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Congenital Skeletal Anomalies & Skeletal Dysplasias

  1. Rickets
    Faulty mineralization of the bone before the fusion of growth plate, i.e., during enchondral bone growth, is known as RICKETS.
    Clinical features include bone pain, tenderness, irritability, craniotabes, rachitic rosary, bowed legs, swelling of wrists and ankles and delayed dentition.
    Location: Metaphyses of long bones subjected to stress are particularly involved (wrist, ankles, knees)
 Radiological features include:
  • Poorly mineralized epiphyseal centers with delayed appearance
  • Widening and lengthening of growth plate (zone of provisional calcification affected) is earliest radiographic feature of rickets
  • Increased distance between end of shaft and epiphyseal center
  • Epiphyseal plates widening and irregularity
  • Fraying, splaying and cupping of metaphysis
  • Periosteal reaction
  • Indistinct cortex with coarse trabeculations
  • Metaphyseal spur projecting at right angles to metaphysis in the cortex
  • Additional features:
  • Bowing of long bones
  • Genu recurvatum
  • At costochondral junction, epiphyseal widening results in typical 'rachitic rosary'
  • Frontal bossing
  • Scoliosis
  • Slipped capital femoral epiphysis
  • Triradiate configuration of pelvis
  • Basilar invagination

Fraying and cupping of metaphyses
Metaphyseal dysplasias are of many types: Schmid, Jansen's, Pena, Vaandrager and McKusick metaphyseal dysplasia. Metaphyses of long bones are cupped and resemble rickets.
Hypophosphatasia is autosomal recessive congenital disease with low alkaline phosphatase activity causing poor mineralization.
Causes of cupped and frayed metaphyses are:
  1. Congenital infections (rubella, syphilis)
  2. Hypophosphatasia
  3. Achondroplasia
  4. Rickets
  5. Metaphyseal dysplasia
  6. Scurvy
  1. Scurvy

  1. Spurs (Pelkan Spur) = Metaphyseal spurs projecting at right angles to axis of shaft
  2. Subperiosteal hemorrhages = Diaphyseal Subperiosteal hematoma with calcification of elevated periosteum is the sure sign of healing (woody-legQ)
  3. Cortical thinning ("pencil-thin" cortex)
  4. QCorner sign of Parke = Subepiphyseal infarction or comminution causing mushrooming or cupping of epiphysis
  5. Osteoporosis = characteristically "ground-glass" osteoporosis
  6. Rarefaction zone of Trummerfield = Metaphyseal radiolucent zone on shaft side
  7. White line of Frankel = Metaphyseal zone of provisional/preparatory calcification also seen in lead or phosphorus or bismuth poisoning and in healing rickets
  8. QWimberger's sign = Sclerotic ring seen around the low density osteopenic epiphysis

  1. Congenital Syphilis
    Transplacental transmission cannot occur < 16 weeks gestational age.
    1. Diaphyseal Periostitis (commonest feature)
      1. QSaber tibia (anterior convex bowing of upper 2/3rds of tibia with bone thickening)
      2. Bone within bone appearance
    2. Metaphysitis
      1. Metaphyseal irregularities
      2. Metaphyseal fractures
      3. QWimberger sign (symmetrical focal destruction of medial portion of proximal tibial metaphysis, pathognomonic sign)
    3. Osteitis and osteomyelitis (symmetrical and bilateral involving multiple bones)
    4. Syphilitic dactylitis
    5. Skull lesions (frontal bossing due to diffuse thickening of outer table; purely sclerotic or mixed lesions with “hot cross bun” skull) Q
    6. Spontaneous epiphyseal fractures causing joint immobility due to pain (Parrot's pseudoparesis) Q
    7. Hutchinson’s triad (dental abnormalities, interstitial keratitis and 8th nerve deafness) Q
    8. Saddle nose, high palate, short maxilla
    9. Anaemia
  2. Epiphyseal Injuries
    Epiphyseal injuries are grouped according to the Salter-Harris classification, an important guide to both treatment and prognosis of any Particular fracture. Epiphyseal fractures usually occur through the zones of hypertrophicand degenerating cartilage cell columns.

Metaphyseal corner fractures are highly sensitive and specific for child abuse.


Type of fractures






Single heavy

QMarch/ fatigue (stress)



QInsufficiency (stress)

Abnormal (metabolic)



Abnormal (tumor)



  1. Perthes disease
    1. X-ray features:
      1. QLateral displacement of the femoral head, the Waldenstrom sign (prognostic indicator)
      2. Widening of affected hip joint space is however earliest signQ
      3. Subcortical fissure in the femoral ossific nucleus(Frog leg lateral viewQ)
      4. Reduction in the size of the femoral ossific nucleus of epiphysis
      5. Increase in density of the femoral ossific nucleus
      6. Metaphyseal broadening and irregularity
      7. QSagging rope sign
    2. CT features:
      1. QLoss of 'asterisk' sign (star-like pattern of crossing trabeculae in the center of femoral head)
    3. MRI features:
      1. Asterisk or double-line sign (sclerotic non-signal rim between necrotic and viable bone)
      2. Hip joint incongruity (lateral femoral head uncovering, laberal inversion, deformed femoral head)

Bone Tumors

Malignant Bone Tumors:
  1. Multiple myeloma
    QMost common primary malignant neoplasm in adults, which is followed by osteosarcoma.
    QAge: usually 5th to 8th decade
  • Location:
  1. QDisseminated form: vertebrae> ribs > skull > pelvis > long bones
  2. SQolitary Plasmacytoma: Vertebrae> pelvis > skull > sternum> ribs
  3. Radiographic features:
    1. QMultiple punched out widespread osteolytic lesions in skull, however classic 2-3 mm ‘rain drop’ circular lytic defects are not always evident
    2. But Mandibular involvement may be helpful indistinguishing it from metastases
    3. Blown out lesions of skull, long bones (persistent red marrow areas of proximal femora and humeri) and pelvis
    4. Soft tissue masses adjacent to area of lysis may be seen
    5. Localized areas of lucency in red marrow areas and generalized osteoporosis are tow cardinal features
    6. Diffuse osteoporosis can alone cause suspicion of this disease in an elderly patient
    7. Spinal myeloma: sparing of posterior elements, intervertebral disc spaces and articular surfaces with paraspinal soft tissue mass
    8. Sclerotic lesions are rare in multiple myeloma
    9. It is still one of the indication for skeletal survey in today’s era of modern imaging.
    10. Bone Scan features
    11. In multiple myeloma, 99m Tc products do not localize well in the destructive/lytic lesions (no osteoblastic activity, hence no uptake - cold spots).Q
  • Bone Scan features
    In multiple myeloma, 99m Tc products do not localize well in the destructive/ lytic lesions (no osteoblastic activity, hence no uptake - cold spots). Q
A superscan on bone scan implies that so much of the methylene diphosphate (MDP) is taken up by the bones that there is no significant excretion in the kidneys and bladder or uptake in the soft tissues. In a patient with cancer, a superscan implies widespread osseous metastases that cannot be individually distinguished but rather occupy almost the entire skeleton.
  1. Osteosarcoma:
    1. QMost common malignant primary tumor of bone in young adults and children
    2. 2nd most common primary malignant bone tumor after multiple myeloma
    3. QIt has bimodal age distribution: 10–25 years and > 60 years with M:F = 3:2 to 2:1
    4. Constitutes 15% of all primary bone tumors confirmed at biopsy.
    5. Location:
      1. Metaphysis is common site of origin (90–95%) with long bones affected in 70–80% cases; femur lower end (40–45%), tibia (16–20%) and 50–55% thus seen around knee; facial bones (8%), flat bones affected usually in age >50 years (ilium).
  1. Factors for Secondary Osteosarcoma
    1. Paget’s disease
    2. Diaphyseal aclasis
    3. Enchondromatosis
    4. Post-radiation
  2. Radiographic features
    1. Large Osteosclerotic lesion (90%)
    2. Osteolytic lesion (fibroblastic)
    3. Aggressive periosteal reaction (sunburst/hair-on-end periosteal reaction)
    4. Codman's triangle
    5. Moth-eaten bone destruction with cortical disruption
    6. Soft tissue mass with new bone formation (osseous/cartilaginous type)
    7. Physis does not act as barrier to tumor spread
    8. Spontaneous pneumothorax (due to subpleural metastasis)
    9. involvement, epiphyseal invasion, joint and neovascular involvement and distant metastasis
  3. QMR (preferred modality)
    1. Tumor of intermediate signal intensity on T1W1 and high signal intensity on T2W1
    2. Clearly defines marrow extent (best on T1W1), vascular involvement and soft tissue component (best on T2W1)
  4. Radionuclide bone scan (NUC):
    1. Intensity increased activity on blood flow, blood pool, delayed images (hypervascularity, new bone formation). Local extent, skip lesions, metastasis to bone and soft tissues detected. 
    2. QDoughnut sign (peripherally increased uptake with central photopenia on bone scan) is a classical feature. Soft tissue extension demonstrated especially on SPECT.
  1. Ewing’s sarcoma:
    1. Ewing's sarcoma is the highly malignant primary bone neoplasm having specific cytogenetic analysis, i.e., t(11,12), Q is a PNET with 75% patients being under the age of 20 years and having male predilection.
    2. Histologically small oval/round tumor cells are seen arranged in sheets with occasional rosette-like pattern and most tumors are PAS-positive indicating presence of glycogen in the tumor cells. Q
  • Radiological features:
  1. ILL-defined osteolytic medullary lesion involving diaphysis
  2. Extension along the length of the marrow with Permeative bone destructionQ
  3. Cortical saucerization
  4. Classical multilaminar periosteal reaction giving 'onion-peel' appearanceQ
  5. Codman's triangles with elevated periosteum, although classically seen in osteosarcoma
  6. Soft tissue mass disproportionately large compared to the extent of osseous involvement, resembling osteomyelitis
  7. Bone sarcoma metastasizing to boneQ
  1. Chondrosarcoma
    1. It is a malignant tumor originating in cartilage.
    2. Secondary chondrosarcoma arise in a pre-existing bony lesion like:
      1. Usually
        1. An Enchondroma (central type) or
        2. An Osteochondroma (peripheral type) and
      2. Rarely in
        1. Chondromyxoid fibroma                       
        2. Chondroblastoma                           
        3. Synovial chondromatosis
        4. Enchondromatosis                                 
        5. Maffucci’s syndrome                      
        6. Diaphyseal aclasis
    3. Age: Peak incidence is at 50 years age.
    4. Sex: Slight male predominance (M:F is 1.5:1)
    5. Common location: Flat bones (pelvis, scapula), proximal femur and proximal humerus.
    6. Radiological features:
      1. Lytic lesion with endosteal resorption, periosteal reaction, periosteal new bone formation and bone expansion
      2. Multilobulated appearance with well-defined scalloping of endosteal surface and cortical destruction in more aggressive lesions
      3. Soft tissue extracortical mass out of proportion to the size of the intraosseous lesion is characteristic
      4. QBeing a chondroid tumor, presence of calcification (dense/stippled/nodular/conglomerate popcorn-like/ring/arc-like calcification) is characteristic feature.
The prognosis of chondrosarcoma is good when complete resection is achieved before metastatic spread.
The tumor shows poor response to radiotherapy and cytotoxic drugs.


Most osteochondromas (cartilage cap tumor/exostosis) have cartilage caps no thicker than 5 mm, and a cap more than 20 mm in thickness is likely to be malignant. Destruction of part of a well formed calcified cap or ossified stem is also a radiological feature of Osteochondroma favoring malignant transformation.
  • Radiological changes in leukemia in childhood
  1. Diffuse osteopenia/osteoporosis (most common pattern)
  2. Q"Leukemic lines"—these are transverse radiolucent metaphyseal bands or thick lines seen just below the epiphyseal growth plate uniformly across the width of metaphysis and these become dense after treatment
  3. Osteolytic lesions of flat and tubular bones (multiple small) with moth-eaten bony destruction. Lytic lesions distal to knee/elbow in children are suggestive of leukemia rather than metastasis.
  4. Infrequent but smooth/lamellated sunburst type of periosteal reaction due to periostitis.
  5. Sutural widening.
  6. Very rarely metaphyseal osteosclerosis or mixed lesions.

Benign bone lesions

  1. Chordoma
    1. It is a destructive bone tumor believed to arise from ectopic remnants of notochord/ notochord cell rest.
    2. Its maximum incidence between 50-70 years.
    3. It is locally malignant with strong tendency to recur after excision.
    4. Predilection for sacral (50%) and cranial (40%) regions (the extreme ends of the axial skeleton);
    5. In sacrum at S4 and S5 and in cranium basisphenoid (clivus and dorsal aspect of sella) Q
    6. Above sacrum and below C2, chordomas are rare.
    7. Radiologically appears as a oval or lobulated well-defined purely lytic mass in midline, which may contain calcification and a soft tissue component.
    8. Recurrence rate is high but it metastasis occurs late.
    9. Chordoma at the base of skull carry best prognosis
  2. Eosinophilic granuloma
    1. QLeast severe form
    2. Monostotic involvement three times more common than polyostotic (>50% involve skull)
    3. Radiological features:
      1. Skull—round/oval lytic lesion with beveled edge. Button sequestrumQ
      2. QMandible—floating teeth sign
      3. Spine—thoracic affected mainly, vertebra planaQ, ghostly appearance of neural archQ.
      4. Pelvis—geographic defect
    4. Long bones—hole-within-a-hole lesionQ
  3. Fibrous dysplasia
    1. Its tumor like lesion of the bone (nongenetic)
    2. It can be
      1. Monostotic                    b.  Polyostotic
    3. The association of polyostotic fibrous dysplasia, patchy café-au-lait spots of skin pigmentation and sexual precocity, usually in girls, constitutes the McCune Albright syndromeQ.
    4. A medullary-based, minimally expansile lesion with “ground-glass” opacity and irregular but well-defined borders.
    5. In long bones, the location usually is diaphyseal or diametaphyseal, and the epicenter is centric or eccentric.
    6.  More expansile lesions cause endosteal scalloping and thinning that weakens the cortex. Lesional radiopacity is variable depending on the ratio of fibrous and osseous tissue.
    7. Homogeneous, featureless grey opacity is the classic “ground-glass” appearance of fibrous dysplasia, a term borrowed from the appearance of frosted or ground window glass that is uniformly opaque. Lesions are less commonly homogeneously lucent or sclerotic.
    8. Chronic changes secondary to bone weakness may lead to bowing of weight-bearing structures, fracture, and remodeling. The “shepherd’s crook” is the bowing deformity with varus angulation of the proximal femur.
Radiological features:
  1. Q ‘Ground-glass’ or radiolucent area of trabecular alteration in the long bones with patchy sclerosis and expansion with cortical thinning and endosteal scalloping
  2. Pathological fractures and deformities like ‘shepherd’s crook’ deformity of femoral necks
  3. Asymmetrical thickening of skull vault with sclerosis at the base with multiple lucencies
  4. Obliteration with groundglass appearance of paranasal sinuses
  5. Leontiasis ossea (marked facial deformity)
  6. Cortical destruction and insidious formation of a soft-tissue mass containing tumor matrix are characteristic of underlying osteosarcoma.
  7. Ring-like and spotty calcification of cartilaginous matrix is indicative of chondrosarcoma. Fibrosarcoma has no visible matrix and shows simple osteolysis
Extra Edge
QSmoky”groundglass” bony matrix is classical of FD
  1. Exostosis (osteochondroma)
  1. Most common benign bone tumorQ
  2. Most occur at the growing ends of the bones
  3. Their growth ceases after skeletal maturity
  4. Most osteochondromas (cartilage cap tumor/exostosis) have cartilage caps no thicker than 5 mm, and a cap more than 20 mm in thickness is likely to be malignant.
  5. Destruction of part of a well formed calcified cap or ossified stem is also a radiological feature of osteochondroma favoring malignant transformation.
Osteochondroma is the most common benign tumor of bone.
  • Multiple exostoses (Diaphyseal aclasis)
  1. QAutosomal dominant inheritance
  2. Multiple flat/protuberant exostoses particularly at the ends of long bones, ribs, scapulae and iliac bones
  3. Cranial vault spared
  4. Long bone exostoses point away from the adjacent joint
  5. Failure of remodeling of bone ends resulting in deformities like short distal ulna (reverse Madelung deformityQ)
  6. Sarcomatous change suspected if rapid increase in size, or pain occurs.
  • Enchondromatosis/ Multiple enchondromas/ Dyschondroplasia (Ollier’s disease)
  1. QNongenetic inheritance
  2. Asymmetrical shortening of affected bone/ limb with joint deformity
  3. Radiolucency particularly in metaphyses with expansion of affected bone
  4. Areas of calcification within lesions
  5. Reverse Madelung deformity
  • QEnchondromatosis with hemangiomas (Maffucci’s syndrome)
  1. Multiple enchondromas with cavernous hemangiomas in soft tissues
  2. Chondrosarcomatous metaplasia is recognized hazard (in 20% cases)
  1. Osteoid osteoma Radiological features
  1. Affects young people, 10–25 years of age.
  2. Classical clinical presentation is pain during nighttime, which is relieved by aspirin.
  3. 50% are in femur or tibia, predilection for spine in 10% cases, usually in neural arch (sclerotic pedicle); however it can occur in almost any bone.
  4. Usually cortical, but may be intramedullary or subperiosteal.
  5. Diaphyseal lesion.
  6. CQortically located lesions. Lucent nidus surrounded by reactive sclerosis. May have central fleck of target calcification in the centre.
  7. Intramedullary lesions. Lucent nidus may be the only visible abnormality.
  8. Spinal lesions: Most often affects lamina. 60% are in lumbar spine. Mature sclerotic lesion may present as sclerotic 'Ivory pedicle' or 'ivory lamina'.
  9. CT better for diagnostic imaging.
Radionucide bone scan may show “double density sign”.
  1. Chondroblastoma
  1. Rare neoplasm
  2. Typically located in epiphysis of long bone
  3. Other Epiphyseal origin tumors are:
  1. Osteoblastoma
  2. Subchondral Cyst
  1. Generally benign
  2. 80% occur in 2nd decade
  3. Usually located eccentrically in epiphysis but may straddle the growth plate
  1. QClassical ‘Chicken-wire’ calcification may be seen on HP.                                         
  2. QX-ray- Spherical and well-defined lytic lesion with fine sclerotic margin.
  3. QCentral punctate calcification is seen in only 10% cases.
  4. Most common in femur followed by humerus and tibia.
  1. Chondromyxoid fibroma:
    1. 10-30 yrs age
    2. Metaphyseal eccentric
    3. Proximal shaft of tibia most classical site.
    4. It is eccentric without lobulations.
    5. Lesion involving cortex and medulla with sclerotic border may show soap bubble appearance due to endosteal nodding.
Pindborg's tumor is calcifying odontogenic epithelioma.

It produces typical‘driven snow” appearance on plain X-ray. Q


  • Bone lesions according to their predominant/primary site of occurrence/origin:
Epiphyseal Metaphyseal Diaphyseal
QChondroblastoma Chondromyxoid fibroma Fibrous dysplasia
QGiant cell tumor Osteochondroma Eosinophilic granuloma
Subchondral cyst Brodie’s abscess Metastasis
Solitary bone cyst Adamantinoma
Eosinophilic granuloma Osteosarcoma Leukemia, lymphoma
Chondrodysplasia punctata Chondrosarcoma Ewing sarcoma
Metastasis and myeloma after 40 years Non-ossifying fibroma Non-ossifying fibroma
QClear cell chondrosarcoma Osteomyelitis  
  • Everything About Bone Tumours
Nocturnal pain relieved by salicylates Osteoid osteoma
Nocturnal pain not relieved by salicylates Osteoblastoma
Trumpet shaped metaphysis
Coat hanger appearance
Diaphyseal aclasis
O ring sign
Punctate / Stippled calcification
Flicks / wispd of calcifications in a luscent area
a/w Olliers disease
a/w Maffucci syndrome
Celery stick appearance
Eccentric geographic lytic lesion
Dense punctate mottled calcification
Chickenwire mineralization
Codmans tumour
Codmans triangle
Sunray appearance
Bone tumour with calcified secondaries
Endosteal scalloping
Most common malignant bone tumour to appear benign radiologically
Dense popcorn / comma calcification
Eccentric epiphyseal lytic lesion with soap bubble appearance GCT
Physaliferous cells Chordoma
Homer Wright pseudorosettes
Onion skin lesions
Bone tumour resembling osteomyelitis
Ewings sarcoma
Double density sign Osteoid osteoma
Ballooned appearance
Fallen fragment sign
Unicameral bone cyst
Finger in balloon, Pencil in cup appearance ABC
Herrring tone arrangement of fibroblasts Fibrosarcoma
Benign bone condition with cellular atypia Chondromyxoid fibroma
Honeycomb appearance Adamatinoma
Pinwheel pattern
Storiform/whorled/radiating bundles
Non-ossifying fibroma, fibrous cortical defect
Shephard crooks deformity of femur
Ring of orange
Smoky matrix
Leontiosis ossea
Fibroud dysplasia
Coast of Maine appearance Polyostotic fibrous dysplasia / mccune albright syndrome
Driven snow appearance Pindborgs tumour
Sring sign Parosteal osteosarcoma
Target calcification Osseous lipoma
Polka dot sign
Corduroy / Accordion vertebra
Vertebral hemangioma
Geographic skull Eosinophilic granuloma
  1. Cervical spine trauma/injury
    Fractures limited to the vertebral body or posterior elements are considered stable; those involving both the vertebral body and posterior elements are considered unstable.
QOdontoid/ open mouth/ Modified water’s/ Dens view is the best x-ray view to detect fracture of odontois process, however whenever possible CT should be investigation of choice.
On a cervical spine radiograph, if you cannot visualize the lower cervical spine, obtain either a swimmer's view or CT.


Intervertebral disc is best visuliazed by MRI (not by CT).


One should be consistent in describing spinal degenerative disc disease. A disc bulge is a diffuse, symmetric extension of the disc beyond the end plate. A disc protrusion is a more focal extension of the disc in which the neck is wider than the more distal portion. A disc herniation is an extrusion of a portion of the disc in which the neck is the narrowest part. A disc sequestrum is a free disc fragment in the epidural space that has lost connection to the disc. 


Inflammatory and vascular disorders of the spinal cord may mimic neoplasms. 


Note: Tumors and other lesions within the spinal canal may be classified as extradural (outside the thecal sac), intradural-extramedullary (inside the thecal sac, but outside the cord), or intramedullary (inside the cord). Making this determination is the first step to selecting the correct differential diagnosis for a lesion.

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