SPOTS

Figure 46.111  High (Type II) dens fracture in frontal (A) and lateral (B) projections. The fracture lines (arrowheads) are confined entirely to the base of the dens.

Figure 46. 112 Low (Type III) dens fracture Figure 46.112  Low (Type III) dens fracture. (A) AP open-mouth view demonstrates lateral tilting of the dens. No fracture line is apparent. This is frequently the case in this type of fracture. (B) Lateral view demonstrates disruption of the ring of C2 (arrows). There is slight anterior tilting of the long axis of the dens. The dens is usually either in neutral or posterior angulation relative to the body of C2 in lateral projection. (C) A lateral tomogram clearly demonstrates the fracture line and the tilting of the dens.

Figure 46. 113 Extension teardrop fracture of C2 Figure 46.113  Extension teardrop fracture of C2. Note the triangular fragment arising from the anterior inferior margin of the vertebral body and the marked swelling in the retropharyngeal tissue representing a haematoma. The circular lucency within the soft tissues projected within the retropharyngeal soft tissues represents a snap on the cervical collar. There is slight posterior subluxation of C2 upon C3 in keeping with the hyperextension mechanism and disruption of the intervertebral disc.

Figure 46.114  Value of swimmer's projection in demonstration of the cervicothoracic junction. Initial lateral radiograph includes only the first five cervical vertebrae. There is a small fracture from the anterior inferior margin of C3. (B) A swimmer's projection clearly demonstrates dislocation at C7–T1 (arrows

Figure 46. 115 Flexion teardrop fracture Figure 46.115  Flexion teardrop fracture. (A) In the lateral radiograph of the cervical spine obtained immediately after the injury, the cervical spine is in the flexed attitude. A single large fragment consisting of the anteroinferior corner of the body of C5 is present. The fifth vertebral body is posteriorly displaced and, in addition, widening of the interfacetal and interspinous spaces between C5 and C6 indicates complete disruption of the posterior ligament complex and bilateral interfacetal dislocation. (B) In the lateral examination carried out 2 weeks after the injury, the characteristic teardrop-shaped fragment is seen. In addition, the subjacent intervertebral disc space is abnormally widened, as are the interfacetal and interspinous spaces, indicating complete soft tissue disruption at the involved level.

Figure 46.116  Bilateral locked facets at C4–5 (interfacetal dislocation). Note that the lateral mass of the inferior facet of C4 is locked anteriorly to the superior facet of C5.

Figure 46. 117 Unilateral locked facets Figure 46.117  Unilateral locked facets. In the frontal projection (A), the spinous processes from C6 and above (arrowheads) are rotated off the midline. In the lateral projection (B), the sixth cervical vertebra is displaced slightly anteriorly on C7 by a distance less than half the anteroposterior diameter of a cervical vertebral body. Additionally, from the level of C6 upwards, the posterior cortical margins of the articular masses (arrowheads) are not superimposed, reflecting the rotational components of this injury.

Figure 46. 118 Unilateral locked facets at C5–6 Figure 46.118  Unilateral locked facets at C5–6. In this case the ‘bow tie’ or ‘butterfly’ configuration of the facet is characteristic of this lesion and is clearly depicted by the dashed lines. Note that at the level of dislocation, the vertebrae above are in the oblique projection and those below are in the lateral projection. The distance between the posterior surface of the facets and the spinolaminar line above the level of dislocation is obliterated, whereas the space is preserved below the level of dislocation. This is a very sensitive indicator that the vertebrae above are rotated and those below are in the lateral projection. One can see that the inferior facet of one side (arrow) lies anterior to the vertebra below.

Figure 46. 119 Unilateral locked facets of C6 on the left. CT images Figure 46.119  Unilateral locked facets of C6 on the left. CT images. The facet joints at C5/C6 are subluxed on the right side (A). The midline images (B) show that C5 is subluxed anteriorly upon C6 approximately 25% of the width of vertebral body. The C5 facet is locked anterior to C6 facet on the left side (C).

Figure 46. 120 Hyperextension fracture-dislocation of C4 Figure 46.120  Hyperextension fracture-dislocation of C4. The frontal projection (A) shows a comminuted fracture of the articular mass of C4 on the right (*). The lateral projection (B) shows that the body of C4 is anteriorly displaced. The anatomy of the posterior elements at the C4–5 level is completely disorganized. In the right anterior oblique projection (C) the articular mass of C4 is shown to be severely comminuted. The inferior articulating facet of C4 has been completely destroyed (‘flattened facet’ sign). In addition, there is a transverse fracture through the superior articulating facet of C5 (arrowhead). In the left anterior oblique projection (D) there is an interfacetal dislocation of C4 with respect to C5 (stemmed arrow).

Figure 46. 121 Anterior subluxation of C3 on C4 Figure 46.121  Anterior subluxation of C3 on C4. In the flexed position (A), C3 is anteriorly displaced with respect to C4 by a distance of 2–3 mm. In addition C3 has pivoted upon the anteroinferior corner of its vertebral body, and this, coupled with the anterior translation, has caused a hyperkyphotic angulation at the C2–3 level. The interfacetal joint space is widened posteriorly and the interspinous space is widened (‘fanning’). In the same patient, in the hyperextended position (B) the spine appears normal.

Figure 46. 123 Fractures of the posterior elements Figure 46.123  Fractures of the posterior elements. (A) Clay shoveller's fracture (arrow) of the spinous process of C6–7. (B,C) Left pediculolaminar fracture. The plain radiographs were unremarkable. The arrow indicates the fracture of the pedicle and transverse process. The laminar fracture is identified by arrowheads.

Figure 46. 126 Schmorl's nodes and limbus vertebra Figure 46.126  Schmorl's nodes and limbus vertebra. Note the sharply defined dome-like-densities arising from the end-plate in these two adjacent vertebrae (A). (B) Limbus vertebra. There is a well-marginated ossicle at the anterior superior margin of the vertebral body. Note that the underlying vertebral body margin is also well defined. This represents a developmental defect, presumably of the ring apophysis.

Figure 46. 127 Fracture-dislocation of T11–12 Figure 46.127  Fracture-dislocation of T11–12. The AP projection (A) shows very few findings. Closer examination reveals a wide separation of the spinous processes of T11–12 (arrows) and obliteration of the T12–L1 vertebral disc space. There is also a fracture from the anterior superior margin of the 12th vertebral body on the right. (B) A dislocation is demonstrated, with displacement of a small fragment of bone from the anterior superior margin of the vertebra below the level of dislocation (arrow). The fractures of the posterior elements are not well visualized due to overlying ribs. There is characteristic wedging of the vertebral body below the level of dislocation.

Figure 46. 129 Burst fracture of L3 Figure 46.129  Burst fracture of L3. (A) Lateral projection demonstrates slight anterior wedging with obvious compression of the vertebra. Note the retropulsion of the fragment rising from the superior margin of the vertebra (*). This fragment is displaced into the spinal canal and may result in neurological injury. (B) AP projection demonstrates compression of the vertebra. Note the widening of the interpediculate distance (arrows), indicating presence of a sagittal fracture in the vertebra and posterior elements, allowing lateral displacement. These findings are characteristic of a burst fracture.

Figure 46. 131 Chance fracture of L1 Figure 46.131  Chance fracture of L1. The frontal projection (A) shows a comminuted fracture of the left transverse process (*), transverse fracture of the left pedicle (arrowhead), separation of the T12 and L1 laminae and spinous processes (double arrow) and a fracture of the right superolateral cortex of L1 (curved arrow). In the lateral projection (B) the arrowheads indicate a distracted transverse fracture of the spinous process and laminae and the arrows indicate the horizontal fracture of the body with anterior wedging.

Different pts Figure 47.1  Patterns of bone destruction. (A) AP radiograph of the distal radius in a patient with non-ossifying fibroma (NOF), demonstrating the sharp, ‘geographic’ margin indicating slow growth. Endosteal scalloping and bone expansion with an intact overlying cortex are additional features of slow growth. (B) AP radiograph of the humerus showing a ‘moth-eaten’ appearance caused by the coalescence of multiple small lytic areas in a patient with renal carcinoma metastasis. (C) AP radiograph of the distal femur showing a ‘permeative’ pattern of bone destruction in a patient with primary bone lymphoma. (D) AP radiograph of the fibula showing a lytic lesion with expansion and destruction of the cortex indicating an aggressive growth pattern.

Figure 47. 2 Patterns of periosteal reaction Figure 47.2  Patterns of periosteal reaction. (A) Lateral radiograph of the tibia showing a solid periosteal reaction due to osteoid osteoma. (B) AP radiograph of the distal tibia showing a single, laminated periosteal reaction associated with a Brodie's abscess. (C) AP radiograph of the humerus showing a multilaminated periosteal reaction associated with Ewing's sarcoma. (D) AP radiograph of the proximal ulna showing a ‘hair-on-end’ type vertical periosteal reaction associated with Ewing's sarcoma. Note also the Codman's triangle (arrow). Different pts

Different pts Figure 47.3  Patterns of matrix mineralization. (A) AP radiograph of the proximal humerus in a patient with metachondromatosis, showing typical chondroid calcification. (B) AP radiograph of the proximal fibula in a patient with osteosarcoma showing typical osseous mineralization. (C) AP radiograph of the proximal femur in a patient with fibrous dysplasia showing typical ground-glass mineralization. (D) AP radiograph of the distal femur in a patient with malignant fibrous histiocytoma complicating a heavily calcified medullary bone infarct.

Figure 47. 4 Role of CT in lesion characterization Figure 47.4  Role of CT in lesion characterization. (A) CT through the left acetabulum showing radiographically occult chondroid matrix mineralization in a patient with grade 1 chondrosarcoma. (B) CT through the tibia showing the nidus of an osteoid osteoma Different pts

Figure 47. 5 Role of MRI in local staging Figure 47.5  Role of MRI in local staging. (A) Coronal T1-weighted spin-echo MRI in a patient with distal femoral osteosarcoma showing the intraosseous tumour extent represented by intermediate signal intensity (SI) contrasting against the hyperintense fatty marrow. (B) Coronal T1-weighted spin-echo MRI in a patient with distal femoral osteosarcoma showing a ‘skip’ metastasis (arrow). (C) Axial T2-weighted fast spin-echo MRI in a patient with distal femoral osteosarcoma showing extraosseous tumour abutting the neurovascular bundle (arrow). (D) Axial fat suppressed T2-weighted fast spin-echo MRI through the distal femur in a patient with osteosarcoma showing joint involvement (arrow).

Figure 47. 6 Proximal phalangeal enchondroma Figure 47.6  Proximal phalangeal enchondroma. AP radiograph of the index finger showing a pathological fracture.

Sagittal T2*-weighted gradient-echo MR image Figure 47.7  Distal femoral chondroma. Sagittal T2*-weighted gradient-echo MR image showing classical appearances of a chondroma. Calcification is manifest as focal areas of signal void. Sagittal T2*-weighted gradient-echo MR image

Figure 47. 8 Periosteal chondroma Figure 47.8  Periosteal chondroma. (A) Lateral radiograph of the distal femur showing a calcified surface lesion. (B) Axial fat-suppressed T2-weighted fast spin-echo MRI showing a hyperintense lobulated lesion, without medullary infiltration.

Figure 47. 9 Enchondromatosis Figure 47.9  Enchondromatosis. AP radiograph of the distal femur and tibia showing multiple enchondromas and distal femoral deformity consistent with Ollier's disease.

Figure 47.13  BPOP. AP radiograph of the little finger showing a bizarre parosteal osteochondromatous proliferation adjacent to the middle phalanx. This rare lesion is a tumour-like disorder, which is included here for reasons of differential diagnosis. It arises adjacent to the cortex of the small tubular bones of the hands or feet and may resemble an osteochondroma. However, continuity between the lesion and underlying bone is not found

Figure 47. 14 Chondroblastoma in the immature and mature skeleton Figure 47.14  Chondroblastoma in the immature and mature skeleton. (A) AP radiograph of the knee showing a lobulated, lytic lesion (arrow) adjacent to the open growth plate and limited to the epiphysis. (B) AP radiograph of the hip showing extension of the lesion across the fused growth plate.

Coronal fat-suppressed T2-weighted fast spin-echo MRI Figure 47.15  Chondroblastoma of the left femoral head. Coronal fat-suppressed T2-weighted fast spin-echo MRI showing the hypointense lesion with surrounding marrow oedema and reactive joint effusion. Coronal fat-suppressed T2-weighted fast spin-echo MRI

Figure 47. 16 Chondromyxoid fibroma Figure 47.16  Chondromyxoid fibroma. Lateral radiograph of the proximal tibia showing expansion of the anterior cortex

Figure 47. 17 Giant bone island Figure 47.17  Giant bone island. AP radiograph of the left hip showing a uniformly sclerotic bone island (arrow) in the supra-acetabular region of the ilium.

Figure 47. 18 Osteoid osteoma Figure 47.18  Osteoid osteoma. AP radiograph of the tibia shows solid thickening of the anterolateral tibial cortex containing a small nidus (arrows).

(A) Coronal fat-suppressed T2-weighted fast spin-echo MRI . (B) Axial T2*-weighted gradient-echo MRI Figure 47.21  Osteoid osteoma. AP radiograph of the hip showing an intra-articular osteoid osteoma involving the medial femoral neck (arrow). MRI features. (A) Coronal fat-suppressed T2-weighted fast spin-echo MRI shows a hypointense nidus (arrow) with adjacent reactive soft tissue and medullary oedema. (B) Axial T2*-weighted gradient-echo MRI shows the nidus in a medial subperiosteal location (arrow).

Figure 47. 24 Osteoblastoma of the proximal ulna Figure 47.24  Osteoblastoma of the proximal ulna. Lateral radiograph shows a calcified, expanded lytic lesion (arrow) with surrounding reactive medullary sclerosis. Axial STIR MRI showing fluid levels indicative of secondary aneurysmal bone cyst change. Note also extensive reactive soft tissue oedema. Axial STIR MRI

Axial T2-weighted fast spin-echo MRI Figure 47.26  Simple bone cyst. AP radiograph of the left arm showing a fractured proximal humeral simple bone cyst with a ‘fallen fragment’ (arrow). Axial T2-weighted fast spin-echo MRI shows fluid levels indicative of previous fracture

Figure 47.28  AP radiograph showing an aneurysmal bone cyst of the proximal tibial metaphysis. CT showing a proximal tibial aneurysmal bone cyst with evidence of faint septal ossification (arrowheads).

Figure 47.30  AP radiograph of the forearm showing a subperiosteal aneurysmal bone cyst of the radius.

Figure 47.31  Axial T2-weighted fast spin-echo MRI showing multiple fluid levels in a proximal tibial aneurysmal bone cyst.

Figure 47. 33 CT of the sacrum showing a giant cell tumour Figure 47.33  CT of the sacrum showing a giant cell tumour. Note the extension to the left sacroiliac joint.

Coronal T2-weighted fast spin-echo MRI Figure 47.34  Coronal T2-weighted fast spin-echo MRI showing a distal femoral giant cell tumour with predominantly low SI due to haemosiderin deposition from chronic haemorrhage. Coronal T2-weighted fast spin-echo MRI

Figure 47.35  AP radiograph of the proximal tibia showing a diaphyseal fibrous cortical defect. Note the ground-glass appearance of the matrix.