The Cervical vertebrae - ASNR



The Cervical vertebrae

If one were to attempt design the cervical spine as a project for a PHD in an engineering school, we would be faced with a remarkable challenge. How do we create a structure that is strong enough to support the head yet flexible enough to allow us to watch our backs in a dark alley? This is further complicated by the requirement that the structure contains and protects the spinal cord and the exiting nerve roots, which are extraordinarily delicate.

Nature has provided a remarkable structural compromise. The weight of the head is born primarily by the vertebral bodies and lateral masses. The intervening discs behave as deformable cushions that permit motion. The shape of the articular processes, the flexibility of the joint capsules and supporting muscles, tendons and ligaments along with the deformability of the intervertebral disc, determine the limits of motion.

It is useful to separate the cervical spine into two functional zones, A) the cranio-cervical junction which we will arbitrarily define as extending from the superior end plate of C3 to the inner rim of the foramen magnum and B) the remainder of the cervical spine.

The spine has three functions. What are they?

Function 1) The lumbar and thoracic spine function to keep the body erect. The cervical spine must hold the head erect so that the eyes face forward.

Function 2) Protect the spinal cord and nerve roots.

Function 3) Allow mobility

Every time we look at an imaging study, it is our role as radiologist, to determine how well the spine accomplishes each of these tasks. It important for the trainees in radiology to get in the habit of specifically forming an opinion about each of these 3 functions. The details of the report of the imaging study should depend on the recognition of any functional failure of the spine.

What other information other than spinal function should we analyze when looking at films?

We get important information as to the health of the patient’s bone. We must evaluate the relative mineral content as well as structural integrity.

No text 9

Slide 10) As previously mentioned, when evaluating any imaging study of the cervical spine, one must determine how well the neck is succeeding in holding up the head. The normal cervical spine has a gentle lordotic curve. This curve is very variable in normal people and depends on the position and angle of the head. A straight cervical spine is not necessarily abnormal. Reversal of the curvature or a focal deformity of the curvature is abnormal.

The cervical vertebral bodies are cylinders having a dense cortical border and a more compressible inner matrix. The heights of the intervertebral disc spaces either remain the same or increase as one descends down the cervical spine. A normal disc may never be narrower than its next highest mate.

Function 1 Holds up the head (2)

Slide 11) The spine should be straight in the frontal plane. The head being held erect with the eyes projecting forward. The spinous process although very variable in shape, should project in the midline. Lateral bending of the neck is limited by the height of the disc spaces and the uncinate processes. It would be totally impossible, however, if it were not for simultaneous rotation of the zygapophiseal joints. In order to bend or tilt the head to the side, the superior articular processes on the outside of the curvature slide upward upon its lower mate and the superior articular process on the inside of the curve, slide downward on its mate.

Slide 12) Here is a radiograph to evaluate. Is the curvature of the spine normal or abnormal? Click below to check your answer.

Slide 13) Remember that the curvature of the neck is dictated by the position of the patient’s body and head. One can straighten or flex the neck at will.

Slide 14) Try this film.

Slide 15) Angulations of the spine and reversal of the normal lordosis is not normal. No one can voluntarily bend the neck in such a way that the normal gentle curve is broken and reversed.

Slide 16) The spinal cord is enclosed within a water sack surrounded by two separate insulating cushions. All of the above lie within a bony canal. It is obvious that if our engineering project were to optimize the spine to protect the spinal cord the bony ring would be complete and non-flexible. However the real spinal canal is made of a chain of vertebra connected by soft tissue. The spinal cord within the bony ring is well protected and is rarely injured except with bony catastrophe. The spinal cord segments between the bony rings are much more liable to be injured even without catastrophic bony injury. The width of the spinal canal is most often estimated from lateral radiographs. It is usually possible to measure the AP diameter from the posterior edge of the vertebral body to the inter-laminar line.

What are the 2 other protective cushions?

Function 2 Protect the neural structures

Slide 17) The epidural veins act as a second fluid cushion. The epidural fat, which acts as the third cushion, can be considered as if it was the Styrofoam within the bony box of the spinal canal. Neural compression is very unlikely when the nerve roots are surrounded by epidural fat.

Function 3

Slide 18) The integrity of the bony neural ring is best evaluated by cross sectional imaging in the axial plane. The cross sectional area of the spinal canal is determined by, among other things, the shape of the vertebral body. Flat or convex posterior vertebral bodies tend to have larger canals than vertebrae which are convex towards the canal.

The cryomicrotome section and the adjacent drawing document the relationship of the neural structures to the bony ring. There is very little epidural fat in the cervical spinal canal.

Slide 19) The term “neural foramen” is a misnomer. Foramen implies an opening like a door. Actually the nerves exit through a canal with an entrance zone, a mid zone and an exit zone. The roots lie in a groove within the transverse process posterior to, and in contact with, the vertebral arteries.

Lateral x-ray

Slide 20) Let us now review that which is seen on lateral radiographs of the cervical spine.

A properly positioned lateral radiograph will project the central ray of the beam though the middle of the neck. The vertebral endplates will therefore parallel one another. The anterior corners of the bodies are usually asymmetric. The inferior corners tend to point downward. The superior corners are either straight or slightly beveled. This beveling is due to variations in ossification of the anterior ring apophyses.

Lateral x-ray 2

Slide 21) The cortical margins of the vertebral bodies form a gentile lordotic curve. There should be no angles or steps.

The anterior faces of the laminae appear as crescents of cortical bone which, when connected, form the interlaminar line. The interlaminar line should parallel the course of the curve of the posterior vertebral bodies.

Slide 22) There are many published criteria for evaluating the size of the spinal canal. I would suggest however, a very simple way of evaluating the size of the canal which I have called the Pinky test. For all but the shortest people, the pinky should fit within the spinal canal. Very short people should use the 4th finger.

Slide 23) Does this patient have a small spinal canal or not?

Slide 24) This patient fails the pinky test. The canal is congenitally small and made smaller by bony osteophytes. Did you notice the ossification of the posterior longitudinal ligament?

Lateral x-ray 3

Slide 25) The articular pillars project over the spinal canal on the lateral radiograph. The articulating surfaces of each pair of joints are usually superimposed one upon the other. One does, however get a sense of their integrity. The facets should be smooth and regular with a well-defined cortical bony margin. The joints are superiorly angled approximately 30 degrees.

Slide 26) The transverse processes through which traverse the vertebral arteries can be seen superimposed upon the vertebral bodies. Note the trough-like appearance. The exiting nerves lie upon these troughs.

Oblique Radiograph

Slide 27) The complete radiographic analysis of the cervical spine includes two oblique views. On these images one can see the length of the neural foramina, the articular processes, and the uncovertebral joints. The neural foramen is a keyhole shaped structure.

Slide 28) Another view showing the channel which is called the neural foramen. The uncinate process and unco-vertebral joint in indicated by the blue arrows.

Oblique radiograph close up

Slide 29) The exiting nerve lies upon the transverse process in the inferior portion of the foramen. The superior, lateral border of the foramen is primarily soft tissue, being made up of the zygapophiseal joint capsule. Bony spurs arising from a degenerative joint, project downward on the nerve from the posterolateral capsule. Uncinate spurs project directly into the exiting nerve.

Slide 30) Here is a typical oblique cervical radiograph. Does this patient have foraminal stenosis?

Slide 31) There is no substitute for flawless technique.

Frontal Radiograph

Slide 32) The frontal radiograph is often neglected as an important diagnostic tool. The spinous processes project through the vertebral bodies and should align in the midline. There is considerable variation in their size and shape but the distance between each of them is quite consistent. The cervico-thoracic junction is well seen and the upper ribs and pulmonary apices are optimally seen.

Frontal Radiograph

Slide 33) The central ray of the x-ray beam is usually parallel to the vertebral end plates of the lower vertebrae. Consequently they are well seen. The central ray of the beam is never normally parallel to the zygapophiseal joints consequently the joint surfaces are not visualized.

The uncovertebral joints are easily discernable in this view.

Frontal Radiograph

Slide 34) The neural arches can be seen projecting through the vertebral bodies. One can actually follow the entire arch out to the transverse process.

Pillar Views

Slide 35) In order to optimally visualize the lateral masses it is necessary to angle the central ray parallel to the plane of the joints. This is accomplished by having the patient lie supine with the chin slightly elevated if possible. The patient then turns the head to the side and the x-ray beam is angled caudally. This projection is ideal for the evaluation of fractures and arthritis.

Pancost

Slide 36) Can you determine the exact cause of this patient’s neck pain?

Pancost tumor

Slide 37) It is never possible to determine if a degenerated disc is causing neck pain because so many normal people have degenerative disease with no pain. Abnormal curvature may be due to pain but is not the cause of pain. The lateral view does not help us here at all. On the frontal radiograph we can identify a soft tissue mass at the pulmonary apex. Remember that the pulmonary apices are best seen on lordotic chest views and AP views of the neck.

OPLL

Slide 38) Describe at least 4 abnormalities on this film. Then determine if you can if the spine has failed or not. If it has, which function has failed?

OPLL

Slide 39) This patient has Diffuse Idiopathic Skeletal Hyperostosis with crests of bone projecting from the vertebral edges. The C5/6 disc is degenerated. The spinal canal is congenitally small. The spine has failed, however, because of a large plaque of ossification of the posterior longitudinal ligament causing myelopathy.

Slide 40) Another quiz case. Has the spine failed here, if it has, in what way?

Slide 41) This is quite an abnormal radiograph. There is severe degenerative disc disease at C 5/6, and disc space narrowing at C3/4. There is abnormal curvature of the spine. The spine has failed in its supportive function because of a metastatic lesion of the C 3 vertebra.

Flexion –Extension.

Slide 42) It is occasionally important to evaluate the limits of motion of the cervical spine. This may be done with lateral radiographs in maximum flexion and extension. As the head moves into the flexed position, the superior articular processes glide upward and forward. The discs deform to allow the motion. The anterior margins of the discs narrow and the posterior portion of the discs widen. This is normal. Each vertebra moves slightly forward upon its next lower mate. The distance between the spinous processes will widen but the widening should remain proportionate between the motion segments.

Flexion extension

Slide 43) In extension the reverse occurs. The spinous processes come closer together. The superior articular processes glide downward. The anterior portion of the disc widens and the posterior portion of the disc narrows. The C5/6 tends to open and close slightly more than the other levels perhaps because it is usually the most mobile segment.

Video fluoroscopy

Slide 44) It is possible to use standard Video fluoroscopy to evaluate neck motion. Cervical motion is quite complex. We will focus now on the lower spine. Click on the word motion to view the video clip. Windows media player will run. It is possible to enlarge the screen by clicking in the appropriate box on the player bar. I suggest you replay the video several times while listening to the discussion. On each run, focus your attention on a single anatomical feature and watch how that structure moves.

The most important thing to observe is the sequence of vertebral motion. Motion begins at the craniovertebral junction and descends in an orderly fashion throughout the cervical spine. There should never be asynchrony of motion. The segments should never move before their next higher mate. Premature motion is an important sign of segmental instability and ligamentous laxity or injury.

Note first how the head rocks forward on C1. C1 flexes on C2 followed by each sequential vertebra. Concentrate only on the anterior edges of the vertebral bodies. Repeat the process looking at the posterior bony edges of the vertebra and then the interlaminar line. Note how the spinous processes diverge in flexion and appose in extension.

Slide 45) How has the spine failed here?

Slide 46) This patient has Swan neck deformity caused by wide posterior laminectomy. C3 is fused to C4 and the C4-C5 disc has become hypermobile. The spine has failed all three of it functions. The spinal cord is no longer protected by a bony ring. The spine is unable to move normally because of the fusion and the hypermobile segment, and the head is held up abnormally.

Cervical dynamics MRI

Slide 47) It is possible to perform MRI in flexion or extension. Several different techniques have been devised to show what the discs and joints look like in different phases of motion. This series was performed throughout the dynamic range from flexion to extension. Note how the normal discs change shape when flexed and extended. The anterior annulus bulges in flexion and the posterior annulus bulges in extension.

Slide 48) This patient complained of bilateral leg weakness and bowel and bladder problems. A diagnosis of spondylitic myelopathy was made and a wide posterior decompression was performed. How successful do you think the surgery was?

Slide 49) This surgery failed. The patient was having increasing signs of spinal cord compression especially in the upper extremities. Can you determine to most likely cause?

Slide 50) Two abnormalities are documented on the extension MR image. The bulging disc at C3-4 has increases in size. The most important finding, however, is that the contracted muscles of the posterior neck are pressing the spinal cord forward against the discs, osteophytes and the back of the vertebral bodies. It is important to note that the area of maximal cord compression is not at the C3/4 level where the disc is bulging but behind the C 5 vertebra. It is critical not to become a disc fixated radiologist.

Slide 51) Part 2

Slide 52) We begin our tour through the cervical spine with axial views of atlas and axis. C1 is a specialized vertebra that attaches the skull to the mobile spine. The superior articular processes are concave crescents, which articulate with the convex occipital condyles. There is never any rotation or lateral bending possible between the skull and C1. The skull does flex and extend on C1.

Slide 53) The anterior arch of C1 prevents the head from falling backwards in extension.. The powerful transverse ligament, which holds the dens in place, attaches from two small tubercles on the inner surface of the C1 ring.

Slide 54) Sagittal reformatted CT of the occipital condyles and the superior articular processes of C1 show the distinctive concave shape of the C1 facet and the convex surface of the occipital condyle. It is obvious why flexion is possible in a joint of this shape while rotation is not.

Slide 55) C2 acts as the pivot of rotation of the skull. The joint between the C1 ring and the dens is a typical synovial joint and can manifest all the abnormalities of any other joint. The superior articular processes of C2 are shaped like airplane wings. The surface is convex sloping downward both anteriorly and posteriorly. The transverse ligament is well seen in this plane.

Slide 56) To review: The C1 ring acts as a rotating base for the skull. It allows 90 degrees of rotation, no lateral bending and a short arc of forward bending. The dens of the C2 vertebra, provides the pivot for the skull. It is much less substantial than a normal vertebral body and does not have a significant role in supporting the weight of the head. Because of this the base of the peg of the dens is a relatively weak structure and is often fractured

Slide 57) It is important to understand the embryology of the Cranio vertebral segments because of the many complex anomalies that occur. The C1 ring is partially ossified at birth. The anterior and posterior arches are the last to ossify and the most common areas to fail to ossify in adults.

Slide 58) At birth, there are ossification centers for the vertebral body of C2, the body of C1, which will ultimately become most of the dens, and two lateral ossification centers. The tip of the dens is not ossified at birth. It forms from cartilage from the 4th occipital somite.

The diagram on the left is of the ossification centers as seen in the adult C2 vertebra. Note that the fusion planes between the fetal ossification centers remain visible in adult life as areas of bone condensation. The importance of this will be made clear later in this course.

Slide 59) The sagittal plane is best for evaluating the stability of the cranio vertebral joint. All CT examinations should include thin section sagittal and coronal reformations to exclude subtle pathology. The space between the C1 ring and the dens should always be closed on CT or MR since they are performed in the supine position. In the upright position 2mm of space between C1 and the dens is acceptable. Note that the epidural space of the cervical spine ends at the foramen magnum with the attachment of the ligaments to the base of the skull.

Slide 60) Coronal CT or MR demonstrate the internal structure of C2. The vestigial C1/C2 disc space is seen.

Slide 61) The fusion plane of the two halves of the dens appears as a sclerotic line down the center of the dens.

Slide 62) The terminal ossicle fuses to the rest of the dens in childhood and is identified by the “V” shaped notch at the apex of the den.

Slide 63) In the frontal plane, the alar ligaments can be identified extending from the dens to the lateral side of the foramen magnum. These two small structures limit the rotation of the head on C2. The alar ligaments are not tight structures.

They allow as much as 90 degrees of rotation at the C2 level. Injury of the alar ligaments can only be evaluated in the axial plane.

Slide 64) As mentioned earlier, the superior articular facets of C2 and the inferior articular facets of C1 are convex sloping structures. As rotation occurs, one C1 facet glides forward and downward upon its mate while the contra lateral facet glides backwards and upwards. The joint capsules of these joints are very loose structures. There may be 5mm or more of apparent subluxation of these facets from the normal range of motion.

Slide 65) Routine AP radiographs of the C1-C2 level are performed with the mouth open. The dens should project in the center of the open mouth. The spinous process of C2 must be seen in the midline as well. Knowing the position of the spinous process of C2 is critical in the evaluation of the cranio-vertebral junction on radiographs. On these two Netter drawings, note the convex, airplane wing shape of the superior articular facets.

Slide 66) In the non rotated neutral AP plane the articular facets align symmetrically. The dens should sit in the center of the space between the articular processes. Note that in the neutral position the spinous process of C2 is in the midline.

Slide 67) These drawings of C1 and C2 done by Dr. Youngberg, demonstrate the complex relationship of the facets and spinous process of C2 with varying degrees of rotation. In all views, the C2 vertebra remains in the neutral position facing forward. In the top row center a forward facing C1 is superimposed. In the middle of the lower row the head is in neutral position. On either side the head is rotated to the right or to the left. Note that as the spinous process of C2 moves one way, the articular processes on the opposite side appear to sublux. These are very complicated drawings. Spend the time to really understand the relationship between the facets in rotation.

Slide 68) Note also that the bean shaped articular processes of C1 move with respect to the dens. As the head turns to the right the left articular processes glides forward and medial and comes closer to the dens. As the head turns to the left the opposite occurs.

Slide 69) Diagrams in the frontal plane corresponding to the axial views we have been discussing, show what happens to the space between the dens and the articular pillars with rotation. As the head turns to the right the left articular process appears to elongate and the distance between it and the dens narrows. At the same time the articular process on the right appears to shorten and the distance between it and the dens increases.

Slide 70) In the neutral position where the spinous process of C2 is in the midline, the articular processes are symmetrical, the distance between each of them and the dens is the same and there is no overhang of the articular processes laterally.

Slide 71) This is a frontal view on a patient with neck pain. Is this radiograph indicative of cervical pathology or not?

Slide 72) This is a normal film with the patients head turned from the center. The spinous process is not in the midline. The left articular process appears longer than the right and the right appears to be offset from the superior articular process of C2. The relationship of C1 to C2 looks abnormal but isn’t. One can not make any statement about abnormal position, if the spinous process is not in the midline on the radiograph.

Slide 73) What about this case? Is this normal or abnormal?

Slide 74) This is clearly abnormal. The spinous process of C2 is in the midline but there is offset of both articular pillars of C1. This can only occur when the ring of C1 is broken. This is the hallmark of a Jefferson Fracture.

Slide 75) What country am I in?

Slide 76) Before attempting to make a specific diagnosis of any problem, one must get an overview of the problem. Decide what forest we are in before getting more specific. In the context of spinal imaging that means that one should try to determine what broad classification the disease processes appears to fall into. Then by making specific observations one can often come to a specific diagnosis. A recitation of random anatomical abnormalities in a radiological report is not nearly as useful as a molded statement of findings within the context of the overall “big picture”. Did you notice that I am in a bamboo forest? I’m probably in Japan or China not likely at home in Southern California.

Slide 77) Is this normal or abnormal based on our previous discussion?

What specific anatomical observations can you make here? Leave the diagnosis for the end. Click to see what I think are the important observations.

Slide 78) First note the position of the spinous process. It is in the midline. There is offset of both articular pillars to the same side. The dens appears to be eccentric to the patients left.

Slide 79) This patient has a type 2 den fracture. The fracture line is obvious. The base of the dens is offset and the edges are jagged.

Slide 80) What are the key observations here? After making the observations what is the diagnosis?

Slide 81) The head is rotated to the right, the spinous process of C2 is rotated to the left. The dens appears eccentrically placed between the articular pillars of C1. I have said that one should make little of the dens position in a film with the spinous process not in the midline. Here, however, with the head turned to the right, we would expect the left articular process to appear to elongate and come closer to the dens. The opposite has actually occurred here. This is always objectively abnormal. There is a fracture line below the base of the dens extending into the vertebral body indicating that the patient has a type 3 dens fracture. It is important to distinguish between types 2 and 3 dens fracture because type 3 fractures nearly always heal even with relatively poor immobilization of the head, while type 2 fractures frequently go on to pseudarthrosis and ultimately require surgical correction.

Slide 82) What are the key anatomical observations here?

Slide 83) The spinous process of C2 is midline. The head and C1 are subluxed on C2. Can you see the cause of the subluxation on the film?

Slide 84) There is no connection between the visible dens ossicle and the body of C2. There are 2 possible causes. What are they and which one is most likely here?

Slide 85) This is an os odontoidium anomaly. There is hypoplasia of the C2 portion of the dens and hyperplasia of the terminal ossicle, which arises from the fourth occipital somite. The terminal ossicle is attached by fibrous tissue rather than bone and has become unstable.

Slide 86) title mid cervical spine no text

Slide 87) The axial plane is ideal for the evaluation of the bony vertebral ring. The size and shape of the spinal canal can best be evaluated in this view. The cervical facet joints, which are angled obliquely to the axial plane, are seen but are hard to evaluate fully. The entire length of the neural foramina is spread before us.

Slide 88) Remember that gradient echo axial MR views tend to cause an apparent thickening of the bone with artifactual narrowing of the foramina. The thinner the axial slices the more precise the definition of the neural foramina. The term “neural foramen” is really a misnomer. In actual fact the nerve roots leave the spine through a canal which has entrance and exit foramina. Symptom producing stenosis most commonly occurs at or near the entrance zone of this canal. That is not always the case. It is important to get into the habit of defining areas of stenosis in terms of which portion of the canal is narrowed. The treatment for exit zone stenosis may not be the same as for entrance zone narrowing.

Slide 89-90 no text

Slide 91) This patient has central canal as well as lateral and foraminal stenosis due to facet joint disease. There is a large synovial cyst filling the spinal canal. The bony hypertrophic spurs narrow the entire length of the foramen.

Slide 92) The sagittal plane is ideal for the evaluation of the alignment of the vertebra, the height of the disc spaces, the internal structure of the discs, and the existence of disc herniation and bony ridges. T2 weighted views are ideal because they silhouette the low signal posterior annuls against white water inside the thecal sac.

Slide 93) Coronal CT reformations are useful for the evaluation of the vertebral end plates and the uncinate processes. This patient has typical C5/6 spondylosis. The lateral projecting uncinate spurs are seen to advantage.

Slide 94) Sagittal reformatted CT is ideal for the evaluation of the articular processes. The entire surface of the facets can be seen on thin section reformations. The dense cortical bone of the facet is distinguishable from the medullary center of the articular pillar. Small indentations are common normal findings in the articular surfaces. Note the tiny bone fragment arising from the tip of the inferior articular process of C6. This may be an old fracture.

Slide 95) Oblique reformations are ideal for the evaluation of the neural foramina but are not generally done since the sagittal views nearly always provide the necessary information.

Slide 96) On good quality soft tissue oblique CT reformations, one can even identify a small amount of fat around the exiting nerve.

Slide 97) Lets review what we have covered so far. Here are a few quiz cases. What abnormal findings are obvious on this set of flexion – extension views?

Slide 98) Note first, the narrowed and degenerated C5/6 disc with retrolisthesis. This is a longstanding abnormality.

Slide 99) There is subluxation of C1 forward upon C2 in the flexed position, this reduces on extension. No fracture is identified on the routine films although a subtle fracture is very likely present where the transverse ligament attaches to the ring of C1.

Slide 100) Remember always to look at the edges of the film. Multiple cervical fractures are often found after serious trauma. Normal motion segments may separate the fractures as we see here.

Slide 101) Another somewhat subtler unknown

Slide 102) There are no fractures seen here. There is a question of widening of the space between the anterior arch of C1 and he dens. There is however, disruption of the interlaminar line.

Slide 103) The upward extension of a line drawn along the inner curvature of the C3 lamina will point directly to the posterior rim of the foramen magnum. The posterior lip of the foramen magnum is identified on radiographs as the point of intersection of the inner and outer table of the skull. This is marked in blue. The inner cortex of the posterior arch of the normal C1 ring should always fall on this line. In this case this line which is marked in yellow, is displaced forward. There are two possible diagnoses, which can account for this malposition. What are they?

Slide 104) Congenital shortness of the C1 ring is an uncommon anatomical variant. The distance between the anterior arch of C1 and the dens is normal but the lamina of C1 projects further forward of normal with a break in the interlaminar line. In this case the distance between the dens and the anterior arch of C1 is widened indicating subluxation of C1 on C2.

Slide 105) There is a very subtle abnormality here of great clinical importance. Just an aside while you look at the film. It is sometimes difficult to perform a true lateral of the C1-C2 area on an uncooperative patient. A simple trick is to have the technologist perform a true lateral view of the skull centered a bit lower than usual. This will project the C1 ring along the plane of the x ray beam.

Slide 106) If you looked very carefully you would notice that he tip of the dens projects above the top of the anterior arch of C1. This is nearly always abnormal. The dens is slightly tipped backwards. The only possible way for this to occur is for the ring of C1 or the transverse ligament to be broken, torn or eroded.

Slide 107) What abnormalities are visible here?

Slide 108) This young fellow was playing hockey and was check heavily into the boards. He immediately developed weakness in his legs and tingling in the fingers. The C5/6 disc is narrowed. There is no obvious injury here. The spinal canal is very small. It would never pass the pinky test.

Slide 109) Note on the MRI scan, the lesion in the central cord at the level of the degenerated disc. Contusion of the spinal cord is an unfortunately common occurrence in people with degenerative disc disease and very small spinal canals. Whenever there is disproportionately sever neurological injury with normal or relatively normal x rays, hyperextension injury of the spine with cord contusion is the likely diagnosis,

Slide 110) What are the likely diagnoses here?

Slide 111) There is dense bone ossification of the anterior spinal ligaments at multiple levels. This is the hallmark of the DISH syndrome. Superimposed upon the DISH changes is a fracture of the top of the fused anterior bone.

Slide 112) The accompanying MR scan shows the soft tissue ligamentous injury, which includes laceration of the intervertebral disc. Note the compression of the spinal cord between the lamina of C4 and the inferior portion of the C3 body.

Slide 113) There is an important although subtle finding on this frontal radiograph can you see it?

Slide 114) The distance between the spinous processes is widened. For this to occur, the interspinous ligament must be torn

Slide115 On the lateral view of another patient with a similar injury we note the compression fracture of the vertebral body, with widening of the interspinous space.

Slide 116) This is an easier case. What abnormalities do you see?

Slide 117) There is scoliosis concave to the right. The disc at C5/6 is asymmetrically narrowed and the nucleus pulposis is calcified. The lateral masses are of different heights. All this is explained if one makes the diagnosis of congenital failure of segmentation of the two vertebrae. There is fusion of the articular pillars on the right and more normal articular pillars on the left.

Slide 118) These are three different patients. What forest do you place them in?

Slide 119) They all have one thing in common and that is that they have diffuse degenerative disc disease at multiple levels with small anterior osteophytes and or ligamentous calcifications.

Slide 120) Both of these patients have had hyperextension injuries with ligamentous injury anteriorly. This has manifested itself as fracture and slight displacement of the anterior osteophytes. The differential diagnosis between degenerative calcification, osteophyte and fracture may be very subtle.

Slide 121) There is a subtle abnormality here, which is not of clinical importance. It is only important that the careful observer not be fooled while evaluating the film and diagnosing something that is not present.

Slide 122) when you evaluate the interlaminar line here, you notice that there is none at the C1 level. This is the hallmark of the incomplete C1 ring. This is a very common congenital lesion of little significance other than an occasional misdiagnosis as a fracture.

Slide 123) This last patient is an entire textbook of pathology. There has been an attempt at spinal fusion at two levels because of a diagnosis of myelopathy. The fusion is not solid. There is a halo of lucency adjacent to the grafts at both levels. Depending on how soon after surgery this film was done the diagnosis can be made of pseudarthrosis. It is critical that one always look at all of the film. In this case a large plaque of ossification of the posterior longitudinal ligament was missed.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download