1. Imaging of spinal trauma
Dr. Vishal Sankpal

2. Imaging modalities
Radiography
Computed Tomography (CT)
MRI

3. The three-view radiography series
antero-posterior,
lateral, and
open mouth odontoid
is still the imaging modality of choice as initial study for symptomatic patients
( as recommended by the American College of Radiology Appropriateness Criteria and the Advanced Trauma Life Support (ATLS) course of the American College of Surgeons )

4. Special consideration regarding radiation dose due to the inherent radio-sensitivity of developing tissues in children compared to adults
Antero-posterior (AP) and lateral radiographs under the age of 4
AP, lateral and open mouth radiographs from 4 to 8 years old
Children at 9 years of age and older are imaged with the adult protocol. This is the approximate age at which the fracture patterns revert to the adult patterns.
CT is reserved for those subjects in whom an abnormality is identified on radiography.

5. Plain Film Radiography and CT of the Cervical Spine: Normal Anatomy

6. Flexion-extension radiographs are not very helpful in the acute setting because muscle spasm in acutely injured patients precludes an adequate examination
Flexion-extension radiographs are helpful for ensuring that minor degrees of anterolisthesis or retrolisthesis in patients with cervical spondylosis are fixed deformities

8. 1 – Anterior spinal line
2 – Posterior spinal line
3 – Spino-laminar line

9. Spinolaminar line –
Any displacement in this line may be an indication of subtle traumatic vertebral injury/dislocation.
A line drawn through C1- 3 spinolaminar lines should intercept the C2 spinolaminar line.
A displacement of the C2 spinolaminar line of more than 2 mm, compared with a line drawn between the spinolaminar lines of C1 and C3, is abnormal.

10. Basion dental interval (BDI) -
the basion (white dot) should lie within 12 mm of the top of the odontoid process
The basion-axial interval (BAI) -
the PAL (white line) should lie within 12 mm of the basion

11. Basion dental interval
The basion-axial interval
Normal < 12 mm

12. Concept initially evolved from a retrospective review of thoracolumbar spine injuries and observation of spinal instability, it has also been applied to the cervical spine.
The posterior column consists posterior ligamentous complex.
The middle column includes the posterior longitudinal ligament, posterior annulus fibrosus, and posterior wall of the vertebral body.
The anterior column consists of the anterior vertebral body, anterior annulus fibrosus, and anterior longitudinal ligament.
Three-column concept of the spine
(Denis)

13. Anterior Atlanto-dental interval (AADI)
does not normally exceed 3 mm in adults and 5 mm in children
In adults, because of maturity of the transverse atlantal ligament, the AADI remains constant in flexion and extension.
In infants and children until the age of approximately 8 years, the AADI varies in width in flexion and extension.

14. Diameter of the spinal canal
Difficulties in making accurate measurements secondary to differences in magnification or focal spot-film distance.
This problem can be overcome by comparing the AP width of the canal with that of the vertebral body (canal / body)
The normal ratio of the spinal canal (white arrow) to the vertebral body (black arrow) is 0.8 or more.

15. The normal atlanto-axial articulation in open- mouth odontoid view
The lateral margins of the lateral atlanto-axial joints are symmetric and are on essentially in the same vertical plane, plus or minus 1 mm.

17. Cervical spine injuries - classification
Location -
Upper cervical injuries - include injuries to the base of the skull (including the occipital condyles or C0), C1, and C2.
Lower cervical injuries (sub-axial) - include injuries from C3 through C7

18. Cervical spine injuries - classification
Vector forces –
Flexion
Flexion-rotation
Lateral flexion
Extension
Extension-rotation
Vertical compression

19. Stability versus Instability
When assessing stability in the spinal column, the three-column theory of Denis suggests that if two columns have failed, the spinal column is unstable.

20. Occipital condyle fractures
OCF are rare, being found at postmortem examination in 1% to 5% of patients who had sustained trauma to the cervical spine and head
Clinical manifestations of OCF are highly variable
Not typically shown with conventional radiography

21. Plain film findings:
Difficult diagnosis due to overlapping of the bony structures of the face, upper cervical spine, and skull base.
May be visible in open-mouth views that include the condyles
OCF are readily identified on axial or coronal reformatted CT

22. Anderson-Montesano classification system (for OCF):
▪ Type I: Loading fracture of the occipital condyle, typically comminuted and in a vertical sagittal plane, but where there is no fracture displacement or associated craniocervical instability.
▪ Type II: Skull-base fracture that propagates into one or both occipital condyles
▪ Type III: Infero-medial avulsion fracture of the condyle by the intact alar ligament, with medial displacement of the fragment into the foramen magnum. Type III OCF are considered potentially unstable because of an avulsed alar ligament

23. Type I
Type II
Type III

24. UNSTABLE:
▪ Occipital condyle fragment displacement >5 mm
▪ Occipito-atlantal dislocation
▪ Bilateral occipital condyle fractures

25. Atlanto-occipital Dislocation
Atlanto-occipital dislocation (AOD) is an uncommon injury that involves complete disruption of all ligamentous relationships between the occiput and the atlas
Stability and function of the atlanto-occipital articulation are provided by the cruciate ligament, tectorial membrane, apical dental ligament, and paired alar ligaments, as well as the articular capsule ligaments
Death usually occurs immediately from stretching of the brainstem, which can result in respiratory arrest

26. >12 mm Basion Dental distance
The lateral cervical spine radiograph is most likely to reveal the injury
Sagittal CT reconstructions or sagittal magnetic resonance imaging (MRI) can allow for the diagnosis when plain radiography is inconclusive.
Atlanto-occipital Distraction
>12 mm Basion Dental distance
Separated occipital condyle and superior surface of C1

27. Atlas (C1) Fractures Generally related to axial loading
Neurologic compromise is relatively infrequent with fractures of the C1 ring, presumably because the axial compression mechanism results in a burst configuration with expansion of the spinal canal
Jefferson Fracture
Lateral Mass (C1) Fracture
Isolated Fractures of C1

28. Jefferson Fracture
Classically, a four-point injury with fractures occurring at the junctions of the anterior and posterior arches with the lateral masses, the weakest structural portions of the atlas
Most commonly there are two fractures in the posterior arch (one on each side) and a single fracture in the anterior arch, off the midline
Mechanism - A JF is created by sudden and direct axial loading on the vertex.
The lateral articular masses of the atlas become compressed between the occipital condyles and the superior articular facets of the axis. By its nature, this is a decompressive injury because the bony fragments are displaced radially away from the neural structures

29. Jefferson Fracture
Most common

30. Plain film findings: Open-mouth odontoid view -
▪ Bilateral offset or spreading of the lateral articular masses of C1 in relation to the apposing articular surfaces of C2
▪ It is often difficult to visualize the lines of fracture per se
Lateral view: (difficult diagnosis on the lateral view)
▪ Increase in the atlanto-axial distance (>3 mm)
▪ Anterior or posterior displacement of the C1 spino-laminar line
▪ The retropharyngeal soft tissue may be abnormal in both contour and thickness

31. Jefferson fracture
Normal

32. CT findings - Axial images:
▪ Identify and establish the sites and number of C1 ring fractures
▪ Establish separation between fracture fragments of the atlas, if >7 mm the lesion is considered unstable
Coronal reconstruction:
▪ Assess offset or spreading of the lateral articular masses of C1 in relation to the apposing articular surfaces of C2
Sagittal reconstruction:
▪ Assess increase in the atlanto-axial distance (>3 mm) and anterior or posterior displacement of the C1 spino-laminar line

33. Unstable (on CT) -
An unstable JF is one in which the transverse ligament is disrupted.
Coronal reconstructions:
▪ Total C1 lateral masses offset of the two sides in excess of 7 mm (adding the amount of lateral displacement of each C1 lateral mass)
Sagittal reconstructions: Increase in the atlantoaxial distance (>3 mm)
Axial views: >7 mm separation between fracture fragments of the atlas
▪ Because multilevel fractures (C1 and C2) are considered unstable, a cautious search for contiguous fractures is critical

34. Lateral Mass (C1) Fracture
Usually occur as a result of a lateral tilt
May be limited to the lateral mass of C1, or more commonly, occurs in association with occipital condyle fractures and/or fracture of the articular process of C2
Usually visible on the open-mouth view
However, sometimes the abnormal cervico-cranial prevertebral soft tissue contour is the only sign of injury in plain films
A fracture of the lateral mass of C1 is considered unstable

35. Lateral Mass (C1) Fracture

36. Isolated Fractures of C1
usually stable
should be distinguished from the Jefferson bursting fracture and its variants
The most common isolated fracture of C1 is a bilateral vertical fracture through the posterior neural arch
Carries no risk of neurologic deficit
This fracture must be distinguished from developmental defects

37. smooth margins of a partially non-ossified posterior atlas ring
Isolated fracture of posterior arch

38. Axis (C2) Fractures
Approximately 25% are hangman fractures, over half (58%) are odontoid fractures, and the remainder are miscellaneous fractures involving the body, lateral mass, or spinous process
Hangman Fracture (Traumatic Spondylolisthesis of C2)
Odontoid Fractures
C2 Lateral Body Fractures

39. Hangman Fracture (Traumatic Spondylolisthesis of C2)
Mechanism –
most common form of this injury results from extension combined with axial loading
Hangman fracture is a bilateral fracture through the pars interarticularis of C2
The pars interarticularis is found between the superior and inferior articular processes of C2
Spinal cord damage is uncommon, despite frequent significant fracture displacement, due to the wide spinal canal at this level

40. Plain film findings -
Lateral view: The fracture usually is diagnosed readily on the lateral radiograph in >90% of cases unless non-displaced.
▪ Prevertebral soft tissue swelling or hematoma, often absent
▪ Fractures are often anterior to the inferior facets. They are oblique, extending from superior/posterior to inferior/anterior
▪ Positive axis ring sign, which will show posterior ring disruption from atypical fractures extending into the posterior C2 vertebral body cortex
▪ “Fat C2 sign”
▪ Posterior displacement of the C2 spino-laminar line of >2 mm,
▪ An avulsion fracture of the anterior margin of the axis or anterior superior margin at C3 is often present and identifies the site of rupture of the anterior longitudinal ligament
AP view: Usually not visible on AP cervical spine radiograph.

41. CT findings -
CT is valuable to exclude or verify fracture line extension into the vertebral foramina or vertebral body, or to detect subtle concurrent adjacent injuries.
Axial images:
▪ Identify the sites of C2 ring fractures and extension into the vertebral foramina or vertebral body.
▪ Establish separation between fracture fragments of the pars inter- articularis of C2
Sagittal reconstruction:
▪ Assess the fractures lines and posterior displacement of the C2 spinolaminar line ▪ Assess C2-3 disc space
▪ Establish separation and angulation between fracture fragments of the pars interarticularis of C2

42. Fat C2 sign
C2 ring sign

43. Classification of the hangman fracture
Type I fracture - an isolated “hairline” fracture, with < 3 mm fragment displacement, < 15-degree angle at the fracture site, and normal C2-3 disc space
Type II injuries - > 3 mm of fragment displacement or more than a 15-degree angle at the fracture site and an abnormal C2-3 disc space
Type III consists - changes that characterize type II injury + C2-3 articular facet dislocation

44. Type I hangman fracture

45. Type II hangman fracture

46. Type III hangman fracture

47. Odontoid Fractures
Classification of dens fractures (Anderson and D'Alonso ) - based upon the location of the fracture site with respect to the dens
Type I - an oblique fracture of the superior lateral aspect of the dens, avulsed by the alar (“check”) ligament; this is an extremely uncommon injury, occurring in < 4% of odontoid fractures
Type II - fracture at the base of the dens (most common - comprising 60% of dens fractures )
Type III - an oblique fracture of the superior portion of the axis body caudal to its junction with the base of the dens

48. Odontoid fractures

49. Odontoid Fractures Plain film findings -
The radiologic diagnosis of odontoid fractures usually is established using the lateral cervical and open-mouth odontoid view radiographs.
Open-mouth odontoid view:
Type II odontoid fractures - transverse or oblique transverse fracture through the lower portion of the dens.
The transverse fracture at the base of the dens must be differentiated from a developmental abnormality termed as os odontoideum.
Os odontoideum is rounded, has a cortical margin around its entire surface, and is usually more widely separated from the base of the odontoid than a fracture, and with smooth margin.
Nonunion odontoid fractures may be impossible to distinguish from an os odontoideum.

50. Lateral view: (Difficult diagnosis on the lateral view)
Minimal displacement often precludes demonstration of the fracture line.
Positive axis ring sign will show posterior or anterior ring disruption in type III fractures
Type III fractures are almost always better visualized on the lateral projection and may not be evident on the anteroposterior view
Anterior or posterior displacement of the C2 spinolaminar line of >2 mm
“Fat C2 sign” in type III fractures

51. Unstable -
If the odontoid fragment is displaced by >5 mm, a 75% nonunion rate results
Odontoid fracture with anterior or posterior displacement of the C2 spinolaminar line of >2 mm
Multilevel fractures (C1 and C2) are considered unstable
Odontoid fractures with atlanto-axial dissociation.

52. Type I odontoid fracture

53. Type II odontoid fracture

54. Type III odontoid fracture

55. Atlanto-axial Dissociation
Defintion - Acute traumatic atlanto-axial dissociation (AAD) is a rare injury in which there is partial (subluxation) or complete (dislocation) derangement of the lateral atlantoaxial articulations
Certain congenital conditions can be associated with AAD, including Down syndrome, osteogenesis imperfecta, neurofibromatosis, Morquio syndrome, spondyloepiphyseal dysplasia congenita, and chondrodysplasia punctata.
Neurologic symptoms occur when the spinal cord is involved

56. Types -
Type I AAD: AAD with rotatory fixation without anterior displacement of the atlas.
This is the most common type of rotatory fixation and occurs within the normal range of rotation of the atlanto-axial joint
Type II AAD: Rotatory fixation with < 5 mm of anterior displacement of the atlas. This is the second most common type and is associated with deficiency of the transverse ligament.
Type III AAD: Rotatory fixation with > 5 mm of anterior displacement of the atlas. This degree of displacement implies deficiency of the TAL .
Type IV AAD: Rotatory fixation with posterior displacement of the atlas. This is the most uncommon type and occurs with deficiency of the dens, such as in type II odontoid process fractures or unstable os odontoideum (congenital or posttraumatic).

57. Atlantoaxial rotatory subluxation associated with left lateral mass of C1 fracture
A: shows rotation of C1 to the right.
B: fracture of the left lateral mass of C1
C: asymmetry of the lateral atlanto-dental spaces (black arrows) and a difference in the atlantoaxial joint spaces (white arrows) secondary to rotational malalignment. Increased transverse diameter of the left lateral mass of C1 (black dot) and truncated appearance on the right (white dot) indicate rotation of C1 to the right.

58. Anterior translation of C1 evidenced by the abnormally wide (>> 5 mm) anterior atlanto- dental interval (AADI)
Anterior position of its spinolaminar line (yellow line in B) with respect to that of C2-3 spinolaminar lines

59. Lower Cervical Spine Injuries (C3-7)
Flexion Injuries –
Cla y-shoveler fracture, Anterior Subluxation , Simple Wedge Compression Fracture, Flexion Teardrop Fracture
Flexion rotation injuries -Unilateral Facet Dislocation
Extension injuries – Dislocation, Extension teardrop fracture, Laminar fractures
Extension rotation – pillar fracture
Vertical Compression - Burst Fracture

60. Clay-shoveler Fracture
Avulsion injury of the spinous process of C6, C7, or T1 (in order of frequency).
The fracture results from abrupt flexion of the head and neck against the tensed ligaments of the posterior aspect of the neck
The name is derived from the cervical spine injury sustained by Australian clay miners
Posterior longitudinal ligament remains intact
The typical clay-shoveler fracture is both mechanically and neurologically stable.

61. Clay-shoveler Fracture

62. Anterior Subluxation
Occurs when posterior ligamentous complexes (nuchal ligament, capsular ligaments, supraspinous and infraspinous ligaments, ligamenta flava, posterior longitudinal ligament) rupture and a minor tear of the annulus posteriorly
The anterior longitudinal ligament remains intact.
No associated bony injury is seen.
Mechanism - Anterior subluxation is caused by a combination of flexion and distraction.
Anterior subluxation is considered clinically significant because of the morbidity associated with the 20% to 50% incidence of failure of ligamentous healing or “delayed instability.”

63. Plain film findings: Lateral view:
The findings of AS seen in neutral position become exaggerated upon flexion and are reduced in extension
Widening of the interspinous distance at one level (“fanning”), relative to adjacent levels
Incongruity and lack of parallelism of the contiguous facets
Disc space is widened posteriorly and narrowed anteriorly
Small anterior superior compression fractures of the subjacent vertebral body
Increased thickness of the prevertebral soft tissues as a result of hematoma formation

65. UNSTABLE:
▪Anterior translation of the vertebral body >3.5 mm relative to the subjacent vertebra
Vertebral body angulation >20 degrees relative to the adjacent vertebra.

66. Simple Wedge Compression Fracture
Mechanism - result of compression of the anterior aspect of the vertebral body
Loss of vertebral body height, predominantly anteriorly
The simple wedge fracture is characterized radiographically by an impaction fracture of the superior endplate of the involved vertebral body while the inferior endplate remains intact
The simple wedge fracture is considered mechanically stable.

67. Bilateral Facet Dislocation
Extreme form of anterior subluxation
Ligamentous disruption and significant anterior displacement of the spine at the level of injury
It usually occurs in the lower cervical spine
The spinal canal is severely compromised by this displacement, and spinal cord injuries are frequent
MRI is the modality indicated for subsequent imaging of patients with BFD as it best assesses the nature and extent of spinal cord injury as well as any associated disc and ligamentous injury

68. Plain film findings: Lateral view: AP view:
Displacement of >50% of the antero-posterior diameter of the vertebral body
Dislocation of articular facets
Narrowing of the disc space at the injured level
Increased thickness of the pre-vertebral soft tissues secondary to hematoma formation.
AP view:
Increased inter-spinous distance at the level of dislocation.

69. Unilateral facet dislocation
25 – 50 %
Anterior subluxation
< 25 %
Bilateral facet dislocation
>> 50 %

70. CT findings:
CT is valuable for detection of radiographically occult fractures of the posterior arch or articular facets.
Axial images:
Fractures undetectable at plain radiography may be revealed.
“Reverse hamburger bun” sign is useful in establishing a diagnosis of facet dislocation
“Naked facet sign”: refers to the CT appearance of uncovered articulating processes on axial CT images.

71. Bilateral facet dislocation – Double vertebral body sign

72. Naked facet sign

73. Flexion Teardrop Fracture
represents the most severe injury of the cervical spine
highly unstable injury
typically involving the lower cervical spine (especially C5)
there is also complete disruption of all soft tissues at the level of injury, including the posterior longitudinal ligament, intervertebral disc, and anterior longitudinal ligament
typical large triangular fracture fragment of the anteroinferior margin of the upper vertebral body (teardrop fragment)
The flexion teardrop fracture can be distinguished from the similarly named hyperextension teardrop fracture by the larger size of the triangular fragment and by distraction of the posterior elements (indicating the flexion mechanism).

76. Hyperextension injuries
most often encountered in elderly patients with severe spondylosis or with spinal ankylosis from other etiologies
Mechanism - In hyperextension fracture dislocation the posterior spinal elements experience impaction forces, producing loading fractures of the posterior vertebral body, laminae, spinous process, or pedicles
Characteristically, the spine above the level of injury is posteriorly displaced (retrolisthesis), the intervertebral disc space is widened anteriorly and narrowed posteriorly and the facet joints are disrupted

77. Hyperextension teardrop fracture

78. Burst fracture

79. Imaging of Thoracolumbar Spinal Injury

80. Thoracic spinal trauma has more chances of neurological damage because
The spinal canal size in the thoracic region averages 16 (AP) by 16 mm (trans), whereas in the lumbar spine the canal averages 17 (AP) by 16 mm (trans)
Thoracolumbar junction is a region of transition and accounts for a greater propensity for injuries in this region - 2/3rd of all thoracolumbar fractures occur at T12, L1, or L2
Thoracic spinal trauma has more chances of neurological damage because
lumbar spine is more capacious
cord terminating as the conus medullaris at the L1 level
cauda equina, unlike the spinal cord, are relatively resistant to blunt trauma

81. Flexion/Compression Injury
typical anterior wedge compression fracture
upper and mid-thoracic spine due to the kyphotic curvature
Neurologic instability is rare in this fracture
Usually involves only the superior endplate
It is distinguished from Scheuermann disease and physiologic anterior vertebral wedging; the latter two usually involve both superior and inferior endplate
Bimodal distribution, occurring in the young (in the context of high-speed trauma) and in the elderly (osteoporosis).
Axial/burst fractures, in contradistinction, have symmetrical reduction in height of the anterior and posterior vertebral margins

83. Axial Load Injury (vertical compression)
burst fractures of the thoracolumbar junction and lumbar spine
classically occurs after landing on both feet or buttocks following a fall from a height (lover's fractures when associated with bilateral calcaneal fractures)
Rarely, due to seizure or electrocution

84. Mechanism –
Axial compression of the vertebral body from above by the nucleus pulposus, which explodes into the superior vertebral endplate to result in centripetal displacement of the body and its fracture fragments
The retropulsion of the posterior aspect of the vertebral body into the spinal canal is pathognomonic of a burst fracture
As the PLL is often intact, spinal traction can reduce this displaced fragment by tightening the PLL

85. Posterior bowing of the vertebral body margin is diagnostic of an axial compression (burst) fracture.

86. Laminar spit fracture

87. Flexion/Distraction Injury
most common at the thoracolumbar junction
separation in a cranial-caudal direction.
Resultant fracture is called Chance’s frcature.
Mechanism - result of hyperflexion of the upper thoracic spine while the lower spine remains relatively fixed
classically caused by a deceleration-type motor vehicle accident

88. “Classic Chance fracture” :
The classic Chance fracture accounts for approximately 50% of Chance-type injuries
A “classic” Chance fracture - consists of a pure osseous injury in which there is a horizontal split through the spinous process, lamina, pedicles, resulting in a small anteroinferior corner fracture of the lower vertebral body
acutely unstable
purely an osseous disruption; it also has excellent healing potential with good prognosis for long-term stability
Incidence of neurologic deficit is low, estimated at 10%

89. AP radiographs - “double” spinous process, interspinous distance widening, and horizontal fractures through the pedicles
lateral radiograph is often unreliable due to overlap
Chance variants –
are either a combined osseous/soft tissue injury or pure
The fracture may extend through the posterior elements as for the classic Chance fracture, but continues anteriorly through the disc or it may involve the posterior ligaments and vertebral body. soft tissue disruption.

91. Shear injury: Severe unstable three column injuty
Shear injury: Severe unstable three column injuty. Neurologic impairment is frequent. High association with thoracic and abdominal injury

92. Extension Injury
The resultant radiographic pattern is characterized by posterior element impaction, with fractures (often comminuted) of the spinous process, lamina, or facets, in association with anterior disc widening or avulsion fracture of the anterior endplate
Mechanism

93. Transverse Process Fractures
The injury should serve as a sentinel sign, alerting one to the possibility of other injury
For example, an isolated L5 transverse process fracture is commonly seen in association with a vertically oriented sacral fracture (Malgaigne fracture/dislocation) on the same side

94. Transverse process fracture associated with a sacral fracture

95. Sacral traumatic fractures
Isolated sacral fractures are uncommon
Transverse fractures-
most common type
Common at S3-S4 level
High horizontal fractures occur from high falls (suicidal jumper’s fracture)
Vertical fractures –
Usually indirect trauma to pelvis
Usually runs entire scrap length

96. Coccygeal fractures Most are transversely oriented
AP radiograph – not useful
Lateral radiography – anteriorly tilted / displaced coccyx

97. Magnetic Resonance Imaging of Acute Spinal Trauma

98. Ligamentous and Joint Disruption
MRI is the only imaging modality available that directly visualizes changes to the ligaments as a result of trauma
ligaments appear relatively hypointense to other structures on all MRI pulse sequences
Edema or tear - increase in signal intensity on T2-weighted or GE images because of an increase in free water content from extracellular fluid or adjacent hemorrhage
Because of the similarity in imaging characteristics, distinction between a ligament fragment and cortical bone fragment may prove difficult on MRI

99. Extensive degenerative changes noted but no gross evidence of malalignment
The ALL, LF and PLL are disrupted.
There is widening of the interspinous distance
Edema in the posterior paraspinal soft tissues
damaged intervertebral disc

100. Disc changes in trauma
can be classified as either disc injury or disc herniation
Disc injury - is implied whenever there is
asymmetric narrowing or widening of an isolated disc space on sagittal images and
focal hyperintensity of the disc material on T2-weighted images
potentially hemorrhagic MR signal changes of a damaged disc may therefore be, in part, due to damage to the adjacent endplates
Disc herniation –
similar MRI appearance to nontraumatic disc herniation

101. acute angulation of C3 on C4 with spinal cord compression
large herniated disc fragment (arrow) compressing the spinal cord
free edge of the ruptured PLL adjacent to the disc fragment

102. Epidural Hematoma
The imaging characteristics of epidural hematomas are variable as they depend on the oxidative state of the hemorrhage and the effects of clot retraction
In the acute phase,
isointense with spinal cord parenchyma on T1-weighted images
isointense with CSF on intermediate- and T2-weighted sequences
The epidural collection may be difficult to distinguish from the adjacent CSF in the subarachnoid space.
This distinction can often be made by the hypointense dura, which separates the two compartments

103. A large dorsal epidural hematoma is displacing the posterior margin of the dura
The roots of the cauda equina are compressed against the vertebral body by the hematoma

104. Spinal Cord Injury
The depiction of parenchymal SCI on MRI not only correlates well with the degree of neurologic deficit, but it also bears significant implications in regard to prognosis and potential for neurologic recovery
Imaging characteristics are due to accumulation of edema and hemorrhage within the substance of the cord parenchyma

105. Spinal cord injury without radiographic abnormality (SCIWORA)
edema within the spinal cord at the C3-4 level (arrow) and prevertebral edema
absence of an obvious fracture or subluxation
Spinal cord injury without radiographic abnormality (SCIWORA)
T2-weighted MRI with fat suppression shows the compression of the spinal cord

106. Spinal Cord Hemorrhage
The most common location is within the central gray matter of the spinal cord
Centered at the point of mechanical impact

107. Two days later, more obvious edema extending down to C4 and clear hemorrhage in deoxyhemoglobin state is seen, particularly on axial GRE (C), where hemorrhage is noted within central portion of spinal cord
small focus of hyperacute hemorrhage at C1-2 (arrow) and very subtle high-intensity edema

108. Spinal Cord Edema
focus of abnormal high signal intensity on T2-weighted images
Edema involves a variable length of spinal cord above and below the level of injury, with discrete boundaries adjacent to uninvolved parenchyma

109. Spinal cord transection

110. Conclusion
Imaging plays a pivotal role in assessing the mechanical and neurologic stability of the traumatized thoraco-lumbar spine.
Radiography is still preferred in low risk “reliable” (awake, alert, normal mental status, and no significant distracting pain) subjects.
CT is the preferred imaging modality in subjects at high risk of injury, however, because of higher sensitivity and specificity.
CT, with the use of high-resolution multiplanar and 3D reformations, has resulted in improved fracture pattern classification with better differentiation between stable or unstable injuries.
MRI is still the only imaging method that demonstrates the soft tissue components of injury and provides an objective assessment of the damaged spinal cord's internal architecture