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Flashcards in Musculoskeletal 3 Deck (42):

lumbar spine

Plain films - AP, lateral – standard

Special views: lumbrosacral spot, oblique

Approach – ABC’S (alignment, bones, cartilage, soft tissue)
-Spinous process alignment (AP)
-Intrapedicular distance (AP)
-Transverse processes (AP)
-Vertebral body width (AP)
-Vertebral body height, width, cortex (Lateral)
-Posterior vertebral line (Lateral)
-Disc spaces (Lateral)
-Soft tissue (Both)
-Free stuff (Both)


Bohler's angle - calcaneus

-A=Superior surface of posterior tuberosity, subtalar articulation
-B=Superior tip of subtalar articular surface and anterior process


patellar tendon rupture

-Cannot extend lower leg at knee
-High-riding patella
-Mechanism: sudden muscle contraction (direction change) or direct blow


the pelvis

-Single AP view is common
-Judet views - supine, hip 45d -acetabulum
-Inlet - 40d caudad - pelvic ring
-Outlet-40d cephal - sacroiliac
-CT has largely replaced
special views if fx suspected


Alignment: the mortise

-The mortise is critical!
-When describing ankle fractures,
always comment on the mortise.
-Is it intact? Wide? Narrow? Where?
-Determines ligamentous disruption and overall stability of the ankle.


hip dislocations

-90% are posterior
-Femoral head lateral, superior to the acetabulum
-Lower extremity internally rotated and shortened
-Axial force along flexed hip and knee
-Sciatic nerve injury 10%
-Anterior Dislocation → External rotation, Shortened, Femoral head is inferior, medial



-Bony defect of the pars interarticularis
-Non-displaced fracture
-L4-L5, L5-S1
-Repetitive stresses, congenital, kids
-Fracture results in a "collar" around neck of the “Scotty Dog”
-Lateral oblique view


Burst fracture

-Axial load - jump, fall
-Comminuted, entire vertebral body, both anterior and middle columns
-Post vertebral line disruption
-Inter-pedicle space disruption
-Unstable=post column fx
-Fx fragment may have “retropulsion” into spinal canal and compress cord
-CT, MRI if neuro deficit


thoracic spine

-AP, lateral standard views
-T1 – T12: all have ribs
-L1: transverse process

-Fractures less common (rib cage support)
-Most: compression fx’s
-Significant mechanism

-Fracture/dislocation: 60-70% spinal cord, injury - all get MRI

-CT for fracture
-MRI for spinal cord


talus fracture

Uncommon – but serious

High force mechanism

Fracture/dislocation common

High risk AVN, malunion


CT all talus fx’s


Femoral shaft fractures

-High Energy/Force
-Pathologic fx?
-Displacement due to muscle contraction
-OR reduction, hardware common
-High risk of bleeding (femoral artery)
-High risk compartment syndrome


chance fracture

-“Seatbelt fx” - hyperflexion, force
-Thoracolumbar junction
-Horizontal fx thru body, post arch, SP
-Ligamentous injury
-May have retropusion of fragments


slipped capital femoral epiphysis

-Capital femoral epiphysis
slips - posterior/lateral
-10-15yo obese boys: hip/knee pain
-Salter-Harris Type I injury
-Risk for AVN


tibial plateau - compression fx

Can be subtle! Easy to miss!
-Usually lateral plateau
-Increase in trabecular density – sclerotic
-Tibia lateral to femur

-Direct blow “fender fx”
-Osteoporosis - minor mechanism
-Effusion, can’t walk


tibial pilon/plafond fracture

Fx of the Tibial Plafond

Comminuted Intraarticular Impacted

Vertical load - Jumpers

Unstable - Get CT scan

Plafond = “ceiling”. Fx of the “ceiling” of the ankle joint



-Anterior slippage of the vertebral column relative to the vertebral body below it
-True: Fracture of pars interarticularis with displacement
-Pseudo: no pars interarticularis fx
-Usually a result of bilateral spondylolysis
-Most commonly occurs at the L3/4, 4/5 or L5-S1 level
-Results in spinal stenosis


osgood-schlatter disease

-Micro-avulsion at insertion of patellar tendon at apophysis (cartilaginous tissue for tendon insertion)
-10-12yo - when tibial tubercle ossifies
-Family hx same
-Pain, inflammation
-Rest, good prognosis
-Can also occur at calcaneus, navicular (foot)


pelvis fractures: stable

-2/3 of all pelvis fx’s
-Avulsions common in athletes
-Isolated ischium, pubic ramus - fall, osteoporosis
-Sacral - fall, direct blow
-Illiac wing – blunt, MVA: Duverney’s


ankle xrays - the approach

-AABC’S (ABC = Adequacy, Alignment, Bones/Periosteum, Cartilage (joint space), Soft Tissue)
-Tibia, fibula, talus
-Malleoli - check medial, lat, posterior
-Mortise: ligament disruption - check width, symmetry
-Soft tissues
-Ottawa Ankle Rules
-Many Fx Classifications -Weber common
-Ligaments are key!


Bohler's and Gissane: calcaneus

-Decreased/Increased Bohler’s or Gissane’s Angle?
-Suspect fx
-Bohler’s commonly decreased
-Gissane’s commonly increased


tibial plateau

-Bumper, dashboard - auto vs. ped, MVA
-Axial load, valgus force - jumpers
-High risk of ligamentous injury
-Order CT scan
-Most require ORIF


true spondyloisthesis

-spinous process step-off above subluxed vertebral body w/ PI defect


greenstick/torus fx's

-Incomplete break in
cortex = greenstick fx
-Buckle, buldge, impaction along cortex = torus fx
-Common in kids: soft bones; radius/ulna


hip fractures - proximal femur

-250k/yr in US
-20% mortality in elderly
-Trauma, osteoporosis, steroids
-Location and displacement: key
-Displaced neck, subcapital fx’s: High risk AVN femoral head, Garden Classification)
-ORIF: pins to total arthroplasty
-CT, MRI for fx’s, MRI occult fx’s


hip hardware

1. Screws – stabilize, realign hip and preserve anatomic angle. Non-displaced and incomplete fx’s with little risk for AVN
2. Dynamic hip screw – stabilize, realign hip and preserve anatomic angle. Fx’s with little risk of AVN
3. Hemiarthroplasty – proximal femur preserved, femoral head/neck replaced, cup inserted into acetabulum. Used if high risk AVN
4. Total hip arthroplasty – replace entire proximal femur, add cup for acetabulum. Widely displaced, high risk AVN, poor quality native bone


Pediatric wrist is special

first to osssify

Spiral order

Roughly 1 carpal per year age up to age 7

Radial head epiphysis >age 3

Pisiform ~ age 12 – the last one


Trimalleolar fracture

-All 3 malleoli fx’d, including posterior
-(AKA: malleolus tertius)
-Unstable fracture
-Follow the cortical lines of both the tibia and fibula on lateral


calcaneus fracture

-Jumpers, axial load or fall from height
-Most common tarsal bone fracture
-Axial view calcaneus
-Decreased Bohler’s Angle, increased Gissane Angle
-Can be subtle! CT all
-Compression fx of lumbar spine common w/ these fx’s – axial load transfer. Get plain films L-spine too


Wedge compression fracture

-Hyperflexion, fall
-Osteoporosis, pathologic
-Loss of height anterior vertebral body only (anterior column)
-Posterior body height and post vertebral line intact
->% loss height = >severity
-Common - 1 in 4 >75yrs
-CT to r/o Burst fx


Salter-Harris Classification

Type I:
-Fx through epiphyseal plate, w/ or w/o displacementof the epiphysis.
-Difficult to detect w/o displacement

Type II:
-Fx through epiphyseal plate and metaphysis
-Most common type; up to 75%

Type III:
-Fx through epiphyseal plate and epiphysis

Type IV:
-Fx through epiphyseal plate, epiphysis and metaphysis

Type V:
-Impaction fx involving all/part of the epiphyseal plate
-Most serious growth consequences

-Note: epiphyseal plate is also called the physis or growth plate
-It is the radiolucent area/space between the epiphysis and metaphysis


Base of 5th metatarsal

Jones Fx
-Base 5th MT shaft at least 1.5cm from styloid
-Direct blow, repeated activity, stress
-High incidence non-union - Cast, ORIF

Pseudo-jones Fx (avulsion fx @ tuberosity)
-Common - “Dancer’s Fx”
-Avulsion peroneus brevis tendon (aka: fibularis longus)
-Fracture at styloid of 5th MT
-Walking cast


Pediatric elbow ossification

When do the bones first appear on xray?

-Capitellum 1yr (1-8mo)
-Radial head 3yr (3-6yr)
-Internal (medial) epicondyle 5yr (3-7yr)
-Trochlea 7yr (7-10yr)
-Olecranon 9yr (8-10yr)
-External (lateral) epicondyle 11yr (11-12y)


legg-calve-perthes dz

-Avascular necrosis of
femoral head, epiphysis
-Flat, irregular, sclerotic

-Boys: 4:1 predominant
-Age 4-9 most common
-LCP is idiopathic
-”growing pains”
-Limp, hip pain, often
knee pain


Salter-Harris fracture classification

Growth plate fx’s
in children

Can affect growth,
bony development

Higher number =
worse prognosis

I-V for us
I-IX for pediatric


Maisonneuve fracture

Spiral fx proximal
fibula with:
-Wide medial mortise
-Medial malleolar fx
-Tibiofibular joint
widening (syndesmosis disruption)
-With or without distal
fibula fx (classic)

Check proximal
leg tenderness
in all ankle injuries!


Pediatric considerations

-Growth Plates
-Salter-Harris Classification
-Wrist ossification order
-Elbow ossification order - CRITOE
-Slipped Capital Femoral -Epiphysis
-Ossification = when bones actually form or when you can see them on xray
-Metaphasysis is the active part next to the growth plate



-step off below subluxation, PI intact


Bimalleolar fracture

-Lateral and medial malleoli fractures. Posterior malleolus intact.
-Unstable fracture with mortise (ligamentous) disruption


patellar dislocation

-Often clinically evident, may self reduce
-Majority are lateral
-Xray for patella fx post-reduction
-30% w/ ligamentous, meniscus injury


Pelvis fractures: unstable

-Unstable = pelvic ring is disrupted in 2 or > places
-Diastasis = separation – SI joints or pubic symphysis
-High-risk injury - hemorrhage, pelvic organ injury
-The ring of the pelvis is fractured in 2 or more places – that alone makes it unstable
-High risk for hemorrhage! You can lose up to 2 liters of blood!


degenerative joint disease - spondylosis

-DJD, Osteoarthritis = Spondylosis
-Cortical sclerosis, disc space narrowing, spurs
-Ankylosing Spondylitis (bamboo spine)


Lisfranc fracture/dislocation

-Midfoot slide.
-Check: 1st, 2nd MT alignment w/ 1st and 2nd cuneiform:
-Check: 5th MT alignment w/ cuboid:
-Check: fx at proximal 2nd MT:
-Check: MT/cuboid spacing on AP/oblique
-Often the mechanism is extreme dorsiflexion at MTP joints – tip-toe position.
-Actual Lisfranc ligament is between first cuneiform and medial base of the second metatarsal bone