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Flashcards in Musculoskeletal 1 Deck (51):

Commonly missed fractures

-Stress fracture
-Scaphoid, elbow, radial head, midfoot, tibial plateau, hip; supracondylar and torus fractures in kids
-Non-displaced and impacted fractures
-Non-displaced growth plate fractures
-Suspect fracture but negative xray? (Dx: Probable fx. Immobilize, Repeat xray in 2-3 weeks – look for callous, CT, MRI or bone scan next)


Generalized decreased density = osteopenia

Diffuse lucency DDx: (think global process)

-Osteoporosis (late)

-Lung, renal, thyroid, breast CA

-Reflex Sympathetic Dystrophy Synd (RSDS)


fractures: general concepts

-Radiographs provide confirmation (Hx (mechanism), PE, PMHx, age are key)
-Know anatomy, know views (Order what you need, shoot it once)
-Confirm all “suspected” fractures on >1 view
-Lots of overlap - account for and mentally subtract overlying structures - all views


CPPD arthropathy



Myositis Ossificans

-Extra-skeletal ossification in soft tissue
-After blunt trauma
-Common in thigh
-Imaging: Xray, CT, MRI


septic arthritis - non-pyogenic

-M. tuberculosis, fungus
-Risks: IVDU, DM, steroids, TB risks
-Indolent, slow
-Osteoporosis common
-Spine, knee common
-Red, hot, painful joint. Plain film changes are late, but order one first.
-May see subchondral erosions, periosteal reaction (above)


Bones: decreased density (increased lucency)

Lucent (black) line: suspect fracture

Generalized lucency - Osteopenia
-Endocrine/metabolic disorders, steroids
-Hyperparathyroidism, osteomalacia, rickets
-Multiple Myeloma (disseminated form)

Focal lucency
-Osteolytic metastases, bone cysts, some tumors
-Multiple Myeloma (solitary form)


Open fracture (compound fx)

-High incidence of infection, osteomyelitis
-Crush injury: vascular complications, infection
-Irrigated and repaired in OR < 8 hrs
-Antibiotics, Tetanus
-Open tuft fx (exception to OR repair)
-Needs to be within 8 hrs!! EVERYONE GETS ABX AND TETANUS
-The only exception is tuft fx


bone tumors

-Where? Joint violated? (tumors don’t cross joints)
-Margin? Sclerotic/thin, well-defined vs. irregular, ragged
-Shape? Longer than wide (w/in medullary) or wider than long (burst through cortex)?
-Characteristics? Geographic, permeative, “moth-eaten”, expansile, “soap bubbly”
-Bony reaction? Lytic, sclerotic
-Periosteal reaction? Codman’s, mixed, onion skin
-Tumors dont cross joints! they stay in the bones they originated in


Bone scans - nuclear med

-Occult Fractures
-Stress Fractures
-Bone Infection
-Avascular Necrosis


erosive arthritis: gout

-Calcium urate crystals
-Sharp, sclerotic “punched out” or “rat bite” erosions near affected joint
-Acute monoarticular arthritis grt toe: Podagra
-Severe = tophi, periarticular erosions, “punched-out” lesions
-Tophi = soft tissue
-She will not require us to tell apart gout from rheumatoid etc. ON A PICTURE → will need to know the characteristics of them


CT scan: indications

-Complex, intra-articular fx’s (Characteristics, extent)
-Calcaneus, tibial plateau, talus, midfoot
-Spinal column
-Pre-op evaluation
-Occult fracture
-Associated injuries
-Tumors, infection
-Biopsy, interventional procedures


erosive arthritis: psoriatic

-At DIP, spares PIP
-Subchondral erosions
-Terminal phalanges narrow “pencil in cup”


Cartilage (joint space)

-Refers to joint spaces
-Normal appearance on xray views is key
-Widening: disruption, calcification, fluid
-Check if fracture extends into the joint (Intra-articular Fx)
-MRI best for ligamentous injury, disruption
-The joint space should be the same all the way around
-Intraarticular fracture means that the fracture extends into the joint space
-Decreased (Arthritis - most types, Impacted fx, dislocation)
-Increased (Fracture, dislocation, Hemarthrosis, Infection (pus))
-Chondrocalcinosis (Pseudogout, CPPD)
-Hemarthrosis – blood in the joint


Intra articular fractures

-Fracture enters joint
-Important distinction
-Cartilage damage
-Ligamentous injury
-Joint is now at risk for degenerative arthritis



-Check entire cortex, contour; size, shape of bones; check alignment
-Fractures (Lucent (black) line passes through cortex, Check entire cortical margin for disruption, Check for impaction (bulge, increased density), Acute Fx’s linear, jagged - edges not corticated, Fx’s should be visible on more than one view)
-Decreased density (lucency, osteopenia)?
-Increased density (opaque, sclerosis, impaction)? Generalized process or focal process?
-Break and fracture are the same thing!
-Contour is how the bone should look
-Torus fx is a buckle fracture → compression fracture
-If you see something that looks white, its not a fracture


Special views: plain xrays

-To highlight particular bones, angles, relationships, non-displaced fx’s, dislocation
-Confirm a questionable abnormality
-“Comparison views” - other side
-“Weight-bearing view” - AC joint, foot
-Perpendicular - axial plane (Patella, calcaneus, shoulder, wrist)



-Generalized decreased bone density
-Overproduction of PTH (>PTH-> hypercalcemia (plasma), Increase in bone resorption, Stones, bones, abdominal groans)
-Subperiosteal resorption of bone in fingers
-Subchondral resorption in distal clavicles
-“brown tumors”, “salt & pepper skull”
-Brown tumors: not really tumors or malignant. They are radiolucent areas of increased osteoclast activity from abnormal bone metabolism. Rare – associated with hyperparathyroidism


Pagets Disease

-Chronic inflammatory remodeling of bone
-3 Phases: Early lytic, Mixed, Osteoblastic (Dense, sclerotic bone changes late)
-Pelvis, skull, spine, tibia (spares fibula)
-Thickening of cortex
-Thick, sclerotic traebeculum
-Bone gets bigger overall (“hat don’t fit”)
-Pagets disease: bones get hairy looking! Scalp gets much thicker; IT SPARES THE FIBULA (generally)


Avulsion fracture

-Avulsion fx’s are caused by sudden torque on the ligaments. The ligament stays intact but pulls a piece of bone away. If small piece of bone pulled off, commonly called a “chip fracture”


Pathologic fractures

Fracture occurs because bone is weakened by underlying process:
-Bone tumor
-Bone cyst
-Lytic or sclerotic changes


erosive arthritis: rheumatoid arthritis

-Narrowed joint spaces
-Periarticular erosions
-Radiocarpal erosion
-Ulnar deviation



-Bone (matrix) formers: increase density, sclerotic appearance
-Reparative: heals fx’s,
-Reactive: produce bone in cortex (periosteal lesions) or medullary cavity



-Bone (matrix) resorbers: remove, destroy: decrease density, lucent appearance
-Can remove bone at 20x rate of formation
-“make room” for tumors, infection


soft tissues

-Effusions in joint
-Fat pad - blood or fluid in fat space (elbow)
-Calcifications in soft tissue - outside of bone, joint
-Foreign bodies


Codman's triangle

Characteristic of aggressive periosteal reaction
-Malignancy, osteomyelitis
-Spicule of bone at edge of lesion, lifts periosteum
-Forms a triangle with bone cortex


periosteal reactions

Osteoblasts respond to periosteal insult - localized

Non-aggressive – solid
-Fx healing, repetitive trauma (child abuse)
-Neoplasms (usually benign)
-Osteomyelitis, indolent infections

Aggressive - mixed pattern → usually bad
-Malignant tumors, infection
-Interrupted pattern, onion skin, spiculated, sunburst
-Codman’s triangle


septic arthritis - pyogenic

-Hematogenous or local process
-Risks: IVDU, trauma, prosthesis, steroids
-Monoarticular - knee, hip, hands - any joint
-Staph, GC
-Articular cartilage destruction
-Rapid progression
-Polyarticular - rare
-Red, hot, painful joint. Plain film changes are late, but order one first.
-May see subchondral erosions, periosteal reaction (above)


Alignment - dislocations

-Joint space disruption
-Complete, partial (subluxation)
-Risk for fx, vascular injury
-Reduction (Manually move dislocated bone back into place, Realigning fractures prior to immobilization)
-Post-reduction films – check for placement, fx during reduction
-Reduction is moving dislocation back into place
-What is attached to the bone? A ton of stuff!! Vasculature, etc.


description of fractures

Open or closed?
-Open = compound

Must look at all views!

-Which bone(s)?
-Where in the bone?
-“Head” proximal
-Proximal, middle, distal third of shaft, neck

Number of fragments
-Simple (2)
-Comminuted (>2)

Direction of fx line
-Transverse, oblique spiral, longitudinal

-Impacted, depressed

Special fractures
-Torus, greenstick, compression
-Name of fracture type



-Soft tissue swelling, Hx
-Focal lucent or destructive areas within the bone
-Focal periosteal reaction
-Acute, subacute or chronic
-Plain film poor, but initial test
-MRI best, bone scan next
-Bone biopsy diagnostic


MRI indications

-Spinal cord injuries
-Occult fractures (Hip (elderly), scaphoid)
-Tendons/Ligaments/ Soft Tissue (MR Arthrography - contrast study of joints, Pre-op evaluation)
-Certain complex fractures, infections
-Bone marrow abnormalities
-Avascular necrosis



-diffuse loss of bone density
-Decreased bone mass: generalized
-Women > men
-Elderly, post-menopause ETOH, steroids, smokers, renal failure, GI Dz, debilitation
-Plain film, BMD/DEXA, CT
-Risk for pathologic fracture
-BMD: bone mineral density test
-DEXA: dual energy xray absorptiometry


reading a film

General Approach:

-Bones + Periosteum
-Cartilage (joint space)
Soft tissue


Bones: increased density

Generalized increased density
-Multiple/diffuse osteoblastic metastases – prostate CA
-Osteopetrosis (“marble bone dz”)

Focal increased density
-Impacted fracture, fracture healing
-Localized osteoblastic metastases
-Avascular necrosis (Late finding, May see “crescent lucency” from a subchondral fracture)
-Paget’s disease (late finding)


bone tumor

-Periosteal reaction
-Hyperdense bone
-Organized mass with clear margins
-Codman’s triangle
-CT next test for: periosteal reactions, lucencies, increased density lesions


Fracture Healing

Affected by: Pt age/health, the site, number of fragments, immobilization, blood supply to site

Inflammatory Phase
-5 to 7 days
-Hematoma formation

Reparative Phase
-Callus formation
-4 to 40 days

Remodeling Phase
-70% of healing time
-Can last up to one year
-Callus is converted into bone


fractures: alignment

Describe position or movement of distal segment relative to proximal
-Displacement: Left or right movement away from mid-diaphyseal axis line
-Angulation: angle away from normal axial line (Posterior or Anterior (dorsal or ventral/volar), Medial or Lateral (varus or valgus))
-Rotated (internal or external)


Number and types of bones

-206 bones in the body
-Long bones - length > width
-Short (cuboidal) bones - wrist, foot
-Flat bones - skull, illiac bone, scapula
-Sesamoid bones - “accessory ossicles” (Small, rounded bones located in tendons (
-Irregular bones - vertebral bodies


Charcot joint

-hypertrophic form
-denervation of joint
-micro fx's, bone fragmentation
-joint destruction
-pt w/ DM most common


Delayed fracture complications

-Delayed union, Malunion, Nonunion
-Osteomyelitis – bone infection
-Avascular necrosis
-Myositis Ossificans - after blunt trauma
-Compartment syndrome of right forearm
-KNOW COMPARTMENT SYNDROME!!!! They don’t need all 5 Ps for them to have compartment syndrome
-Malunion → bad union, nonunion → not coming together


osteoarthritis (DJD)

-Narrowed joint spaces
-Osteophytes & Spurs
-Subchondral sclerosis
-Subchondral bony cysts
-Primary most common
-Secondary (Usually after trauma, Young, unilateral)


erosive arthritis: ankylosing spondylitis

-Syndesmophytes: bony bridges join corners of vertebrae
-“Bamboo spine”
-Erosions at the corners of vertebral bodies
-SI joint fuses first - ascends spinal column
-“Bamboo spine” on AP: syndesmophytes fuse anteriorly
-Sacroiliitis is hallmark, with HLA-B27 positive
-Syndesmophytes connect the vertebral bodies to each other (happens anteriorly mostly)
-HLA-B27 = rheumatologic blood test
-Disease of young men
-Measure progression with angle that they’re bent over


Imaging modalities

-Plain Films – initial test for bones (Trauma, pain, edema, decreased ROM, FB, Always at least AP, Lateral (orthogonal 90deg), Oblique is initial 3rd view (hand, wrist, ankle, foot, etc), Special views)
-CT Scan
-Nuclear Imaging


Pseudofractures - fake outs

-Nutrient vessels
-Sesamoid bones/ Accessory Ossicles (Smooth, round, sclerotic edges, Predictable locations: feet, hands, elbows, wrists, knees)
-Overlapping adjacent bones
-Skin folds
-Distinguishing characteristics: Location, well corticated margins, no disruption, not the tender area, see on one view only
-Sesamoid bones are almost always roundish and they are smooth. They are also in typical places: feet, hands, elbows, writs, knees


is the film adequate

-Name, date, L&R label, all views?
-Pt properly positioned (“True” lateral or “true” oblique? All structures seen in anatomical alignment? Special views taken properly?)
-Must know normal radiographic anatomy to evaluate normal alignment and position


Acute fracture complications

-Compartment Syndrome (Pulselessness, pallor, pain, parasthesia, paralysis (5 P’s))
-Local Infection - skin cellulitis
-Fat Embolism


Stress fractures

-Small breaks, repetitive stress, exercise or impact
-Most common in the
foot, lower leg
-Initial xray often neg
-Repeat xray → solid periosteal reaction in 10-14 days
-Bone scan
-Plain xray may show findings in 10-14 days (or longer)
-Bone scan may be positive in 6-72 hours
-Runners, gymnasts, army


primary bone tumors

-Pt age, location helps DDx: must biopsy
-0-10yrs – Ewing’s sarcoma, neuroblastoma
-10-20yo, long bones (Ewing’s sarcoma (shaft), Osteosarcoma (epiphysis: growth areas))
-20-40yo (Osteosarcoma, Giant cell tumor (epiphysis))
->40yo (Chondrosarcomas: Long bones 45%, pelvis 25%; Thoracic spine, Consider metastases from distant primary)



-Fracture not healed
-Residual angulation
-Callous not completely formed
-Why? (Delayed immobilization, Poor reduction, Surgery not available, Surgical error, Non-compliance, Systemic illness)


Avascular Necrosis

-Bone death d/t diminished blood supply
-Femoral head, humeral head, scaphoid, talus (Kids - hip pain)
-Increased density, sclerosis, bony collapse, patchy or crescent lucencies
-Fractures, steroids, sickle cell, collagen vascular Dz, Legg-Calve-Perthes Dz
-Plain film sensitive late
-MRI is imaging study of choice, bone scan next