocated medially and inferiorly (makes up ~ 95% of all shoulder dislocations) |
posterior shoulder dislocation | only makes up 5-10% of dislocations, humeral head goes straight back and the arm is stuck in internal rotation |
elbow fat pad displacement in an adult = | occult radial head fx until proven otherwise |
burst fx | posterior vertebral body height loss can result in retropulsion of bony fragments into the spinal canal, risking cord injury |
vertebral compression fx | loss of both anterior and posterior vertebral height, due an axial load on the spine |
characteristics of DJD | joint space narrowing & irregularity, sublaxation, osteophyte formation @ joint margin, sclerosis, subchondral cysts, loose bodies and joint effusion |
the most likely places DJD affects the hands | DIP and MCP joints |
characteristics of RA | joint space narrowing, subluxations, marginal erosions, periarticular osteopenia, ankylosis, relative lack of sclerosis or osteophyte production |
1st place that erosions from RA occurs | 5th metatarsal head is usually first. hyperemia from inflammation causes dec Ca2+ for bone formation and results in periarticular osteopenia |
hallmark of psoriatic arthritis | dramatic joint space erosions result in pencil-in-cup deformity of the interphalangeal joints |
septic arthritis | effusions, early joint space widening then narrowing when cartilage is destroyed, periarticular osteopenia, loss of subchondral bone plate & loss of bone when osteomyelitis develops |
XR appearance of bony tumors | most are not primary but due to mets or MM. lytic lesions show inc lucency and faint cortical margins (ex. mets love pedicles of vertebrae, they disappear from view on XR) |
sclerotic bony lesions | lesions are more dense/white, usually to due mets from breast or prostate |
characteristic XR of MM pt | punched-out or lytic lesions of bones especially the cranium |
osteosarcomas | starts in the diametaphysis of long bones, usually cause cortical destruction with visible soft tissue mass |
sunburst appearance | periosteal reaction to rapidly growing tumor at the cortex. tumor lifts the periosteum up and it tries to regrow a cortex, but if it's too fast you get parallel or perpendicular layers |