AJR 2000; 175:661-665
© American Roentgen Ray Society
MR Imaging Findings in Spinal Ligamentous Injury
Philip F. Benedetti1,
Linda M. Fahr2,
Lawrence R. Kuhns3 and
L. Anne Hayman2,4,5
1
Medford Radiological Group, 692 Murphy Rd., Medford, OR 97504.
2
Department of Radiology, Baylor College of Medicine, One Baylor Plaza,
Houston, TX 77030.
3
Department of Pediatric Radiology, F3503, University of Michigan, 1500 E.
Medical Center Dr., Ann Arbor, MI 48109.
4
Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine,
Houston, TX 77030.
5
Herbert J. Frensley Center for Imaging Research, Baylor College of Medicine,
Houston, TX 77030.
Received November 11, 1999;
accepted after revision February 2, 2000.
Presented at the annual meeting of the American Roentgen Ray Society, New
Orleans, May 1999.
Address correspondence to L. A. Hayman.
Introduction
Clinical instability of the spine after trauma occurs when the spinal
ligaments and bones lose their ability to maintain normal alignment between
vertebral segments while they are under a physiologic load. Instability can
lead to further injury, pain, or deformity and can require surgical
stabilization. MR imaging has been shown to be helpful in the detection of
ligamentous injury [1]. The
purpose of this study is to familiarize the reader with the MR imaging
appearance of these injuries. This article is divided into three sections. The
first illustrates injuries to the complex craniocervical junction. The second
reviews the remainder of the spine, and the third addresses the technical
factors that optimize the detection of spinal ligamentous injury.
The importance of these MR findings is increasing as clinicians begin to
compare outcomes and treatments for specific types of ligamentous injury
detected on MR imaging
[2,3,4,5,6,7,8].
As this information grows, so does the power of MR imaging to guide treatment
and to enable prediction of outcome.
Craniocervical Injuries
Many ligaments are seen normally at the craniocervical junction
(Fig. 1). However, only three
are considered the major stabilizers. These are the tectorial membrane
(Fig. 2), the transverse
ligament, and the alar ligaments (Fig.
3). The normal tectorial membrane and transverse ligament are
routinely seen on MR imaging, whereas the normal alar ligaments can be more
difficult to visualize because of lack of contrast from adjacent tissues
(Fig. 3). In most individuals,
each alar ligament arises from the lateral margin of the dens, then courses
laterally in a near-vertical plane, attaching to both the ipsilateral
occipital condyle and the subjacent superior margin of the lateral mass of the
atlas (C1). However, in about a third of individuals, these ligaments insert
solely onto the occiput. The alar ligaments limit axial rotation at the
occipitoatlantoaxial complex. Blood or edema adjacent to an acute alar
ligament tear (Figs. 4 and
5A,5B)
improves visualization of these ligaments. Secondary evidence of ligamentous
injury to one of the alar ligaments is displacement of the dens to the
contralateral side. Isolated posttraumatic alar ligament tears have been
classified. These are clinically significant because hypermobility at the
atlantoaxial joint can reduce blood flow in the contralateral vertebral
artery. Hulse [9] describes
"cervical nystagmus as a manifestation of vertebral artery insufficiency
due to rotatory hypermobility at the occipitoatlanto-axial complex."
Figure
6A,6B
shows displaced ligament injuries at the craniocervical junction associated
with a type II dens fracture.
View larger version (142K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2. —Normal anatomy in 43-year-old woman. Sagittal T2-weighted MR image
(TR/TE, 4500/117) obtained on 0.3-T MR scanner shows normal apical ligament
(1), anterior occipitoatlantal membrane (2), anterior atlantoaxial membrane
(3), anterior longitudinal ligament (4), tectorial membrane (5), dural
reflection (6), posterior occipitoatlantal membrane (7), posterior
atlantoaxial membrane (8), nuchal ligament (9), flaval ligaments (10), area of
interspinous ligaments (11), and supraspinous ligament (12).
|
|
View larger version (146K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3. —Normal anatomy in 38-year-old man. Axial gradientecho or fast
low-angle shot MR image (TR/TE, 420/18; flip angle, 30°) obtained on 1.0-T
MR scanner shows dens (1), presumed anterior atlantodental ligaments (2), alar
ligaments (3), transverse ligament (4), and lateral masses of C1 (5).
|
|
View larger version (129K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4. —Left alar ligament tear in 19-year-old woman with severe neck pain
after fall on her head while snowboarding. Fixed deviation of dens to right
was seen on radiograph (not shown). C1-2 rotatory subluxation was suspected.
Axial T2-weighted MR image (TR/TE, 4000/90) obtained on 1.0-T MR scanner shows
isolated tear of left alar ligament (1) and deviation of dens (2) toward right
with respect to lateral masses of C2 (3). Transverse ligament (4) is intact.
Sagittal images (not shown) depict normal alignment of occipital condyles with
C2, thus no rotatory subluxation is present. CT performed before MR imaging
was negative for fracture and fixed rotatory subluxation. These results
allowed confident symptomatic treatment that led to full recovery.
|
|
View larger version (155K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 5A. —Occipitoatlantal dislocation in 11-year-old boy who was
neurologically intact after motor vehicle crash. Sagittal gradient-echo MR
image (TR/TE, 510/35; flip angle, 20°) obtained on 0.3-T MR scanner shows
intact (1) and torn (2) portions of anterior occipitoatlantal membrane,
anterior arch of C1 (3), intact anterior atlantoaxial membrane (4),
prevertebral edema or hemorrhage (5), torn tectorial membrane (6), torn
posterior occipitoatlantal membrane (7), torn posterior atlantoaxial membrane
(8), intact dural reflection (9), and intact nuchal ligament (10). Before MR
imaging, full extent of injury and degree of instability were not appreciated
either clinically or from results of radiographs or CT scans. Patient
underwent surgical fusion shortly thereafter.
|
|
View larger version (126K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 5B. —Occipitoatlantal dislocation in 11-year-old boy who was
neurologically intact after motor vehicle crash. Axial gradient-echo MR image
(510/35; flip angle, 20°) obtained on 0.3-T MR scanner shows torn right
alar ligament (1), displacement of dens (2) to left with respect to lateral
masses of C2 (3), and intact transverse ligament (4).
|
|
View larger version (173K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6A. —Type II dens fracture in 14-year-old boy who was unrestrained
passenger in motor vehicle crash. Sagittal gradient-echo MR image (TR/TE,
500/9; flip angle, 15°) obtained on 1.5-T MR scanner shows intact
occipitoatlantal membrane (1), anterior dislocation of fractured dens (2),
anterior arch of C1 (3), partial tear of anterior atlantoaxial membrane (4),
cord contusion (5), intact dura (6), medullary contusion or edema (7), torn
tectorial membrane (8), intact posterior occipitoatlantal membrane (9),
posterior arch of C1 (10), torn or attenuated posterior atlantoaxial membrane
(11), intact dura (12), and intact flaval ligaments (13).
|
|
View larger version (139K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6B. —Type II dens fracture in 14-year-old boy who was unrestrained
passenger in motor vehicle crash. Axial gradient-echo MR image (250/15; flip
angle, 15°) obtained on 1.5-T MR scanner shows right lateral mass of C1
(1), anteriorly dislocated dens (2), body of C2 at fracture site (3),
compressed and contused spinal cord (4), anterior arch of C1 (5), intact alar
ligaments (6), and intact transverse ligament (7).
|
|
Cervical, Thoracic, and Lumbar Injuries
Figures 7 and
8 show ligamentous injury
associated with a burst fracture of the cervical vertebrae. Figures
9A,9B,9C,9D,10,11
picture injuries caused by cervical hyperextension. Injuries associated with
interfacetal dislocations and teardrop fractures are also shown in Figures
12,13,14.
View larger version (142K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 7. —Burst fracture of C7 in 30-year-old woman who was unrestrained
driver in motor vehicle crash. Sagittal fast spin-echo inversion-recovery MR
image (TR/TE, 3000/51; inversion time, 140 msec) obtained on 1.5-T MR scanner
shows burst fracture of C7 (1), prevertebral edema or hemorrhage (2), flaval
(3) and interspinous ligament tears (4), with associated distraction of dorsal
spines and spinal cord contusion (5). Also note signal hyperintensity caused
by bone marrow edema in vertebral bodies of C6 and T1.
|
|
View larger version (123K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 8. —Burst fracture of C4 with retropulsion in 17-year-old boy after
motor vehicle crash. Sagittal gradient-echo MR image (TR/TE, 650/13; flip
angle, 15°) obtained on 1.5-T MR scanner shows anterior longitudinal
ligament tear (1), hypointense hemorrhagic cord contusion (2), posterior
longitudinal ligament tear at C3-4 (3), and flaval ligament tear at C4-5
(4).
|
|
View larger version (123K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9A. —35-year old woman involved in head-on motor vehicle collision who
presented with severe neck pain, right arm pain, and numbness. Radiographs and
CT scans (not shown) showed negative findings. Four pulse sequences from a
1.0-T MR scanner at midsagittal level are provided to allow reader to compare
and contrast abnormalities. Findings include disk extrusion and inferior
stripping of posterior longitudinal ligament at C5-6 (1); disk extrusion and
tear of posterior longitudinal ligament and annulus fibrosus at C6-7 (2);
flaval ligament tear at C6-7 (3); splaying of dorsal spines and interspinous
ligament tear at C6-7 (4); fracture of C6 spinous process (5); and mild
superior endplate impaction fractures of T1, T2, and T3 vertebral bodies (6).
Solely on basis of results of MR images, the following day patient was started
in traction and taken to surgery where anterior diskectomy and fusion at C5-6
and C6-7 were performed. Patient experienced immediate marked improvement in
symptoms after surgery. Fast spin-echo inversion-recovery sagittal MR image
(TR/TE, 4000/60; inversion time, 140 msec) best shows bone marrow edema caused
by fracture or trabecular contusion, spinal cord injury, and soft-tissue
edema.
|
|
View larger version (124K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9B. —35-year old woman involved in head-on motor vehicle collision who
presented with severe neck pain, right arm pain, and numbness. Radiographs and
CT scans (not shown) showed negative findings. Four pulse sequences from a
1.0-T MR scanner at midsagittal level are provided to allow reader to compare
and contrast abnormalities. Findings include disk extrusion and inferior
stripping of posterior longitudinal ligament at C5-6 (1); disk extrusion and
tear of posterior longitudinal ligament and annulus fibrosus at C6-7 (2);
flaval ligament tear at C6-7 (3); splaying of dorsal spines and interspinous
ligament tear at C6-7 (4); fracture of C6 spinous process (5); and mild
superior endplate impaction fractures of T1, T2, and T3 vertebral bodies (6).
Solely on basis of results of MR images, the following day patient was started
in traction and taken to surgery where anterior diskectomy and fusion at C5-6
and C6-7 were performed. Patient experienced immediate marked improvement in
symptoms after surgery. T1-weighted MR image (500/15) is helpful in showing
anatomic detail and alignment and in detecting fracture.
|
|
View larger version (130K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9C. —35-year old woman involved in head-on motor vehicle collision who
presented with severe neck pain, right arm pain, and numbness. Radiographs and
CT scans (not shown) showed negative findings. Four pulse sequences from a
1.0-T MR scanner at midsagittal level are provided to allow reader to compare
and contrast abnormalities. Findings include disk extrusion and inferior
stripping of posterior longitudinal ligament at C5-6 (1); disk extrusion and
tear of posterior longitudinal ligament and annulus fibrosus at C6-7 (2);
flaval ligament tear at C6-7 (3); splaying of dorsal spines and interspinous
ligament tear at C6-7 (4); fracture of C6 spinous process (5); and mild
superior endplate impaction fractures of T1, T2, and T3 vertebral bodies (6).
Solely on basis of results of MR images, the following day patient was started
in traction and taken to surgery where anterior diskectomy and fusion at C5-6
and C6-7 were performed. Patient experienced immediate marked improvement in
symptoms after surgery. T2-weighted fast spin-echo MR images (3500/90), like
this one, are often best for showing ligaments, blood in spinal cord, bone
marrow edema, and soft-tissue edema.
|
|
View larger version (130K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9D. —35-year old woman involved in head-on motor vehicle collision who
presented with severe neck pain, right arm pain, and numbness. Radiographs and
CT scans (not shown) showed negative findings. Four pulse sequences from a
1.0-T MR scanner at midsagittal level are provided to allow reader to compare
and contrast abnormalities. Findings include disk extrusion and inferior
stripping of posterior longitudinal ligament at C5-6 (1); disk extrusion and
tear of posterior longitudinal ligament and annulus fibrosus at C6-7 (2);
flaval ligament tear at C6-7 (3); splaying of dorsal spines and interspinous
ligament tear at C6-7 (4); fracture of C6 spinous process (5); and mild
superior endplate impaction fractures of T1, T2, and T3 vertebral bodies (6).
Solely on basis of results of MR images, the following day patient was started
in traction and taken to surgery where anterior diskectomy and fusion at C5-6
and C6-7 were performed. Patient experienced immediate marked improvement in
symptoms after surgery. Gradient-echo MR images (500/18; flip angle, 30°),
like this one, are often best for showing ligaments and blood in spinal
cord.
|
|
View larger version (151K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 10. —Hyperextension injury in 71-year-old man who fell from bicycle and
presented with central cord syndrome. Sagittal T2-weighted MR image (TR/TE,
4500/117) obtained on 0.3-T MR scanner shows flaval ligament hypertrophy (1),
C5-6 posterior disk protrusion (2), anterior longitudinal ligament tear, and
partial disruption of C5-6 intervertebral disk (3).
|
|
View larger version (170K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 11. —6-year-old boy with cervical spine hyperextension injury during
motor vehicle crash. Sagittal fast spin-echo inversion-recovery MR image
(TR/TE, 3000/51; inversion time, 140 msec) obtained on 1.5-T MR scanner shows
horizontal fracture through inferior endplate of C6 (1), posterior
longitudinal ligament tear (2), cord contusion (3), anterior longitudinal
ligament tear (4), prevertebral hemorrhage or edema (5), and extradural
hemorrhage (6). MR imaging findings guided therapy resulting in anterior
surgical fusion.
|
|
View larger version (126K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 12. —Bilateral interfacetal dislocation at C4-5 in 62-year-old man
involved in motor vehicle crash. Sagittal gradient-echo MR image (TR/TE,
510/35; flip angle, 20°) obtained on 0.3-T MR scanner shows prevertebral
edema or hemorrhage (1), posterior longitudinal ligament tear (2), anterior
longitudinal ligament tear (3), large traumatic posterior disk extrusion (4),
cord contusion and compression (5), posterior paravertebral edema or
hemorrhage, and probable interspinous ligament injury (6).
|
|
View larger version (121K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 13. —Bilateral interfacetal dislocation in 42-year-old woman involved in
motor vehicle crash. Sagittal T2-weighted MR image (TR/TE, 4500/117) obtained
on 0.3-T MR scanner shows tear of dura and posterior atlantoaxial membrane
(1), partial tear of nuchal ligament (2), distraction of C5-6 spinous process
and torn interspinous ligaments (3), torn flaval ligaments (4), torn posterior
longitudinal ligament (5), and torn anterior longitudinal ligament (6).
|
|
View larger version (119K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 14. —Teardrop fracture of C7 in 27-year-old man involved in motor vehicle
crash. Sagittal gradient-echo MR image (TR/TE, 510/35; flip angle, 20°)
obtained on 0.3-T MR scanner shows extensive posterior paravertebral edema or
hemorrhage and probable tearing of interspinous ligaments (1), partial tear of
nuchal ligament (2), flaval ligament tear (3), partial tear of posterior
longitudinal ligament (4), anterior superior corner fracture of C7 vertebral
body (5), stripping of anterior longitudinal ligament from anterior surface of
C7 vertebral body (6), and prevertebral edema or hemorrhage (7).
|
|
The concept of three columns of support in the thoracic and lumbar spine is
well accepted. The same principles have been applied to the C3-C7 vertebral
levels in the cervical spine. Stability is provided by intact osseous and
ligamentous structures. The anterior column consists of the anterior vertebral
body, the anterior longitudinal ligament, and the anterior annulus fibrosus.
The middle column comprises the posterior vertebral body, the posterior
longitudinal ligament, and the posterior annulus fibrosus. Hyperextension can
result in injury to the anterior column
(Fig. 10) or to both the
anterior and middle columns (Figs.
11 and
15). The posterior column
consists of the posterior elements of the spine, ligamentum flavum,
interspinous ligaments, supraspinous ligaments, and facet joint capsules.
Hyperflexion may result in injury to the middle and posterior columns (Figs.
9A,9B,9C,9D
and
16A,16B).
Injury to any two adjacent columns will result in instability. Disruption of
all three osseous or ligamentous supporting columns is shown in association
with burst fractures in Figures
7 and
8, bilateral interfacetal
dislocation is shown in Figures
12 and
13, and teardrop fractures of
C7 are shown in Figure 14.
View larger version (144K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15. —Ligament stripping in 450-lb (202.5-kg) 35-year-old man ejected from
motor vehicle. Lateral radiographs (not shown) were nondiagnostic. Sagittal
gradient-echo MR image (TR/TE, 510/35; flip angle, 20°) obtained on 0.3-T
MR scanner shows anterior longitudinal ligament stripped completely away from
anterior surface of midthoracic spine vertebral body (1). Similarly, posterior
longitudinal ligament is stripped away from posterior vertebral body surface
at level of fracture-subluxation (2). Adjacent intervertebral disk is
disrupted (3) and thoracic spinal cord is compressed (4).
|
|
View larger version (146K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 16A. —11-year-old boy who suffered flexion-distraction injury from lap
belt during motor vehicle crash with fractures at L4 level. Sagittal
gradient-echo MR image (TR/TE, 500/13; flip angle, 15°) obtained on 1.5-T
MR scanner shows large presumed cerebrospinal fluid leak into posterior
subcutaneous tissues (1), distracted fracture fragments of left L4 articular
processes (similar fracture was also present on right) (2), and distracted
fracture, near horizontal in orientation, involving posterosuperior portion of
L4 vertebral body (3).
|
|
View larger version (138K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 16B. —11-year-old boy who suffered flexion-distraction injury from lap
belt during motor vehicle crash with fractures at L4 level. Sagittal
gradient-echo MR image (500/13; flip angle, 15°) obtained on 1.5-T MR
scanner of midline shows distraction of spinous process of L3 and L4 (1),
supraspinous ligament tear (2), and flaval ligament tear (3).
|
|
Imaging Considerations
Successful MR imaging of spinal trauma depends on several factors. One of
these is the timing of the study. Although no research has yet, to our
knowledge, defined the optimal time interval between injury and MR imaging, it
should probably be less than 72 hr
[8]. Beyond this time,
resorption of the edema or hemorrhage reduces sensitivity of MR imaging to
reveal injuries. Specifically, the T2 signal hyperintensity produced by edema
or extravasation of blood into injured extradural tissues provides an
excellent contrast medium, improving the conspicuity of the ligaments that are
usually of low signal intensity on all imaging sequences.
The use of appropriate sequence parameters for MR imaging is also
important. These parameters vary widely according to the field strength, coil
design, gradient strength, and software capabilities of the MR imaging system
used. Thus, each system requires an individualized approach, fine-tuned by
trial and error. In general, field of view, slice thickness, matrix, and
signal averages must be chosen to balance the effects on signal-to-noise
ratio, spatial resolution, and imaging times. For example, longer imaging
times may improve scan quality but provide more opportunity for patient
motion. A typical MR imaging protocol for spinal trauma should include the
following sequences in the sagittal plane: T1-weighted, fast spin-echo
T2-weighted, gradient-echo, and fast spin-echo inversion-recovery images. In
the axial plane, protocol should include gradient-echo or T2-weighted images.
Optional coronal T1-weighted or gradient-echo sequences can aid in evaluation
of the cranioatlantoaxial segment, especially with regard to alignment and
dens fracture. Figure
9A,9B,9C,9D
compares the relative merits of the four sagittal sequences described
previously. T1-weighted images provide the best anatomic detail, accurately
depict alignment, and are invaluable for detection of fracture. Ligaments are
usually best seen on gradient-echo and T2-weighted sequences. At high field
strength, the heterogeneity effect produced by gradient-echo imaging
techniques results in greater sensitivity for detection of blood products
within the spinal cord but also reduces signal intensity within bone and makes
fracture detection more difficult. At low field strength, the gradient-echo
heterogeneity effect is weaker so that blood products are less easily detected
but fracture detection is somewhat improved. T2-weighted and fast spinecho
inversion-recovery sequences are most sensitive for bone marrow edema (caused
by fracture or trabecular contusion), spinal cord injury, and soft-tissue
edema. Cerebrospinal fluid pulsatility artifacts and truncation artifacts can
sometimes interfere with spinal cord evaluation on T2-weighted and fast
spin-echo inversion-recovery sequences.
Conclusion
MR imaging of the posttraumatic spine is a rapidly evolving technique with
the potential to revolutionize the evaluation and treatment of ligamentous
injuries. In our clinical experience, it has been an invaluable adjunctive
technique, particularly in patients with relevant neurologic deficits and
those requiring closed reduction of a posttraumatic spinal subluxation. It has
also been helpful in evaluating spinal trauma complicated by altered
sensorium, extreme obesity, or even malingering.
References
-
Katzberg RW, Benedetti PF, Drake CM, et al. Acute cervical spine
injuries: prospective MR imaging assessment at a level 1 trauma center.
Radiology
1999;213:203
-211[Abstract/Free Full Text]
-
Keiper ZRA, Bilaneui LT. MRI assessment of the supportive soft
tissues of the cervical spine in acute trauma in children.
Neuroradiology
1998;40:359
-363[Medline]
-
Halliday AL, Henderson BR, Hart BL, Benzel EC. The management of
unilateral lateral mass/ facet fractures of the subaxial cervical spine.
Spine
1997;22:2614
-2621[Medline]
-
Davis SJ, Teresi LM, Bradley WG, Siemba MA, Bloze AE. Cervical
spine hyperextension injuries: MR findings. Radiology
1991;180:245
-251[Abstract/Free Full Text]
-
Brightman RP, Miller CA, Rea GL, Chakeres DW, Hunt WE. Magnetic
resonance imaging of trauma to the thoracic and lumbar spine: the importance
of the posterior longitudinal ligament. Spine
1992;17:541
-550[Medline]
-
Saifuddin A, Noordeen H, Taylor BA, Bayley I. The role of imaging
in the diagnosis and management of thoracolumbar burst fractures: current
concepts and a review of the literature. Skeletal
Radiol 1996;25:603
-613[Medline]
-
Petersilge CS, Pathria MN, Emery SE, Masaryk TJ. Thoracolumbar
burst fractures: evaluation with MR imaging. Radiology
1995;194:49
-54[Abstract/Free Full Text]
-
Selden NR, Quint DJ, Patel N, d'Arcy HS, Papadopoulos SM. Emergency
magnetic resonance imaging of cervical spinal cord injuries: clinical
correlation and prognosis. Neurosurgery
1999;44:785
-792[Medline]
-
Hulse M. Differential diagnosis of vertigo in functional cervical
vertebrae joint syndromes and vertebrobasilar insufficiency [in German].
HNO
1982;30:440
-446[Medline]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
C. J. Edge, N. Hyman, V. Addy, P. Anslow, C. Kearns, R. Stacey, and C. Waldmann
Posterior spinal ligament rupture associated with laryngeal mask insertion in a patient with undisclosed unstable cervical spine
Br. J. Anaesth.,
September 1, 2002;
89(3):
514 - 517.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Introduction
Craniocervical Injuries
