MSK Flashcards
Which fracture is associated with a peri lunate dislocation?
Scaphoid (60%)
Capitate subluxes dorsally
What is midcarpal dislocation. what ligament is damaged? What associated fracture ?
capitate is dislocated dorsal and nudges the lunate volarly but it is not fully dislocated
Ligament = Triquetrolunate interosseous ligament
Associated with Triquetral fracture
What ligament is damaged in a lunate dislocation?
Lunate dislocated volar direction
Ligament damaged = Dorsal radio lunate ligament
What happens in DISI?
**Dorsal intercalated segmental instability **
Happens with SL ligament injury
WIDENING (>80) of the Scapholunate angle
The Lunate tilts DORSALLY and the scaphoid tilts volar
What happens in VISI?
Volar intercalated segmental instability
Rare, happens with lunotriquetral lug injury.
Lunate and Scaphoid tilt Volar
ACUTE scapholunate angle <30
What is bennetts fracture?
Fracture base of the first metacarpal
Pull of the abductor pollicus longus (APL tendon causes dorsolateral dislocation
Nb a comminuted # base of 1st metacarpal = ROLANDO
What is gamekeepers thumb?
Avulsion fracture of the base of the proximal first phalanx
Ulnar collateral ligament disruption
STENER lesion = when adductor tendon gets caught in the torn edges of the UCL = Surgery
Monteggia and Galeazi fracture?
MUGR
Monteggia - Fracture of the proximal ulna, anterior dislocation of the radial head
Galeazzi - Radial shaft fracture, with anterior dislocation of the ulna at DRUJ
What is cubital tunnel syndrome?
Swollen ulnar nerve within cubital tunnel retinaculum
Accessory muscle can cause = Anconeus epitrochlear
Where is hills sacs deformity?
Posto-lateral humeral head impaction fracture (anterior dislocation)
Where is stress and bisphosphate fractures at the femoral neck?
MEDIAL = stress fracture
LATERAL = Bisphosphonate
Segond fracture?
Lateral tibial plateau
Associated with ACL tear (75%) and internal rotation
MR SL = Medial Reverse Lateral Segond
Reverse Segond fracture?
Medial tibial plateau
Associated with PCL tear with external rotation. Associated with medial meniscus injury.
MR SL = Medial Reverse Lateral Segond
Arcuate sign ?
Avulsion of the proximal fibula
Associated with PCL tear
What is classic association with patellar tendon tear (alta)?
SLE (elderly, trauma, RA)
bilateral patellar rupture = chronic steroids
What is tillaux fracture?
Salter-Harris 3 = through the anterolateral distal tibial epiphysis
What is triplane fracture?
Salter-harris 4 =Vertical component through the epiphysis , horizontal component through the physis , oblique through metaphysis
What is Maisonneuve fracture?
Medial tibial malleolus with disruption of the distal tibiofibular syndesmosis.
most X ray and look at the proximal fibula = # proximal fibular
What is bohlers line?
line drawn between the anterior and posterior borders of the calcaneus
< 20 ? fracture
Jones Fracture?
Fracture base of 5th metatarsal
**1.5cm distal to the tuberosity @ metaphysis-diaphysis junction
What is the most common fracture of the base of 5th metatarsal?
Avulsion
Peroneus brevis
Patterns of Lis francs fracture/dislocations?
Homolateral = all tarsal move lateral
Divergent = 1st MT goes medial and 2-5th goes lateral
Fleck sign = in-between the 1st and 2nd MT = avulsion of the LF ligament
LF ligament connects the medial (1st) cuneiform to the 2nd metatarsal base on plantar aspect
Common Lytic bone lesion? FEGNOMASHIC
Fibrous dysplasia
Enchondroma/ Eosinophilic granuloma
GCT/Geode
Non-ossifying fibroma
Oestoblastoma
Mets/myeloma
ABC
SBC
Hyperparathyroidsim (brown tumour)
Infection/infarction
Chondroblastoma/chondromyxoid fibroma
Commonest location of enchondroma ?
Hands/feet
Intramedullary and metaphysis
If pain think pathological fracture
DDx Brown tumor (hyperparathyroidism), sarcoid, intraosseous ganglion, metastatic disease.
Maffuci - multiple enchondroma + haemangioma
Olliers - multiple enchondroma only -affect the metaphysis
Cartilaginous rest - radiolucent streaks
What is bizarre parosteal osteochondromatous proliferation (BPOP) aka Nora’s lesion?
Exostosis post trauma of the periosteum of the phalanges
Chondrosarcomas may be secondary to what lesions?
Osteochondromas and enchondromas
Chondrosarcomas occur in the pelvis, femur and humerus.
Most well differentiated, low grade
Paraneoplastic hyperglycaemia
Lobular growth
High 2 signal
ring and arcs/chondroid matrix islands on CT
Soft tissue extension
**endosteal scalloping. **
if no mineralized matrix = aggressive/high grade
How to tell enchondroms from chondrosarcoma ?
Endosteal scalloping more than 2/3 cortex
Pedunculated lesion arising from surface of bone with continuity of normal cortex and marrow
Osteochondroma
points away from the joint
Metaphysis/metaphyseal equivalents (rarely diaphysis)
Multiple =
Trevor’s - epiphysis locations and single lower limb
Diaphyseal aclasia/Multiple Hereditary Exostoses - Metaphysis region of tubular bones of extremities
Cap > 2.5cm ??? chondrosarcomatous transformation
ng. avian spur points towards the joint
Name three most common malignant tumours?
Myeloma
Osteosarcoma
Chondrosarcoma
What are the main types of oestosarcomas?
Intramedullary (85%)
Parosteal
Periosteal
Telangiectatic
What are features of intramedullary osteosarcoma
Femur (40%) and proximal tibia commonest sites (15%)
**Aggressive periosteal reaction **
- Sunburst
- Codman triangle
- Lamellated (onion skin)
**High grade = Met to the lung
**
Reverse zoning phenomenon - dense mature matrix in the centre, less peripherally
Nb ewings Sarcoma - not likely ot have reverse zoning and not sunburst, more lamellated. cortex can be intact
What are key features of a telangiectatic oestosarcoma?
Distal Femur
Haemorrhagic and necrotic components
Fluid-fluid levels
Thus, heterogenous on T1 and T2
*Purely lytic but with aggressive features
Solid components enhance
DDx
ABC
—Expansile lytic lesion arising in metaphysis
—No tumour nodularity and enhancement
- Thin peripheral and septal enhancement
GCT
—Mildly expansile metaphyseal lesion with extension to joint line
—Can be very aggressive and have soft tissue extension
What are key features of a parosteal sarcoma?
Big +++
**Posterior distal femur (metaphysis) **
Marrow extensions (50%)
Early adult and middle age
*string sign Lucnet cleft between bone and mass. This is not present in Periosteal sarcoma
Low grade
What are the key features of a periosteal sarcoma?
Diaphyseal
Likes **medial distal femur **
Large enhancing soft tissue component
Usually, no marrow extension
Nb Intermediate grade ie worse prognosis than parosteal but better than conventional
20, lytic lesion eccentric, sclerotically marginated, lobular, expansile lesion extending from the metaphysis to the epiphysis with internal septations ?
chondromyxoid fibroma
look for internal septations
Eccentric
DDx GCT
- very similar, similar location (eccentric, originates in metaphysis, extends to subarticular region)
-rarely has sclerotic margin
DDx ABC
-Fluid/fluid levels MRI and thin walled
DDx Non-ossifying fibroma
-Cortex based rather than eccentric intramedullary
multicentric lesions involving the anterior tibial cortex. mixed sclerotic and lytic components.
Adamantinoma
Low-grade, malignant lesion most frequently arising in tibial cortex
*Cortically based lesion in anterior tibia
What is ‘triple sign’ in synovial sarcoma?
Heterogeneous signal (combination of low, intermediate, and high) T2 signal from:
Solid mass
haemorrhage + necrosis
calcification (1/3).
Bowl of grapes sign = multiloculated appearance of mass with internal septa
Heterogenous enhancement of the solid components.
little to no perilesional oedema
Classic history -
paediatric patient with a multi-cystic appearing mass with well-defined margins around the knee joint
NOT in joint ie DOESNT arise from the synovium. Close to joint
what are the features of a well differentiated liposarcoma?
*>75% fat content
*thickened septa
*small soft tissue nodularity
commonly located in the retroperitoneum
if develops a clear cut separate nodular dominant focus > 1 cm = de-differentiated
if < 20
= Myxoid liposarcoma often shows a classic myxoid background (T2/STIR-bright) with some nodular soft tissue
and adipose tissue components. Don’t confuse for cyst!!!
Young male with nocutrnal pain that improves with aspirin, which bone lesion?
Osteoid osteoma
**nidus > 2cm = osteoblastoma **
= Posterior elements
Nb** Osteoblastoma can have have soft tissue expansion/involvement**
Double density bone scan
“Dripping candle wax” is a buzzword for what bone lesion?
Melorheostosis
Bone within a bone - ‘Dripping candle wax’
= irregular continous cortical hyperostosis along margins of femur
Fibrosis of overlying skin (dermatomal pattern) - Flexion contractures
Can cross joints
A Shepherd’s Crook Deformity is most typical for what lesion?
Polyostotic fibrous dysplasia
Fibrous dysplasia =
long, expansile lesion with mixed density ranging from lytic to *ground glass .
‘long lesion in a long bone’.
Typically medullary, with expansion,
Monostotic is most common FD
2 conditions assocated with polyostotic FD
1. McCune- Albright - Cafe-au-lait, precocious puberty
2.Mazarbrauds
+ intramuscular Myxomas in adults
Monostotic is most common FD
Difference between a simple bone cyst and anuerysmal ?
ABC
- Eccentric in location
- More pronounced Fluid-fluid levels
- More expansile
- Can be 2o = giant cell tumor, chondroblastoma, and osteoblastoma
SBC
- Centered in medulla
- Classic HUMERUS and long bones
- Fallen fragment sign
- Present with pathological fracture
Nb in small bones, phalanx, metacarapls - appear identical
Chondroblastomas are most common in which age group and in which location?
Epiphyseal regions long bone
(or epiphyseal equivalent - Patella, calcaneus, trochanters, tuberosities, tarsal and carpal bones)
Males < 20
Lytic lesion
-eccentric
- arising epiphysis or apophysis.
-skeletally immature patient - +/- internal Ca2+ **
-Extensive perilesional edema and enhancement in marrow MRI**
Not a child or adolescent
adult clear cell chrondrosarcoma
Non-ossifying fibromas are most common in what age group and in which location?
children/adolescences
Distal tibia and femur in a
metadiaphyseal,
*Cortical
well defined,** sclerotic margins** , can also **have internal septations **
If <2-3 cm in size this may be termed a fibrous cortical
defect.
NOF may also heal and become completely sclerotic
DDX
ABC - MRI ‘fluid - fluid’ levels.
GCT
Doesnt typical extent to the epiphysis (like GCT)
GCT non -sclerotic margin
Growth plates closed
chondromyxoid fibroma
- both sclerotic margins and internal septations
-eccentric intramedullary
differential considerations for vertebra plana?
Mnemonic is MELT.
Metastasis/Myeloma, Eosinophilic granuloma, Lymphoma, Trauma/Tuberculosis.
What are features of GCT?
-Physis closed.
-Non-sclerotic margins
-originated in epiphysis and extends to metaphysis.
-Abuts articular surface
-Eccentric
-‘Soap bubble’
If in spine = sacrum
Fluid-fluid level on MRI
DDx
+Chondroblastoma
- Skeletal immature usually
- originates in epiphysis rather than metaphysis
- chondroid matrx
- Sclerotic margin common + periosteal reaction
-Extensive regional edema
+Chondrosarcoma
+ABC
old lady with sudden medial knee pain after raising from chair?
SONK
types of stress fracture of the medial condyle of femur
High risk locations for stress fractures to progress to complete/displaced fractures?
Compressive side =less risk
Tensile side = more risk
Tensile side
- femoral neck (lateral)
- transverse patellar fractures
- anterior tibial midshaft fracture
5th metatarsal
talus
navicular
sesamoid great toe fracture
Osteomalacia vs rickets?
Rickets = Child: growth plates (physes) wide, frayed, and cupped
Osteomalacia = Adult: Looser zones (late finding), smudgy and ill defined trabeculae
Osteochondrosis?
Kohlers = Navicular
Frieberg = 2nd Metatarsal
Severs = Calcanael apophysis
Blount = proximal medial tibial epiphysis = ‘Bow leg’
Perthes = Femoral head (4-8)
Scheuermann disease = Vertebral apophyses. multiple wedged vertebrae and thoracic kyphosis
Preiser = scaphoid
Kienbock = Lunate (20-40, associated with negative ulnar variance)
Panners = Capitellum (5-10, throwers)
Tenosynovitis extensor compartments?
RA = 6th (extensor carpi ulnaris)
De Quervans = 1st compartment- (extensor pollicis brevis and abductor pollicis longus)
Intersection syndrome = 1st and 2nd extensor compartments cross over - extensor pollicis brevis and abductor pollicis longus with extensor carpi radialis brevis and longus.
multi flexor tendons = RA
Main finger tumors - Glomus, GCT of tendon sheath and fibroma, what are the features?
Glomus - T1 dark, ~T2 bright, avid enhancement
extrinsic erosion of underlying phalanx
GCT of tendon sheath - T1 and T2 dark, blooming artifact
**GCT of tendon is form of PVNS **
Fibroma - T1 and T2 dark, no blooming
Subungual exostosis - bony outgrowth with cortical and medullary continuity from the parent bone. Can arise following trauma. Adolescences
What is type 4 SLAP tear and why is it important ?
when extends to the biceps anchor = surgical Mx
What can cause an acute flat foot deformity?
Posterior tibial tendon injury
Scar, synovitis in anterolateral recess of ankle?
anterolateral impingement syndrome
after inversion injuries/ anterior talofibular ligament
meniscoid mass - low on T1 and T2
Tear to the talocalcaneal ligament and inferior extensor retinaculum of the foot.
Sinus tarsi syndrome
obliteration of sinus tarsi fat
associated with RA and flat foot/PTT tear
Normal marrow conversion ?
see image
Marrow signal on MRI ?
see image
Pattern of marrow reconversion?
**low T1 signal red marrow **which remains reasonably bright (less signal drop out than yellow marrow) on STIR or other fat saturated sequences.
High T1 signal fatty yellow marrow
The pattern of marrow reconversion is the exact reverse of the initial conversion, so beginning at the ends of the long bones and spreading to the diaphysis.
widening interpedicular distance?
see image
shoulder positions for US?
see image
patterns of sacroiliitis
Bilateral and symmetrical
- AS
- IBD
Bilateral and asymmetrical
- Gout
- Reiters
- Psoriatic
osteitis condensans - female, bilateral, symmetric, triangle-shaped sclerosis of ilium at sacroiliac joint
Unilateral
- infection
- rarely SAPHO
causes of anterior vertebral scalloping?
AAA
TB
Lymphadenopathy
Developmental motor delay
causes of posterior vertebral scalloping?
SATAN
Syringomyelia/Dural ectasia
Acromegaly
Tumours - (ependymoma, lipoma , dermoid, neurofibroma)
Achondroplasia
NF - 1
also
Connective tissue disease - marfans, ehler danlos
Mucopolysacchardoses - hurlers, murquio - VERTEBAL BEAKING
Commonest skeletal/Spinal abnormality of NF-1?
–Scoliosis (from plexiform neurofibromas)
–Posterior vertebral scalloping
–Dural ectasia
– Lateral thoracic mengiocele
– Foraminal narrowing, Hypoplastic pedicles and posterior elements (remodelling from mengiocele)
– Intramedullary or extramedullary intradural NF’s
features of Haemophilia arthopathy?
Dense hemarthrosis
Epiphyseal overgrowth
Erosions & joint space narrowing
**Hypertrophied synovium due to haemosiderin (GRE blooming ++) and low on all signals
Widened intercondylar notch**
Rare pseduotumour =
Large expansile or lytic bubbly lesion with mass effect on adjacent tissues/scalloping on bone
What is the features of nail-patella syndrome?
Bilateral iliac ‘horns’
absent/hypoplastic patella’s
Broad horizontal acetabulum
Features of pagets?
Osseous expansion
Thickening of cortex
Coarse trabecular pattern
Skull - osteoporosis circumpripta (lytic phase)
Skull - sclerotic phase - Enlargement of skull: widening of diploic space, involvement of inner and outer tables
‘tom o shanter’ sign
Brown = well defined cortical lesion with no periosteal reaction
Also in lytic phase - blade of grass or flame shaped lucent bone lesion
Features of osteopetrosis ?
Diffusely dense bones (marble bone)
Features of lipoma Aerborescans
kids
chronic inflammation of the synovium leading to extensive fatty infiltration of the synovium
high on T1 and T2 but suppress on fat-saturated sequences.
**Post-contrast the synovium itself will enhance. **
Treatment is by synovectomy.
Features of SAPHO
Synovitis: anterior chest wall, unilateral sacroiliitis
Acne: hydradenitis suppurativa, acne conglobata
Pustulosis: palmoplantar pustulosis (50%)
Hyperostosis: enthesopathy, sclerosis
Osteitis: inflammatory changes, pain
Sternoclavicular hyperostosis
Nuclear medicine bone scan, bilateral uptake in the sternoclavicular joints and manubrium is called a** ‘bull’s head’ sign**
Unilateral sacroiliitis may also occur
Absent thumb, Hypoplastic radius, VSD?
Holt-Oram syndrome
PONGS diseases with normal mineralisation?
Psoriartic arthritis
Osteomyelitis
Neuropathic
Gout
Sarcoidosis
Features of gauchers?
Erlenmeyer flask - Metaphyseal flaring
H shaped vertebrae
Osteonecrosis/AVN- femoral and humeral heads
-serpiginous sclerotic areas or a bone-within-bone appearance
Hepatosplenomegaly is common and co-existent with thrombocytopaenia and anaemia secondary to bone marrow failure
diffuse marrow replacement with low signal T1
100 times more common in Ashkenazi Jews
DDX sickle cell
- no splenomegaly, rather small calcifoed spleen
- Hx acute bone crisis
- posterior mediastinal mass (extramedullary haematopoiesis)
MSK Features of Rheumatoid arthritis?
Synovitis/soft tissue swelling
Periarticular oestopenia
**Marginal erosions **
Uniform joint space narrowing
Deformity late stage
**No bone proliferation **
Proximal distribution in hands
-MCP, and PIPJ- typically first
- Carpals, Radiocarpal,
Hip
-concentric loss of joint space, osteoarthritis (OA) = superior loss of joint space
-acetabular protrusion
Shoudler girdle
-erosion of the distal clavicle
-marginal erosions of the humeral head: the superolateral aspect
-“high-riding shoulder” = subacromial-subdeltoid bursitis
- high incidence of rotator cuff tear
Spine
-erosion of the dens
- atlantoaxial subluxation
- atlantoaxial impaction (cranial settling): cephalad migration of C2
- erosion and fusion of uncovertebral (apophyseal joints) and facet joints
DDx
Amyloid arthropathy can be similar distribution and pattern of erosions.
However amyloid classically preserves joint space, unusual for periarticular osteopenia and LARGE and excessive subchondral cyst formation
Features of Psoriatic arthritis?
**Distal - Favours DIPJ and IPJ>MCP **
**Mixed - Erosive changes and bone proliferation **
Sausage digit (dactylitis)
Pencil in cup
No osteoporosis - NORMAL bone density
Outside hands-
-Ivory phalanx
-Altanoaxial subluxation
-Spondyloarthropathy -
Bulky paravertebral ossification, asymmetric with skips
Sacroiliitis: bilateral but asymmetric
DDx
Reiters
- Same appearance of bilateral but asymmetric sacroiliitis
- Same bulky paravertebral ossification
Feautres of Ankylosing spodylitis ?
Thin vertical syndesmophytes with concomitant bilateral sacroiliitis
‘Bamboo spine’
‘Shiny corners’
Joints widen first before narrows
Enthesopathy - calcified tendon insertion sites
‘Dagger sign’ - spinous process fusion
Early features are far more subtle and require a higher index of suspicion, which include,
MRI-
-Enthesopathy - high signal on MRI at tendon insertion sites
-Romanus lesions - triangular shaped oedema at the corners of vertebral bodies
-Andersson lesions - bony oedema in the vertebral bodies adjacent to the disks.
-Oedema in the sacroiliac joints.
Sequences = T1 fat sat and STIR, coronal SIJs and sagittal spine
T1 fat sat - useful for visualisation of bony erosions and new bone formation
T1 fat sat post contrast - useful for detecting bone marrow abnormalities (but so is STIR, so contrast is not an absolute requirement for imaging ankylosing spondylitis).
STIR - useful for detecting bone marrow abnormalities in the SIJs and spine
T2 fat sat - useful for detecting oedema
Extra-articular
-Upper lobe predominant ILD, fibrobullous disease
-aortic root dilatation, aortic regurgitation, pericarditis
DDx
- IBD associated arthritis -
- Axial - Identical appearance of sacroiliitis and spondylitis to AS
- IBD enthesopathy often calcaenus
Features of CPPD?
Overlaps with OA but atypical Joints
-Patellofemoral and not medial/lateral compartment
Wrist: radiocarpal joint
Hand: MCP joints, particularly 2nd and 3rd
Chondrocalcinosis (not invariably present)
Hook osteophytes of metacarpal heads
Subchondral cysts common, may be large
Scapholunate advanced collapse wrist SLAC*- Degenerate SL ligament
Disorders assoicated with CPPD - 4 Hs
- hypothyroidism
- haemochromatosis
- hyperparathyroidism
- hypomagneseia
DDx
Haemochromatosis
-Younger males, similar distribution to CPPD
- Both ‘hooked’ oestophytes - of the radial aspect of the 2nd and 3rd MCP
Features of Gout?
Typically men >40
Spares joint space (until late)
Juxta-articular erosions (punched out) with Overhanging edges
Soft tissue tophi
Features of Hyperparathyroidism ?
**‘Subperiosteal bone resorption’ radial 2nd and 3rd fingers **
**Terminal tuft erosions/resportion = Acro osteolysis
**
Brown tumour: expansile, nonaggressive lytic lesion with geographic Non sclerotic margins
Superior and inferior rib notching
Rugger jersey spine/osteosclerosis is associated with secondary hyperparathyroidism
chondrocalcinosis and CPPD
1° hyperparathyroidism (HPTH): parathyroid adenoma (75-85%)
2° HPTH: chronic kidney disease most common
Nb Renal osetodystrophy is 2° HPTH and oestomalacia
Features of JIA?
Before 16
Proximal
Premature closure of the physis
large effusions
erosions
Cartilage destruction & joint space narrowing (JSN)
End-stage ankylosis
Carpus most frequent site of fusion
Widened intercondylar notch
DDx
Haemophilia
TB
Psoriatic arthropathy
Feautres of SLE arthopathy?
Nonerosive, reducible deformity of digits
Osteoporosis, high rate of osteonecrosis (ON)
DDx
Jacouds
- similar apperance but Post rheumatic fever
DDx for Ivory vertebrae
see picture
DDx Atlanto-axial subluxation?
see picture
Upper and lower limb myotomes
see picture
upper and lower limb dermatomes ?
Disc buldges
see picture
Osteoporotic vs metastatic vertebral body fracture
see picture
TB vs Staph discitis?
see picture
Dashboard injury?
see picture
Hyperextension injury to the knee?
see picture
anterior aspect of the tibial plateau and femoral condyles
Pivot shift injury?
see pic
Clip injury
see picture
Patellar dislocation injury pattern?
see pic
Head injury NICE
see picture
DDx for Erlenmeyer flask deformity?
see picture
Bone lesions <30 and >30
see picture
Osteopoikilosis, osteopathia striata, pyknodysostosis?
Osteopoikilosis
Metaphyseal or epiphyseal foci of dense lamellar bone that resemble bone islands
**Pyknodysostosis **
Severe sclerosis involving entire skeleton but medullary space is preserved
- short stature
- small mandibular size and beaking of the nose
-Wormian bones
-acro-osteolysis with sclerosis (-acro-osteolysis with sclerosis)
osteopathia striata
Striated intramedullary densities, often metaphyseal
‘stalks of celery’
contents of popliteal fossa and borders ?
Medial to lateral
Popliteal artery
Popliteal vein
Tibial nerve
Common peroneal nerve
Superomedial border: semimembranosus
Superolateral border: biceps femoris
Inferomedial border: medial head of gastrocnemius
Inferolateral border: lateral head of gastrocnemius and plantaris
Describe the menisci?
Both menisci are C shaped and are attached at both ends to the intercondylar area of the tibia.
The medial meniscus is also fixed to the medial collateral ligament and the joint capsule. As a consequence of this injuries to the medial collateral ligament are often accompanied by a tear of the medial meniscus.
The lateral meniscus is smaller and does not have any extra attachments, rendering it fairly mobile.
Myositis ossifcans calcifcation pattern?
It begins as amorphous calcification and then develops a sharper cortical margin after approximately 2 months.
Periosteal reaction may or may not be present but crucially there is no erosion of the underlying cortex, a fact which discriminates it from malignant fibrous histiocytoma.
string sign
Unlike a parosteal osteosarcoma, this plane will extend along the whole length of the mass completely separating it from the bone.
Parosteal osteosarcoma may have scalloping
Contents of the lumbar plexus?
‘I (twice) Get Lucky On Fridays’:
Iliohypogastric nerve
Ilioinguinal nerve
Genitofemoral nerve
Lateral femoral cutaneous nerve
Obturator nerve
Femoral nerve
biconcave vertebrae?
see picture
problem with the development of the ulnar side of the distal end of the radius. The distal radioulnar joint subluxes and the ulna displaces dorsally. proximal carpus is V-shaped
Madelung deformity
growth failure of the distal radius, by comparison the ulna appears lengthened (Positive ulnar variance).
appearance is of a V-shape to the radioulnarcarpal joint with angles of <120 considered characteristic.
Mnemonic = DIGIT
D = Dysplastic - Ollier disease, osteochondromatosis, achondroplasia, mucopolysaccharidoses, diaphyseal aclasis
I = Idiopathic
G = Genetic - Autosomal dominant.
50% of patients have bilateral deformities.
Most common association is Turner syndrome
I = Infection
T = Post-Traumatic
Features of multiple myeloma
1) Plasmacytoma - solitary lytic lesion - spine, pelvis , skull
2) Myelomatosis - Diffuse skeletal involvement - oestolytic lesions with discrete margins
3) Diffuse skeleteal oestopenia - no lytic , predominantly in the spine (this type can have multiple compression fractures)
4) Scelorsng myeloma - with sclerotic bony lesions , associated with POEMS syndrome
Myeloma has poor uptake on bone isotope scans
Features of hypertrophic osteoarthopathy
Periosteal reaction, usually along shafts of tubular bones in extremities
Generally symmetrical
Location
Tibia, fibula, radius, ulna are most frequent
Less common in phalanges
3-phase bone scan
Typically linear symmetric ↑ uptake along margins of long bones: parallel track sign, tram line sign, or double stripe sign
types of osteogensis imperfecta?
Almost alwas type 1 or 4
Type 1 most common
- Blue sclera
- normal stature
- Hearing impairment
Type 4
-small stature
-usually normal hearing
Calcaneonavicular vs talocalcaneal coalitions
see picture
