*In 1947, Gissane described his critical angle or crucial angle.
*He noted a distinct angular cortical platform that parallels the lateral process of the talus on lateral radiographic projection.
*This cortical density represents the dense subchondral bone lying beneath the posterior, anterior and middle facets.
*The angular measurements vary from 130 to 145 degrees, with an average of 130 degrees.
*During an axial impaction load, the lateral process of the talus is driven through the posterior facet in a wedge like manner that facilitates the primary fracture. This extends from the lateral cortical vertex of the crucial angle and exits plantarly through the neutral triangle.
*The initial fracture, as described by Essex Lopresti, is located on the anterior distal lip of the posterior facet and connects to the primary fracture line. This fracture extends through the facet, splits it into one or multiple fragments, and impacts the lateral portions into the body.
*The crucial angle reveals the angular relationship of the calcaneal facets and should appear identical when taken bilaterally.
*Unlike Bohler’s angle, which may be aberrant with displaced extraarticular and intraarticular fractures, the crucial angle is more specific for intraarticular distortion.
*In the above second figure: Lateral radiograph of the calcaneus shows compression (light blue arrows) and traction (yellow arrows) trabeculae, with the neutral triangle (brown triangle) in between with sparse trabeculae. The thickened cortical or thalamic portion of the bone supporting the articular facets is shown (T). The critical angle of Gissane (G) and the Boehler angle (B) have also been drawn in. The Boehler angle is normally 20°–40°.
*The above picture shows the MILWAUKEE brace, which is named after the city of Milwaukee where it was designed.
*It is most more acceptable than other braces.
*This is a body cast with a turn-buckle in between. The tightening of the turn-buckle stretches the concave side of the curve, thus correcting the deformity.
*Another type of cast called THE LOCALISER CAST is used for scoliosis. This is a body cast applied with the spine in traction. A special localiser table is required for this. I could not find a picture for this.
*Cobb's angle, a measurement used for evaluation of curves in scoliosis on an AP radiographic projection of the spine (Fig.1).
*When assessing a curve the apical vertebra is first identified; this is the most likely displaced and rotated vertebra with the least tilted end plate. The end/transitional vertebra are then identified through the curve above and below. The end vertebra are the most superior and inferior vertebra which are least displaced and rotated and have the maximally tilted end plate.
*A line is drawn along the superior end plate of the superior end vertebra and a second line drawn along the inferior end plate of the inferior end vertebra.
*If the end plates are indistinct the line may be drawn through the pedicles. The angle between these two lines (or lines drawn perpendicular to them) is measured as the Cobb angle.
*In S-shaped scoliosis where there are two contiguous curves the lower end vertebra of the upper curve will represent the upper end vertebra of the lower curve. Because the Cobb angle reflects curvature only in a single plane and fails to account for vertebral rotation it may not accurately demonstrate the severity of three dimensional spinal deformity.
*As a general rule a Cobb angle of 10 is regarded as a minimum angulation to define scoliosis.
*Scoliosis is the sideways curvature of the spine.
*It is classified into two major types. They are Non-structural (transient) and Structural (permanent) types of scoliosis
*Non-structural scoliosis is again divided into POSTURAL scoliosis, COMPENSATORY and SCIATIC scoliosis.
*Structural scoliosis is divided into IDIOPATHIC, CONGENITAL and PARALYTIC scoliosis.
*Overall POSTURAL scloliosis is the most common type of scoliosis.
*IDIOPATHIC scoliosis is the most common type of permanent scoliosis.
*CONGENITAL SCOLIOSIS :
- This type is always associated with some form of radiologically demonstrable anomaly of the vertebral bodies. These are
A. HEMIVERTEBRAE - Only One half of the vertebra grows
B. BLOCK VERTEBRAE :- Two vertebral bodies are fused.
C. UNSEGMENTED BAR : - A bar of bone joining two adjacent vertebrae on one side, thereby preventing growth on that side.
*Shown below are the Plain radiographs of a pediatric patient with congenital scoliosis. (A) Posterior--anterior and (B) lateral views of the spine, with multiple congenital vertebral anomalies including hemivertebrae at thoracic and lumbar spine and block vertebrae at lumbar spine.
1q: Which is the commonest site of spinal injuries ?
a. Thoraco-lumbar segment
b. Lower cervical spine
c. Upper cervical spine
d. Sacral spine
2q: All of the following are true about spinal injuries except ?
a. About 80% of spinal injuries result in neurological deficit
b. Thoracolumbar spine injury may result in paraplegia
c. Cervical spine injury may result in Quadriplegia
d. Any lesion to the spinal cord above T5 causes hypotension
3q: Number of vertebrae in human body ?
a. 33
b. 34
c. 35
d. 36
4q: What are the number of Cervical,thoracic,lumbar,sacral and coccygeal vertebrae in the human body respectively?
a. 7,12,5,5,4
b. 8,12,5,5,4
c, 7,12,5,5,5
d. 8,12,5,5,5
5q: The nucleus pulposus is a remnant of ?
a. Sclerotomes
b. occipital myotomes
c. Notochord
d. Mesenchyme
6q: The entire vertebral column has similar articulation except
a. C1-C2
b. C7-T1
c. T12-L1
d. L5-S1
7q: The neural arches of adjacent vertebrae articulate through which joints
a. Facet joints
b. Ball in socket joints
c. Both
d. None
8q: The adjacent laminae of the vertebrae are joined together by ?
a. Ligamentum teres
b. Ligamentum flavum
c. Ligament of treitz
d. Anterior longitudinal ligaments
9q: Posterior ligament complex includes all of the following except
a. Ligamentum flavum which joins the adjacent laminae
b. Interspinous ligaments which connect the adjacent spinous processes
c. Supraspinous ligament which connects the tips of spinous processes
d. Inter-transverse ligaments which connect the adjacent transverse processes
e. Posterior longitudinal ligament which connects the vertebral bodies posteriorly
10q: Assertion: Pure dislocation (without associated fracture) does not occur in the lumbar spine. Reason: The facets of the lumbar spine are stout and vertically placed where as cervical spine facets are short and more horizontally placed.
a. Assertion is True but Reasoning is false
b. Assertion is false but Reasoning is true
c. Both are true
d. Both are false
11q: The 'Three-Column concept' divides the vertebra into which of these columns
a. Medial,middle and lateral columns
b. Anterior,middle and Posterior columns
c. Both
d. None
12q: Which of the following is True about the 'Three column concept' of the spine ?
a. The anterior column consists of the anterior longitudinal ligament and the anterior part of annulus fibrosis along with the anterior half of the vertebral body
b. The middle column consists of the posterior longitudinal ligament and the posterior part of the annulus fibrosis along with the posterior half of the vertebral body
c. The posterior column consists of the posterior bony arches along with the posterior ligament complex
d. All the above
13q: Which of the following is falsely matched (multiple answers)
a. Wedge compression fracture of the vertebra-One column disrupted-Stable spine
b. Wedge compression fracture of the vertebra-One column disrupted-Unstable spine
c. Burst fracture of the body of vertebra-Two columns disrupted-Unstable spine
d. Burst fracture of the body of vertebra-Three columns disrupted-Unstable spine
e. Dislocation of one vertebra over the other-Three columns disrupted-Unstable spine
14q: Spinal injuries are best classified on the basis of mechanism of injury into the following types :
1.Flexion injury
2. Flexion-rotation injury
3. Flexion distraction injury
4. Extension injury
5. Direct injury
6. Indirect injury due to violent muscle contraction
7. Vertical compression injury
- Of the above which is the most common type of spinal injury ?
15q:Spinal injuries are best classified on the basis of mechanism of injury into the following types :
1.Flexion injury
2. Flexion-rotation injury
3. Flexion distraction injury
4. Extension injury
5. Direct injury
6. Indirect injury due to violent muscle contraction
7. Vertical compression injury
- Of the above which is the worst type of spinal injury which leaves a highly unstable spine and has a high incidence of neurological damage ?
16q: In a Flexion injury of the spine, Compression fracture of which of the following cervical vertebrae is common ?
a. C1-C2
b. C3-C4
c. C5-C7
d. None
17q: In a Flexion injury of the spine, Dislocation of one vertebrae over another is common in which part of the cervical spine?
a. C1 over C2
b. C3 over C4
c. C5 over C6
d. C6 over C7
18q: Which of the following is false about the Dorso-lumbar spine involvement in the flexion injury of the spine
a. Wedge compression of the L1 is most common type of injury
b. Wedge compression of L2 is the second most common type of injury
c. Wedge compression of the T12 is the third most common type of injury
d. It is a stable injury if compression of the vertebra is more than 50 percent of its posterior height
19q: Which of the following is most commonly associated with burst fracture of spine ?
a. Flexion injury
b. Flexion-rotation injury
c. Vertical compression injury
d. Extension injury
20q: Extension injury is most commonly seen in :
a. Cervical spine
b. Thoracic spine
c. Lumbar spine
d. Any of the above
This injury results in chip fracture of the anterior rim of a vertebra. Forehead striking against the windscreen forcing the neck into hyperextension and shallow water diving .
21q: Which of the following type of spinal injury occurs most commonly due to seat belt while driving a car?
a. Flexion injury
b. Flexion-rotation injury
c. Extension injury
d. Flexion-distraction injury
22q: 'Chance fracture' is associated with which of the following type of spine injury ?
a. Flexion injury
b. Flexion-rotation injury
c. Extension injury
d. Flexion-distraction injury
*With the sudden stopping of a car, the upper part of the body is forced forward by inertia while the lower part is tied to the seat by the seat belt. The flexion force thus generated has a component of 'distraction' with it.It commonly results in a horizontal fracture extended into the posterior elements and involving a part of the body. It is termed a 'Chance fracture'. It is an unstable injury.
23q: Which of the following type of spinal injury is associated with huge retroperitoneal hematoma ?
a. Direct injury
b. Flexion injury
c. Flexion-distraction injury
d. Violent muscle contraction
*Violent muscle contraction is a rare spinal injury, where sudden violent contraction of the psoas results in fractures of the transverse processes of multiple lumbar vertebrae. It may be assocaited with a huge retroperitoneal hematoma.
24q: Antero-posterior bending and sideways bending of the spine is called ________ and ________ respectively
a. Kyphosis and scoliosis
b. Scoliosis and kyphosis
c. kyphosis and lordosis
d. Lordosis and kyphosis
25q: In which of the following types of spinal injury, the plain X-ray appears normal in the presence of highly unstable spinal injury?
a. Fall from height on the buttocks
b. Strong hit on the shoulder
c. Whiplash injury to the cervical spine
d. Bullet injury to the spine
*In the whiplash injury to the cervical spine, all the three columns of the spine are disrupted in a sudden hyperflexion followed by sudden hyperextension of the neck. eg: after the sudden stopping of car.
26q: All of the following regarding the diagnosis of spinal injuries are true except
a. A tomogram helps in better delineation of a doubtful area
b. Myelogram has proved to be a very helpful investigation in acute spinal injuries
c. One can see damaged structures more clearly with CT scan
d. MRI is the best modality of imaging in an injured spine
27q: CT is of no help in which of the following type of injury ?
a. Vertical compression injury
b. Extension injury
c. Direct injury
d. Flexion rotation injury
*Caused by motor vehicle accident and shallow water diving leading to avulsion fracture of anterior lip of vertebra. C5-C6 and lumbar spine most commonly involved. There is only anterior column failure and it is a stable fracture.
28q: What is the name of the skull calipers used for skull traction for the reduction of Cervical spine fractures?
a. Crutchfield tongs traction
b. Hutchinson's tongs traction
c. Trendelenburg tongs traction
d. Gopalan's tongs traction
29q: All of the following are true about Wedge compression fracture of the vertebra except ?
a. Results from extension force
b. Posterior elements are usually intact
c. Stable injury
d. Reduction is not required in management
e. Neck is kept immobilized with the help of skull traction
f. Neck is supported by cervical collar, plaster of paris cast or brace once the pain and muscle spasm subsides
g. Exercises of the neck are started after 8-12 weeks
30q: All of the following are true about Jefferson's fracture except :
a. It is a burst fracture of atlas where both anterior and posterior arches of the atlas are fractured by a vertical force acting through the skull
b. Displacement is very severe
c. More often than not the spinal cord escapes injury
d. Treatment consists of traction, followed by immobilisation in Minerva jacket or halo-pelvic support
31q: Which of the following statement is true regarding atlanto-axial fracture dislocation?
a. A fracture-dislocation of the atlanto-axial joint is more common than pure dislocation
b. A pure dislocation is more often associated with a neurological deficit
c. The displacement is commonly posterior
d. Treatment consists of skull, traction followed by immobilisation in Minerva jacket
32q: Clay shoveller's fracture is a fracture of the spinous process of which vertebra?
a. C1
b. T1
c. L1
d. C2
33q: All of the following operative methods are performed whenever necessary in Thoracic and lumbar spine injuries except
a. Harrington instrumentation - bilateral
b. Luque instrumentation
c. Hartshill rectangle fixation
d. Pedicle screw fixation
e. Hongkong operation
34q: SOMI brace is used for
a. Cervical spine injuries
b. Thoracic spine injuries
c. Lumbar spine injuries
d. all
*SOMI stands for Sternal Occipital Mandibular Immobilizer, shown below.
35q: ASH brace is used for
a. Dorsolumbar spine injury
b. Cervical spine injury
c. Both
d. None
*ASH stands for Anterior-superior hyperextension brace, shown below.
*Primary tumors that may present as pulsating lesions :
- Telengiectatic Osteogenic sarcoma
- Angioendothelioma/Angiosarcoma of bone
- Aneurysmal bone cyst
- Giant cell tumor (rarely)
*Secondaries/Metastases that may present as pulsating lesions :
- Metastasis from Renal cell carcinoma
- Metastasis from Thyroid carcinoma
*Causes of Osteolytic metastasis :
- Kidney (expansile) and Thyroid : Expansile lytic osseous metastasis are characteristic of Renal cell carcinoma (kidney) and Thyroid .
- Lung
- Gastrointestinal tract (GIT)
- Breast (occasionally)
- Less commonly melanoma, carcinoma of bronchus and pheochromocytoma may also present with Expansile lytic lesions.
*Causes of Osteoblastic metastasis :
- Prostate - Breast (may be mixed) - Seminoma - Carcinoid - Neurogenic tumors - Uterus - Ovary
*Pseudoarthrosis is a false joint, that may develop after a fracture that has not united properly.
*It may be idiopathic.
*Causes of Pseudoarthrosis (in decreasing order of frequency are) :
1. Non union of a fracture - including pathological fracture.
2. Congenital - in the middle to lower third of the tibia with or without fibula. 50% present in the first year. Later there may be cupping of the proximal bone and pointing of the distal bone end.
3. Neurofibromatosis - seen in 50% of patients with pseudoarthrosis.
4. Osteogenesis imperfecta
5. Cleidocranial dysplasia - congenitally in the femur
6. Fibrous dysplasia
7. Ankylosing spondylitis - in the fused bamboo spine .
*When a child presents with fracture neck of femur which is less than 3 weeks old, then the fracture is managed by CLOSED REDUCTION and INTERNAL FIXATION with Austin Moore pins and Knowle's pins.
*Austin Moore pin and Knowle's pin shown in the picture above.
*X-ray of a case of Fracture neck of femur, fitted with Austin Moore pins.
*Illustration showing the Knowle's pins used in the management of fracture neck of femur.
*X-ray of a case of fracture neck of femur managed by knowle's pins.
*When an adult whose age is less than 60 years presents with a fracture neck of femur, less than 3 weeks old, then the fracture is managed by Closed/open reduction and internal fixation by MULTIPLE CANNULATED CANCELLOUS SCREWS (shown in the picture above)
*When an adult whose age is more than 60 years presents with fracture of neck of femur, less than 3 weeks old, then the next step is to assess his hip and take a decision. If there is preexisting arthritis in the patient, then Total Hip Replacement is the treatment of choice. - But if the hip is otherwise normal, then Hemireplacement arthroplasty is done. A.M.Prosthesis is one of several prostheses used in Hemireplacement arthroplasty.
*A bumper fracture is a compression fracture of the lateral tibial condyle due to a forceful valgus stress applied to the knee.
*The name is derived from the fact that a car bumper hitting the lateral aspect of the knee when the leg is firmly planted on the ground is one of the most common causes of this type of injury.
*If the medial collateral ligament remains intact, the lateral femoral condyle is forced down on the lateral tibial condyle and this causes a compression fracture.
*Older patients with osteoporosis are the most prone to this type of injury. There may be a hemarthrosis, and the lateral tibial plateau will be tender.
*Compression fracture of the lateral tibial plateua, resulting in separation at the margin of the plateau or depression of the central portion of the artucular surface.
*A valgus injury of the knee may result in a fracture of the lateral tibial plateau. At times these fractures are difficult to identify and are obvious only on oblique radiographs.
*The fractures consist of either a vertical split through or a depression of a portion of the joint surface. There may be an associated fracture of the neck of the fibula.
*When the fracture involves the lateral margin of the plateau or is associated with a fracture of the fibula, an accompanying disruption of the medial collateral ligament is likely.
*Treatment: Stabilisation and fixation where required.
BASIC PHYSIOLOGY OF NORMAL BONE RESORPTION AND FORMATION :
*Osteoclast maturation is regulated by various factors, such as Receptor Activator of Nuclear Factor-kappaB (NF-kappaB) Ligand (RANKL). RANKL can exist as a soluble form and binds to the osteoclast receptor RANK.
*This binding activates osteoclast differentiation via the translocation of NF-kappaB into the nucleus by intermediates such as Tumor Necrosis Factor (TNF) Receptor-Associated Factor 6 (TRAF6).
*RANKL signals can be blocked by a soluble RANKL-binding decoy receptor, osteoprotegerin (OPG), produced by osteoblasts.
*Vacuolar H+-ATPase pump (H+), matrix metalloproteinase (MMP), Cathepsin K and Tartrate-Resistant Acid Phosphatase (TRAcP) are involved in osteoclast activity.
*This picture above helps us in understanding the pathophysiology behind PAGET'S disease :
*PATHOPHYSIOLOGY OF PAGET'S DISEASE:
- The principal abnormality in Paget disease is the increased number and activity of osteoclasts.
- Pagetic osteoclasts are large, increased 10- to 100-fold in number, and have a greater number of nuclei (as many as 100 compared to 3–5 nuclei in the normal osteoclast).
- The overactive osteoclasts may create a sevenfold increase in resorptive surfaces and an erosion rate of 9 microg/d (normal is 1 microg/d).
- Several causes for the increased number and activity of pagetic osteoclasts have been identified:
(1) Osteoclastic precursors are hypersensitive to 1,25(OH)2D3;
(2) Osteoclasts are hyperresponsive to RANK ligand (RANKL), the osteoclast stimulatory factor that mediates the effects of most osteotropic factors on osteoclast formation;
(3) Marrow stromal cells from pagetic lesions have increased RANKL expression;
(4) Osteoclast precursor recruitment is increased by interleukin (IL) 6, which is increased in the blood of patients with active Paget disease and is overexpressed in pagetic osteoclasts;
(5) Expression of the proto-oncogene c-fos, which increases osteoclastic activity, is increased; and
(6) The antiapoptotic oncogene Bcl-2 in pagetic bone is overexpressed. Numerous osteoblasts are recruited to active resorption sites and produce large amounts of new bone matrix. As a result, bone turnover is high and bone mass is normal or increased, not reduced.
- The characteristic feature of Paget disease is increased bone resorption accompanied by accelerated bone formation.
- An initial osteolytic phase involves prominent bone resorption and marked hypervascularization.
- Radiographically, this manifests as an advancing lytic wedge, or "blade of grass" lesion.
- The second phase is a period of very active bone formation and resorption that replaces normal lamellar bone with haphazard (woven) bone.
- The mosaic pattern of woven bone is structurally inferior and can bow and fracture more readily.
- At the same time, fibrous connective tissue may replace normal bone marrow.
- In the final sclerotic phase, bone resorption declines progressively and leads to a hard, dense, less vascular pagetic or mosaic bone, which represents the so-called burned-out phase of Paget disease.
- All three phases may be present at the same time at different skeletal sites.
*Acutely marginated bone demineralization during lytic phase in skull - OSTEOPOROSIS CIRCUMSCRIPTA.
*Acutely marginated demineralization of long bones - BLADE OF GRASS SIGN and FLAME SHAPED MARGIN.
*Mixed lytic and sclerotic phase in spine - PICTURE FRAME VERTEBRAE
*Mixed lytic and sclerotic phase in skull - COTTON WOOL SKULL.
