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161 Cards in this Set
- Front
- Back
What level should be seen on every C-spine film?
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C7
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Name the five cervical spine lines:
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Prevertebral soft tissue line
Anterior vertebral body line Posterior vertebral body line spinolaminal line Spinous process line |
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Which lines contain the spinal cord?
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The posterior vertebral body line and the spinolaminal line
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How far should the anterior arch of C2 be from the dens in adults?
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No more than 2.5mm
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How far should the anterior arch of C2 be from the dens in kids?
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No more than 5 mm
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What is a Jefferson fracture?
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-Splitting of the ring of C1 with widening of the lateral masses
-A bony ring will break in at least two places |
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What causes a Jefferson fracture?
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Blow to the top of the head, like when a heavy object falls on the apex of the skull
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How do you diagnose a Jefferson fracture on plain films?
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The lateral masses of C1 must extend beyond the margins of the C2 body
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How do you diagnose rotary fixation of the atlantoaxial joint?
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-Get open mouth odontoid views with neutral, left, and right rotated views.
-With normal leftward rotation the left space widens and the right space narrows. The opposite happens with rightward rotation -With rotary fixation, one of the spaces is wider than the other and stays wider even with rotation of the neck. |
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When is rotary fixation a serious problem?
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-When there is more than 2.5 mm between the dens and the anterior arch of C1---this means that there is disruption of the transverse ligaments at C1-C2
-Otherwise, rotary fixation is an innocuous malady fixed with soft cervical collar, gentle traction, or both. |
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What causes rotary fixation?
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It’s usually spontaneous, or after very mild trauma, such as sleeping in a weird position
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What is a clay-shoveler’s fracture?
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-Avulsion fracture of the C6-C7 spinous processes
-Relatively inocuous |
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What is a hangman’s fracture?
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Fracture of the posterior elements of C2 and, usually, displacement of the C2 body anterior to C3
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What causes a hangman’s fracture?
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Hyperextension and distraction (like hitting your head against a dashboard)
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How serious is a hangman’s fracture?
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-It is serious, very unstable
-The patients often do okay if immobilized because the fractured posterior elements of C2 allow for decompression of the cord |
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What is a flexion-teardrop fracture?
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Disruption of the posterior ligaments with anterior compression of a vertebral body
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How serious is a flexion-teardrop fracture?
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Very serious, the cord is usually compressed by posterior displacement of the vertebral body into the canal
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How do unilateral locked facets happen?
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Severe flexion with some rotation present
Bilateral locked facets can happen too. |
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Which ligaments are ruptured with locked facets?
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The apophyseal ligaments
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Describe a seatbelt injury to the spine
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Caused by hyperflexion at the waist
Causes anterior compression of vertebral bodies and disruption of the posterior elements and ligaments |
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Which vertebral bodies are usually involved in a seatbelt injury?
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T12, L1, or L2
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What is a Chance fracture?
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Seatbelt fracture with fracture of the spinous processes
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What is spondylolysis?
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Break or defect in the pars interarticularis portion of the lamina
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What is the pars interarticularis?
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The portion of the lamina that lies between the facets
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What views show the Scottie dog?
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Oblique views
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What forms the Scottie dog’s nose?
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The transverse process
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What forms the Scottie dog’s eye?
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The pedicle
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What forms the Scottie dog’s front leg?
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Inferior articular facet
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What forms the Scottie dog’s ear?
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The superior articular facet?
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What forms the Scottie dog’s neck?
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The pars interarticularis
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What does the Scottie dog look like if there is a pars defect?
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The dog will have a collar
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What causes spondylolysis?
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-Can be congenital and/or posttraumatic (it’s controversial)
-Some people think it’s from falling on your butt multiple times when learning how to walk |
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What is the significance of spondylolysis?
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-Most think that it is incidental, asymptomatic in most
-It’s good to know if it’s there. Some have symptoms that mimic disk disease symptoms. |
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What is spondylolisthesis?
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-Happens if spondylolysis is bilateral, and the vertebral body slips anteriorly
-Can be asymptomatic, but can cause neuroforaminal stenosis and impinge of the nerve roots in the central spinal canal |
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What are the different grades of spondylolisthesis?
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-Grade I means that there’s less than 25% offset (as measured by the inferior vertebral body width)
-Grade II means that there’s between 25 and 50% offset -Grade III means that there’s between 50 and 75% offset -Grade IV means that there’s greater than 75% offset |
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How can you tell the age of a compression fracture on plain films?
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You can’t!
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What is Kummel’s disease?
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Neurological deficits caused by incremental collapses of a compression fracture over time
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When does Kummel’s disease happen?
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One to two weeks after an acute compression fracture, if it’s left untreated.
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How should you dictate compression deformities on plain films?
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-They are of indeterminate age, correlate clinically with physical exam and history of back pain.
-If no pain is present, it’s an old compression fracture |
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How do you treat compression fractures?
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A back brace should be worn until they are pain-free
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Should a CT or MRI be done for compression fractures?
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No, they won’t change management
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What is a Bennett fracture?
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Fracture at the base of the thumb into the carpometacarpal joint
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How is a Bennett fracture managed?
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Surgically, with internal fixation (usually).
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Why is a Bennett fracture managed with internal fixation?
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-Because of the strong thumb adductors that insert at the base of the thumb. It is almost impossible to maintain normal alignment of the metacarpal because they will keep sliding off the carpals.
-You have to be careful in checking alignment in these pts on follow-up. |
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What is a pseudo-Bennett fracture?
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A fracture of the base of the thumb that does not extend into the carpometacarpal joint.
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What is a Rolando fracture?
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A comminuted fracture at the base of the thumb that extends into the joint
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What causes mallet finger (baseball finger)?
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Avulsion of the extensor digitorum from the base of the distal phalanx causes flexion deformity.
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What is the volar plate?
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A dense fibrocartilage band that covers the volar side of the interphalangeal and metacarpophalangeal joints
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What is a volar plate fracture and why is it important?
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An avulsion of the volar plate can cause it to get interposed in the adjacent joint, needing surgical removal.
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What is a “gamekeeper’s thumb”?
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Avulsion of the ulnar aspect of the first metacarpophalangeal joint
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What is the treatment of a “gamekeeper’s thumb”?
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Surgical pinning
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Why do gamekeeper's thumb injuries need surgery?
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If the ulnar collateral ligament is torn, normal function of the thumb is impaired
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What causes gamekeeper’s thumb?
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Falling on a ski pole, when the pole jams into the webbing between the thumb and first finger
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What can cause lunate/perilunate dislocation?
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Fall on an outstretched hand
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Which views best show lunate/perilunate dislocation?
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Lateral
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What is the normal configuration of the capitate, lunate, and distal radius?
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The capitate is seated in the cup-shaped lunate, which is seated in the cup shaped distal radius?
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What is the configuration in lunate/perilunate dislocation?
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-The capitate and all of its surrounding bones are displaced dorsally to the lunate (perilunate dislocation)
-The displaced capitate can push the lunate volarly off the distal radius (lunate dislocation) |
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What can happen if lunate/perilunate dislocation isn’t fixed?
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Permanent median nerve impairment (it can get impinged by the lunate)
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How can you see a lunate/perilunate dislocation on AP view?
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By noting a triangular or pie-shaped lunate (it’s usually rhomboid shaped with upper and lower borders parallel)
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Which fractures are assciated with lunate/perilunate dislocation?
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-A transscaphoid fracture
-Capitate, radial styloid, triquetrum also fracture frequently with this injury. |
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Which view is needed to see the hook of the hamate?
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-Carpal tunnel view, with the fingers pulled backwards and the beam 45o to the palm of the hand
-CT is needed if you can’t see the hook of the hamate on a carpal tunnel view |
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What causes fractures of the hook of the hamate?
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-Fall on outstretched hand
-Professional baseball hitters, tennis players, and golfers can get it too when they overswing. |
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What causes rotary subluxation of the navicular?
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Fall on outstretched hand
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How can you diagnose rotary subluxation of the navicular?
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-There is a wide space between the scaphoid (navicular) and the lunate on AP view
-“Terry Thomas” sign after a famous gap-toothed British actor. |
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What is injured in rotary subluxation of the navicular?
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The scapholunate ligament
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Why are scaphoid/navicular fractures important?
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Because of the high rate of avascular necrosis related to these fractures
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How are scaphoid/navicular fractures managed?
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-If there’s pain over the anatomic snuffbox they either get an immediate MRI or they’re casted and re-examined in a week
-A negative x-ray does not rule out a scaphoid fracture |
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Which part of the scaphoid undergoes AVN?
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The proximal portion
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Why does the proximal part of the scaphoid undergoes AVN?
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Because the blood supply begins distally and runs proximally
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Why would a fracture show up better in a week?
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Diffuse osteopenia and hyperemia around the fracture site
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How do you diagnose AVN of the scaphoid?
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Noting increased density in the proximal portion of the scaphoid compared to the rest of the carpal bones
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Which other carpal bone is prone to AVN?
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The lunate (Kienbock malacia)
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What is Kienbock malacia?
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AVN of the lunate?
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What causes Kienbock malacia?
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Trauma, but can be spontaneous
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How do you diagnose Kienbock malacia?
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Noting the increased density of the lunate, which may or may not go on to collapse and fragmentation
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How is Kienbock malacia treated?
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-Surgical bone grafting
-Occassionally needs removal with carpal row fixation |
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What is associated with increased risk of Kienbock malacia?
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Negative ulnar variance
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What is negative ulnar variance associated with?
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Kienbock malacia
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What does negative ulnar variance mean?
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That the ulna is shorter than the radius
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What does positive ulnar variance mean?
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That the ulna is longer than the radius
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What is positive ulnar variance associated with?
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Triangular fibrocartilage tears
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Which view shows avulsion fracture of the triquetrum best?
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The lateral view
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What is a Colles fracture?
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A distal wrist fracture that angulated dorsally
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What is a Smith fracture?
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A distal wrist fracture that is angulated volarly
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What is plastic bowing deformity?
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When a bone bends instead of breaking
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Why is plastic bowing a problem?
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Because it can result in reduced supination and pronation
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How is plastic bowing treated?
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By breaking the bone and resetting it
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What is a Monteggia fracture?
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Ulnar fracture with dislocation of the radial head
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Why is a Monteggia fracture important?
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-You need to catch the radial head dislocation or else it can undergo avascular necrosis if not treated
-So whenever the forearm is fractured, you need to get elbow films too |
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What is a Galeazzi fracture?
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-Fracture of the radius with dislocation of the distal ulna
-Less common than a monteggia |
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What does a displaced posterior fat pad indicate in the setting of trauma?
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What does a displaced posterior fat pad indicate?
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Where's the fracture if you seen elbow fat pads?
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Adult:
It’s probably a fx’d radial head Chidren: It’s probably a supracondylar fx. |
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Do you absolutely need to find the elbow fracture if you see fat pads?
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Not really, it’s going to be treated the same as long as there is no obvious deformity or loose body
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What other things can cause a posterior fat pad?
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Infecion
Arthritide Anything causing an elbow effusion |
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What is the sail sign?
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Displaced anterior fat pad looks like a spinnaker sail
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Which is the most common type of shoulder dislocation?
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Anterior
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What causes anterior shoulder dislocation?
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When the shoulder is forcibly externally rotated and abducted
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What does an anterior shoulder dislocation look like on x-ray?
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The humeral head is inferior and medial to the glenoid
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What is a Hill-Sachs deformity?
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Indentation on the posterosuperior portion of the humeral head
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What causes the Hill-Sachs deformity?
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When the humeral head impacts on the inferior lip of the glenoid
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What does it mean if a Hill-Sachs deformity is present?
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The pt is more likely to re-dislocate
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What is a Bankart deformity?
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A bony irregularity or fragment off the inferior glenoid
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What is the crescent sign?
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The normal crescent of bone where the humeral head overlaps the glenoid
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What does a posterior dislocation look like?
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-It may look normal on AP
-The crescent of bony overlap may be absent and a small space is seen between the humeral head and the glenoid |
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How can you unequivocally diagnose a posterior shoulder dislocation?
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Get a transscapular view
The beam is angled along the blade of the scapula |
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What can look just like a shoulder dislocation?
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A traumatic hemarthrosis
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How can you tell a hemarthrosis from a dislocation?
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A hemarthrosis displaces the humerus inferolaterally while an anterior dislocation displaces inferomedially
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What should you look for if you see a hemarthrosis?
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Subtle fracture of the humerus
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What if you can’t find a shoulder fracture and the patient has post-traumatic shoulder pain?
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You need to go to CT; the shoulder is complex
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How many pelvic fractures are associated with sacral fractures?
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Half
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Where should you look for sacral fractures on plain films?
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Look at the arcuate lines of the sacrum for asymmetry
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What do sacral stress fractures look like on plain films?
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May be patchy or linear sclerosis without cortical disruption (CT will almost always show the cortical disruption)
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What do sacral stress fractures look like on radionuclide bone scans?
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Honda sign
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What do stress fractures look like on MRI?
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Area of diffuse low signal on T1WI’s
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How do you work up a suspected pelvic avulsion fracture?
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Don’t touch!
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Why is a pelvic avulsion fracture a "don't touch" lesion?
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Because they can look like malignancies on histo
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Which joints can have bony erosions as the result of DJD?
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TMJ, SI, AC, and symphysis pubis
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What do stress fractures in general look like on plain films?
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Sclerosis in a weight bearing bone that has a horizontal or oblique linear pattern
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How are stress fractures treated?
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Rest, continuing activity can cause breakage
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Which patients may have occult femoral neck fractures?
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The elderly
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What should you do for an elderly patient with hip pain and negative plain films?
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Get an MRI—you can’t rule out femoral neck fractures with plain films
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What view should you get to look for a tibial plateau fracture?
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Cross-table lateral
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Why should you get a cross-table lateral when looking for tibial plateau fractures?
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-It may show a fat-fluid level
-This indicates a fracture that has leaked marrow into the joint |
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What if you can’t find a tibial plateau fracture?
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Get a CT or MRI, these can’t be ruled out on plain films
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What is a Lisfranc fracture?
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-Fracture-dislocation of the tarsometatarsals
-If the dislocation is slight, it can be easily overlooked |
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How do you look for normal alignment of the tarsals?
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The medial border of the 2nd metatarsal should always line up with the medial border of the second cuneiform
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Who gets Lisfranc fractures?
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People who get their forefoot stuck in something (a hole, a stirrup) or diabetics with Charcot joints
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What is the Bohler angle?
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Normal anatomic landmark that should be assessed in every trauma foot film
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What does a narrow Bohler angle indicate?
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If it’s less than 20 degrees, there’s a compression fracture of the calcaneus (seen in jumpers)
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