Final

Question 1

List the three presentations/types of osteoporosis

Answer 1

1. Generalized (Senile/Postmenopausal)
2. Regional
3. Localized

Question 2

List the characteristics of Generalized Osteoporosis (Senile/Postmenopausal)

Answer 2

• increased bone radiolucency
• cortical thinning; “pencil thin” cortices & endplates
• endplates look very white compared to radiolucent vertebrae
• altered trabeculae patterns
1. horizontal lines disappear
2. accentuated vertical trabeculae = “pseudohemangiomatous” appearance
• “Pancake” and anteriorly wedged vertebrae
• Bioconcave endplates
• Isolated end plate infarction
• Schmorl’s nodes (intrabody discal herniations)

Question 3

List the characteristics of Regional Osteoporosis

Answer 3

dt disuse/immobilization, reflex sympathetic dystrophy

• Acute & Painful: progressive pain, swelling and atrophy
• Usually develops in one area distal to trauma site
• Osseous hyperemia dt neurovascular imbalance
• Patchy, mottled
• Metaphyseal localization
• No joint dz

Question 4

Cause of Localized Osteoporosis

Answer 4

dt infection, inflammatory arthritis, neoplasm

Question 5

What is the most common cause of generalized osteoporosis?

Answer 5

o Age
The leading cause of osteoporosis is a lack of certain hormones, particularly estrogen in women and androgen in men. Women, especially those older than 60 years, are frequently diagnosed with the disease. Menopause brings lower estrogen levels and increases a woman’s risk for osteoporosis. Other factors that may contribute to bone loss in this age group include inadequate intake of calcium and vitamin D, lack of weight-bearing exercise, and other age-related changes in endocrine functions (in addition to lack of estrogen).

Question 6

What is the standard imaging modality to quantify bone mineral density?

Answer 6

DXA (DEXA/dual energy x-ray absortiometry)

Question 7

What causes rickets and osteomalacia?

Answer 7

Primarily due to a deficiency in vitamin D, which may be dt malabsorption
Osteomalacia also involves abN levels of calcium and phosphorus metabolism, and also may be dt dietary deficiency, renal dz, and a small group of miscellaneous dz
Note that rickets has two other forms: renal osteodystrophy with chronic
renal disase, and renal tubular defect (a failure to reabsorb phosphate in urine, so it doesn’t become mineralized in the bone).

Question 8

What are the classic radiographic features of rickets?

Answer 8

• Generalized osteopenia (bowed appearence)
• Coarse trabecular changes
• Widened growth plates (tall, thick; with palpation feels thicker, swollen up)
• Rachitic Rosary (rosary – bead appearance; sternum looks like line of beads)
• Absent zone of provisional calcification
• Frayed “paintbrush” (edge margin close to growth plate) and cupped metaphyses

Question 9

What causes scurvy and what are the classic radiographic features?

Answer 9

o Vitamin C def.
o Radiographic features
• White Line of Frankel – dense zone of provisional calcification - @ end of metaphysis – (vs. frayedpaintbrush w/ Rickets)
• ring epiphysis (Wimberger’s sign)
• Pelken’s spurs—a spur at the end of the bone (outcropping of BN @ metaphysis)
• scorbutic zone (Trummerfeld zone)
• subperiosteal hemorrhages dt def. of intercellular cement which in turn promotes vascular fragility

Question 10

What are the classic radiographic features of hyperparathyroidism in the spine, skull, and hand?

Answer 10

• Spine
o Subperiosteal resorption
• Hand – Radial margins of the proximal and middle phalanges of 2nd and 3rd digits with acroosteolysis (appears as a jagged edge)
• Skull
o “Salt and pepper” resorption of lamina dura
• Hand
o Osteopenia
o Trabecula accentuation
o End plate concavities
o “Rugger Jersey” spine (thick cortical area)
o Widened sacroiliac joints

Question 11

What are the face, skull, and foot changes seen with acromegaly?

Answer 11

• Face:
• prominent forehead
• Sinus overgrowth
• Widened mandibular angle (prognathism)
• Skull
• Sella turcica enlargement dt pituitary neoplasm
• Sinus overgrowth
• Malocclusion
• Foot: heel pad greater than 20 mm (about 1 inch)

Question 12

What osseous changes might long term corticosteroids cause?

Answer 12

• Osteoporosis of Cushing’s dz
o Cortices wll be thinned, density diminished, deformities
o Bioconcave end plate configurations
• Osteonecrosis
o In femoral & humeral heads; in distal femor and talus
o “Intravertebral vacuum cleft sign”; Gas in the vertebra with avascular necrosis leading to collapse of the vertebae

Question 13

The “H”-shaped vertebra is classically seen in what condition?

Answer 13

Sickle Cell Anemia:
•vertebral bodies are osteoperotic; deformities at endplates (“step off”, “fish vertebrae”, “H” vertebrae, w/ central depression (hypoplasia of central portion of vertebrae)

Question 14

What are some complications to the skeleton secondary to sickle cell anemia?

Answer 14

The bone changes dt marrow hyperplasia, ischemia and necrosis.
• Generalized osteoporosis (marrow hyperplasia)
o Thin cortices
• Coarse trabeculae, especially in axial skeleton
• Large vascular channels
• Widened medullary cavity
• Epiphyseal ischemic necrosis
• Medullary infarcts (metaphysic or diaphysis)
• Secondary salmonella or staph aureus osteomyelitis
• Vertebral body collapse
• Posterior mediastinal extramedullary hematopoiesis

Question 15

Which anemia tends to result in “honeycomb” trabecular patterns?

Answer 15

Thalassemia

Question 16

Hemophilic arthropathy typically occurs in which joints?

Answer 16

Knee, ankle, and elbow (bilateral and symmetrical)

Question 17

What is a common differential diagnosis when encountering hemophilic arthopathy?

Answer 17

Rheumatoid arthritis

Question 18

Which condition demonstrates nonuniform joint space narrowing, osteophytes, subchondral sclerosis, & subchondral cysts?

Answer 18

DJD

Question 19

Which condition presents with triangular sclerosis only at the iliac portion of the lower SI joint?

Answer 19

Osteitis Condensans Ilii

Question 20

Is osteitis condensans ilii more commonly unilateral or bilat?

Answer 20

• bilat & symmetric sclerosis (the text says asymmetric (364)

Question 21

Is osteitis condensans ilii more commonly found in males or females?

Answer 21

• predominantly women of childbearing age

Question 22

Osteitis pubis is commonly associated with which medical procedure?

Answer 22

• surgery near the pubic symphysis→ usu fr operations on the lower urinary tract (suprapubic or retropubic prostatectomies)

Question 23

What is the difference b/w marginal & non-marginal syndesmophytes?

Answer 23

Syndesmophyte – An osseous excrescence attached to a ligament
• Non-Marginal Syndesmophytes – don’t come from corners
o Psoriatic (esp at thoracolumbar jxn) & Reiters
o the syndesmophytes tend to skip levels w/ psoriatic & reiters
• Marginal syndesmophytes – ossification of outer annulus fibrosis leading to thick, vertical radiodense areas; They connect adjacent vertebrae. In AS, they bow outward slightly, giving the spine the bamboo stick appearance
(vs the spondylophytes found in DJD)
• AS (bamboo spine – formed fr extensive syndesmophytes)
• AS & Enteropathic the syndesmophytes tend to be continuous

Question 24

Which spinal arthritides have marginal vs non-marginal syndespmophytes?

Answer 24

• Marginal: AS

* Non-marginal: Psoriatic Arthritis, Reiter’s syndrome

Question 25

What systemic condition is commonly found in pts w/ diffuse idiopathic skeletal hyperostosis (DISH)?

Answer 25

• Diabetes • Dyslipidemia • Hyperuricemia x-ray of cervical spine reveals large bridging anterior osteophytes from the level of C2 to the upper thoracic spine (yellow arrow). Additionally, a dense band of calcification is noted along the posterior aspect of the vertebral bodies. (red arrow) Mild disc space narrowing is noted at C5-6 and C6-7, with minimal narrowing at C3-4. There is no evidence of facet joint fusion or narrowing.

Question 26

Dysphagia is common in which arthritic condition & why?

Answer 26

DISH – spinal involovment, esp ALL, & extraspinal ligamentous & tendonous calcification & ossification – much trouble swallowing if involves ALL (note: this condition has relative maintenance of the disc height and absence of posterior joint fusion or sacroiliitis; there is also ossification of the PLL) • Ekatrina also found • Hydroxyapatite deposition disease • Calcific tendinitis (bursae, ligament, capsule) • Longus colli • anterior to C2 and C3 bodies, inferior to anterior tubercle of C1 • RPI (retro-pharangeal interphase) may increase • Self-limiting (transient) • Acutely symptomatic • Pain, stiffness, muscle spasm, painful dysphagia • Acute onset, increase over 2-5 days, gradually resolve over 1-2 weeks; radiographic findings resolve • Similar process occurs in IVD (intervertebral disc) of children INTERVERTEBRAL DISC DEGENERATION • a.k.a. spondylosis • Loss of disc height • Osteophytes (spondylophytes (in spine)) • Endplate sclerosis • Vacuum phenomenon (cleft) (sign of degeneration, lucency in disk) • Retrolisthesis (MC cause is DJD) • Central stenosis uncommon (MC cause is facet degeneration vs disk degeneration)

Question 27

List the radiographic findings of Neurotrophic Arthropathy:

Answer 27

``` • joint changes that occur secondary to loss of sensation • Hypertrophic Type: the 6 D’s: 1. Distended Joint 2. Density Increase of subchondral bone 3. Debris or loose bodies 4. Dislocation 5. Disorganization Joint 6. Destruction of articular cortex (there is also the abbreviated 3Ds dislocation, destruction & degeneration) ``` • Atrophic type: Atrophic – resorbtion 1. complete resorption of articulating bone end, leaving a sharp transverse demarcation at the metadiaphysis which has been likened to surgical amputation (often in the proximal humerus) 2. tapers the bone end to a sharp pencil point

Question 28

Which conditions may result in neurotrophic arthropathy:

Answer 28

* These stem from impaired pain perceptions or proprioception with repeated unrecognized trauma * DM * Alcoholism * tabes dorsalis (results from syphilis slow breakdown of all or part of the body and the progressive loss of reflexes) * paralysis * syringomyelia (esp UE) – cavity inside canal filled w/ CSF * Essentially severe, destructive DJD

Question 29

What is synoviochondrometaplasia?

Answer 29

• A benign disorder marked by metaplasia of hyperplastic synovium to hyaline cartilage • The hyaline cartilage calcifies or ossifies and detaches from the synovium to form loose bodies (<2-3 cm in diameter) within the joint, tendon sheath, or bursae in which it forms • Involves large wt-bearing joints • Most common in knee; occasionally bilateral • Never in the spine • Radiographically o Multiple radiodense loose bodies in the joint capsule, less commonly a tendon sheath or bursae o Pressure erosions, widened joint space, and secondary degeneration • Sx: intermittent pain, joint swelling, stiffness, and episodes of “joint locking”

Question 30

Name the commone sites of involvment of RA in the hand & wrist:

Answer 30

``` Hands: • MCP’s & PIP’s; marginal erosions (irregular, no sceroltic margin) • radial margins of 2nd & 3rd MC head • Boutonniere (DIP extend, PIP flex) • Swan neck deformities (DIP flex, PIP extend) • Ulnar deviation at MCP joint Wrist: • Ulnar Styloid erosion • uniform loss of radiocarpal joint • erosions of triquetrum-pisiform • spotty carpal sign • pancarpal involvement • scapholunate dissociation ```

Question 31

What is a marginal erosion?

Answer 31

irregular, no sclerotic margin (on sides of metacarpal heads – radial sides more) • Marginal erosions: bare area; up to 1 yr; extend to central portions • Erosions - gout

Question 32

What is the significance of widening of the atlanto-dental interspace?

Answer 32

Text pg. 478: “can lead to direct compression of the brainstem or cause neurological damage by excessive kyphosis • Cervical (MC) spine involvement in 50-80%; few at T/L junction • Odontoid/dens erosions • C1-C2 instability → neurologic damage (enlarged; N <5 in child); atlanto-axial subluxations • Pseudobasilar invagination • Facet involvement; stair-stepping (anterior-lysthesis; can get with DJD as well) • IVD involvement

Question 33

Which conditions demonstrate laxity of the transverse ligament?

Answer 33

The inflammatory arthirtides tend to affect tendons & ligaments rather than joint membranes as with the degeneratives (enthesophy) →possible w/ RA (but uncommon), ???? - SLE, Down’s syndrome

Question 34

Is SI involvment common in RA?

Answer 34

No – if so, there is usually minimal sclerosis; uni or bilat & asymmetric

Question 35

Describe the radiographic difference b/w RA & Psoriatic Arthritis in the hand & wrist:

Answer 35

Psoriatic looks similar to RA w/o hyperemia PA: • DIP and PIP jts of the hand • Ray pattern: effects all jts of a single digit • ST swelling • Fluffy periostitis • "Pencil in cup" deformity • marginal erosions and tapered bone ends • Asymmetrical with uniform joint space loss RA: • MCP’s (Haygarth’s nodes) & PIP’s • marginal erosions (irregular, no sceroltic margin, Rat bite lesion) • radial margins of 2nd & 3rd MC head • Boutonniere (DIP extend, PIP flex) • Swan neck deformities (DIP flex, PIP extend) • Lanois deformity • Ulnar deviation at MCP joint • Bilateral and symmetrical and uniform joint space loss • (Most common Protusio Acetabuli in pelvis)

Question 36

What is the gender incidence of the vertebral column & pelvis in ankylosing spondylitis?

Answer 36

male 9:1 and Onset at 20-60 yo (peak 40-50 yo)

Question 37

What is the 1st site of involvement of the vertebral column & pelvis in AS?

Answer 37

* Pelvis: iliac side & lower 2/3 (synovial portion) of the SI joint; symmetrical * Spine: thoracolumbar jxn

Question 38

What is the 2nd site of involvement of the vertebral column & pelvis in AS?

Answer 38

Text pg 493: Spondlititis occurs in about 50% of patients and as a rule develops after SI dz, with thoracolumbar and lumbosacral junctions being the most common initial target sites.

Question 39

Is SI involvement usu uni or bilat in AS?

Answer 39

bilateral and symmetrical

Question 40

What is the gender incidence of AS?

Answer 40

Male 9:1

Question 41

What condition demonstrates squaring of the vertebral body?

Answer 41

AS

Question 42

What is the shiny corner sx?

Answer 42

• Increased radiodensity of the corners of the vertebral body related to osteitis • reactive sclerosis that is seen in AS Text: “bone sclerosis at the anterior vertebral margins associated with Romanus lesions in patients who have AS (ps- A Romanus lesion is an erosion found at the insertion of the outer annulus fibrosus into the anterior corners of the vertebral bodies seen in AS)

Question 43

What is a “carrot stick” fracture:

Answer 43

fracture of an ankylosed segment in AS→ usu causes paralysis

Question 44

Which condition demonstrates similar SI jnt & vertebral column findings to AS?

Answer 44

Enteropathic Arthropathy Ulcerative colitis, Crohn’s disease; Whipple’s disease, Salmonella, Shigella, Yersinia

Question 45

Which 2 seronegative spondyloarthropathis demonstrate non-marginal syndesmophytes & peripheral arthritis?

Answer 45

Psoriatic & Reiters | Non-marginal syndesmophytes—thicker, not throughout the spine like AS

Question 46

Reversible deformities of the hand are seen in which condition?

Answer 46

Systemic Lupus Erythematous (SLE)- ie: may have ulnar deviation, like RA, but pt can overcome w/ mm contraction or pushing hand down onto a table, etc; there are not erosions of the hand (SLE – get reversible deformities; because it is ligaments that are lax, but jts are not destroyed; not reversible with RA, etc.)

Question 47

What is acro-osteolysis & which condition demonstrates this finding?

Answer 47

resorbtion of the extremities (ie: distal phalanx) as seen in psoriatic arthritis

Question 48

What is the overhanging margin sign & which condition is this seen in?

Answer 48

Pathopneumonic finding in Gout → sclerotic margin outside the joint capsule

Question 49

What structures are primarily involved in CPPD (calcium pyrophosphate dehydrate crystal deposition disease)?

Answer 49

* fibrous & hyaline cartilage of the knee, wrist, & pubic symphysis * Fibrous – found in meniscus and triangular in shape * wrist and ulna – thick, irregular, mb poorly defined menisci, triangular cartilage * pubic symphysis, snnulus fibrosis * Hyaline (end of bones): parallel to cortex, thin, linear)

Question 50

What structures are primarily involved in HADD (hydroxyapatite deposition dz)?

Answer 50

Shoulder & Hip MC; calcification a short distance from insertion of a tendon; the MC spot is the supraspinatous tendon or bursa

Question 51

What is the most common source of osteoblastic metastatic carcinoma in adult females?

Answer 51

Breast CA

Question 52

List the three common causes of solitary sclerotic vertebral body.

Answer 52

Aka. Ivory Vertebra 1- Hodgkin’s Lymphoma (anterior body scalloping) 2- Osteoblastic metastastic → ** Most Common 3- Paget’s Disease (cortical thickening and expansion) Hint: Can’t differentiate end plates

Question 53

Is it common to find a tumor involving a joint?

Answer 53

NO. If the joint is involved think of arthritic disease before tumor

Question 54

Is multiple myeloma more common in the vertebral body or neural arch?

Answer 54

MC vertebral body (text book pg. 819)

Question 55

What malignancy demonstrates as a cold bone scan?

Answer 55

Cold bone scan means that it looks normal on bone scan; this is how you DDx multiple myeloma from mets o Multiple myeloma

Question 56

Which is the most dense primary malignant bone tumor?

Answer 56

• Multiple myeloma, Osteosarcoma (2nd most common), Condrosarcoma (3rd most common, kid), Ewing’s (4th most common, kid)

Question 57

What is the common age range of primary osteosarcoma?

Answer 57

75% occur in 10-25yo; in older patients – likely dt malignant degernation of a benign process, but there is a second peak

Question 58

What is the difference between sunburst and onion skin appearance?

Answer 58

Essentially: Sunburst is periosteal “spokes of a wheel” pattern & Onion skin is a layered periosteal rxn Sunburst -- skull lesions (hemagiomas) often round or oval; lytic with striations in “sunburst” or “spoked wheel” “Onion skin” reaction = layered or laminated periosteal reaction created by severeal parallel concentric layers or lamellae of periosteal new bone  it implies a more aggressive process but is encountered in both benign and malignant disease  it is most characteristic of Ewing’s tumor (Ewing’s sarcoma) but mb found in osteosarcoma, acute, osteomyelitis, stress fractures and eosinophilic granuloma in very young patients A “sunburst” or divergent periosteal reaction is characteristic of osteosarcoma  The spicules of bone are more irregular and coarser than those encountered in the hair-on-end pattern  Hair-on-end pattern = uniform, fine, parallel linear shadows oriented perpendicular to the cortex -- characteristic of Ewing’s sarcoma

Question 59

Which part of the bone is commonly involved in osteosarcoma?

Answer 59

Metaphysis of long bone – esp distal femur, proximal tibia, proximal humerus (around the knee is most common)

Question 60

What is Codman’s triangle?

Answer 60

o Periosteal bone formation mb interrupted or may incompletely cover the surface of a lesion; periosteum lifts off the cortex -- often the case in osteosarcomas o A triangle consisting of several layers of periosteal reaction may form at the margin of the lesion = Codman’s Triangle o Codman’s triangle was at one time thought to be pathognomonic of bone sarcomas, but it is also encountered in osteomyelitis o The triangle is composed entirely of periosteal reaction and is usu free of tumor • it should be avoided as a site of biopsy Spiculated periosteal reaction and Codman's triangle. A patient with Ewing's sarcoma involving the mid femoral shaft demonstrates both spiculated periosteal reaction (open arrow) and Codman's triangles (solid arrows).

Question 61

Why is Ewing's sarcoma commonly found in the diaphysis of long bone?

Answer 61

B/c it arises from the red bone marrow, which is mainly in the diaphysis and is closely related to reticulum cell sarcoma o Mimics the radiographic appearance of the “round cell” tumors, leukemia & metastatic neuroblastoma (pg. 168-169)]

Question 62

What is geographic appearance?

Answer 62

Geographic Lytic appearance – Geographic = confined to a relatively specific area that is more or less easily defined; o More likely a benign process

Question 63

Which condition presents with solitary exostosis that points away from the nearest joint?

Answer 63

Osteochondroma (supercondylar process points towards the elbow joint)

Question 64

Compare the incidence of malignant transformation in osteochondroma and hereditary multiple exostosis.

Answer 64

Osteochondroma: 1% malignant transformation HME: 20% malignant transformation

Question 65

What is a corduroy vertebra?

Answer 65

= lytic lesion with coarse vertical striations o usu only happening at 1-2 vertebral bodies – whereas osteoporosis may have similar appearance but will be at more levels o occurs with hemangiomas (may look like Paget’s disease, osteoporosis)

Question 66

Is spinal hemangioma commonly solitary or polyostotic?

Answer 66

Solitary

Question 67

Which is the most common benign bone tumor of the spine?

Answer 67

Hemangioma (for the entire body it is the osteochondroma)

Question 68

Is a bone island (endostoma) symptomatic?

Answer 68

No it is usu asymptomatic; any bone except skull

Question 69

Which condition demonstrates pain worst at night and easily relieved by aspirin?

Answer 69

Osteoid Osteoma (benign)

Question 70

Which part of the bone is usually involved with osteoid osteoma?

Answer 70

``` Can occur in any bone  Cortical – most common  Cancellous  subperiosteal o 50% in femur and tibia, esp proximal femur o 20% in phalanges o 10% in spine  mostly neural arch ```

Question 71

What is the appearance of the tumor matrix in enchondroma?

Answer 71

``` Presents with stippled matrix calcification and endosteal scalloping Geographic lytic o Expansile o Thinned cortex, endosteal scalloping o Metaphyseal- diaphyseal o Most central o Calcification in 50% o No periosteal rxn, no soft tissue mass ```

Question 72

What is multiple enchondromatosis called?

Answer 72

Ollier’s Disease (& Maffucci’s syndrome but also has soft tissue hemangiomas/phleboliths)

Question 73

What is the most common location of fibrous cortical defect?

Answer 73

``` Most common sites: o Lower extremity (90% in tibia or fibula) o Humerus o Ribs o Ilium Usually in the cortex ```

Question 74

What is a fallen fragment sign?

Answer 74

Happens with simple bone cysts • Since 2/3 of simple bone cysts undergo pathologic fractures this is when you see a fallen fragment sign  a piece of bone can be seen on Xray below the pathologic fracture • A piece of the cortex falls into the cyst (if it doesn’t fall down, called a trap door sign) From book: o the partial internal septations may fracture and inferiorly migrate Bone cysts with a pathologic fracture mb notes to contain a spicule or fragment of bone in the dependent portion of the lesion = fallen fragment sign (although not common, it is quite characteristic of a simple bone cyst )

Question 75

Which benign bone tumor is named according to its appearance rather than its histological composition?

Answer 75

ANEURYSMAL BONE CYST | • Cystic, blood filled cavity; “aneurysmal” due to appearance

Question 76

Described the radiographic difference between an enchondroma, simple bone cyst, aneurysmal bone cyst and osteochondroma.

Answer 76

Endochondroma – Small round or oval cystic defects, typically with stippled matrix calcification and endosteal scalloping; discrete islands of cartilage surrounded by layers of bone. These occur within bone. Long bone lesions are more likely to be painful. Periosteal chondromas occur next to the cortex and under the periosteum Simple Bone Cyst – Oblong, central, expansile, radiolucent subepiphyseal osteolytic lesion. At times the partial internal septations may fracture and inferiorly migrate (“fallen fragment” sign); may be fluid filled of uncertain etiology; clinically silent unless fractured. Aneurysmal bone cyst – Osteolytic with soap bubble appearance; Widely expansile defect of the cortex with cortical buttressing at the region of expansion from the host bone and very thin corticies at the outer edge of the lesion. Cavities are filled with extravasated blood. Pain & swelling. These may be secondary to trauma or concurrent to other tumors. Osteochondroma – Sessile or pedunculated (“coat hanger” exostosis or “cauliflower cap” cartilage capped bony outgrowth that is continous with underlying bone; abN outgrowth of lateral portion of the growth plate; affects epiphyseal growth.

Question 77

Is giant cell tumor painful?

Answer 77

Yes

Question 78

Is Paget's disease monostotic or polyostotic?

Answer 78

• Polyostotic (= more than one bone involved)

Question 79

List the radiographic features of Paget's disease in a long bone

Answer 79

Plain film usu diagnostic; bone scan can identify additional sites o ’d or ’d bone density o coarsened (thickened, less distinct) trabeculae o thickened cortex (less distinct) o bone expansion o subarticular extension o pseudofractures (ie stress fractures through the bone) o deformities Skull: osteoporosis cirumscripta; cottonwool appearance Spine: picture frame vertebra (endplates are thickened/cortex thickened) & ivory vertebra Pelvis: brim or rim sign (obliteration of Kohler’s teardrop) Femur and tiba: blade of grass or candle frame appearance; V lesion; saber shin deformity; shepard’s crook (thickened, bowing femur)

Question 80

List some common sites for avascular necrosis/osteonecrosis

Answer 80

Epiphyseal, Metaphyseal/diaphyseal

Question 81

List 5 typical causes of avascular necrosis/osteonecrosis.

Answer 81

Appearance: areas of sclerosis, lucency, collapse. Crescent sign is pathognomonic for AVN. Spontaneous Osteonecrosis of the Knee (SONK) Legg-Calve-Perthes Disease-AVN in children’s hips Keinboch’s Disease-AVN of lunate, dt trauma Osteochondritis Dessecans Osgood-Schlatter’s Disease-not actually AVN

Question 82

What part of the spine is DISH most commonly found?

Answer 82

Thoracic spine, lower cervical, upper lumbar, superior SI joint

Question 83

What is the most common organism responsible for bone and joint infection?

Answer 83

Staph Aureus

Question 84

What terms are used to describe bone and joint infections?

Answer 84

Osteomyelitis and septic arthritis