1. Small Animal Neuroradiology: The Spine Lecture 1 – Radiography and Contrast Techniques, Anomalous Diseases
VCA 341 Fall 2011
Andrea Matthews, DVM, Dip ACVR
Assistant Professor of Radiology

2. Normal Anatomy Canine and feline vertebral formulas Cervical 7
Thoracic 13
Lumbar
Sacral
3 (fused)
Caudal
Variable
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3. Normal Anatomy – Cervical
C1 (or “atlas”)
Central arch and two wide horizontal wings perforated by transverse foramina
C2 (or “axis”)
Long, thin spinous process which overlaps the dorsal arch of C1
Odontoid process (dens) C6
Expanded transverse process ventrally
The spinous processes become more prominent from C4 caudally, with the spinous process of C7 being the largest. The disc space at C2-3 appears narrow compared to C3-4. On a lateral radiograph, the articular processes are positioned obliquely and superimposed over the intervertebral foramina and vertebral canal.
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4. Cervical Spine C1 C2 C3 C5
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5. Cervical Spine atlas C1 axis C2 C3 C5 VCA 341 – The Spine Matthews
TUSCVM

6. Normal Anatomy – Thoracic
Rib heads articulate with cranial aspect of corresponding vertebral bodies Spinous processes change direction from caudal angulation to cranial angulation at the anticlinal vertebra (usually T11) Accessory processes on last 4-5 thoracic vertebrae T10-11 intervertebral disc space is normally narrow
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7. Thoracic Spine T11 T10 Anticlinal vertebra
Anticlinal disc space is narrow normally
T11
Proximal ribs
T10
TUSCVM
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8. Normal Anatomy - Lumbar
Lumbar vertebral bodies are longer than thoracic vertebrae
Especially in cats.
Transverse processes are angled cranially, laterally and somewhat ventrally
Accessory processes (present on the first four vertebrae) can be especially large in cats
“Fuzzy” ventral margin of L3 and L4
Due to attachment of the diaphragmatic crura (especially in large dogs). }
Do not mistake for
mineralized intervertebral
disc material!
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9. Lumbar Spine
TUSCVM
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10. Thoracic Spine
Accessory process
TUSCVM
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11. Lumbar Spine L3 L4 Attachment for diaphragmatic crus
TUSCVM
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12. Sacral / Caudal Vertebra
Sacrum
Lumbosacral angulation can vary significantly between individuals
Changes with degree of flexion or extension
Caudal Vertebra
Formerly known as coccygeal vertebrae
Vary in number
Hemal arches ventrally
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13. Sacral / Caudal Vertebra
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14. Lumbosacral Junction Ilial wings Articular facet joint
TUSCVM
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15. Lumbosacral Junction Margins of the sacrum VCA 341 – The Spine
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TUCSVM

16. Typical Vertebra
Right and left pedicles form walls, body forms floor and lamina forms roof of vertebral canal
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17. Ligamentous Structures
From Veterinary Anatomy of Domestic Animals, 3rd Ed, Konig and Liebich
Konig and Liebich, Veterinary Anatomy of Domestic Animals, 3rd Ed
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18. Survey Radiography Lateral and ventrodorsal views
Adequate relaxation is required for good positioning
General anesthesia preferred
Exception: Suspected fracture and/or luxation
Can obtain lateral and horizontal beam
Collimation to improve quality
Collimate, pseudonarrowing
VCA 341 – The Spine
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19. Survey Radiography Lateral cervical radiograph Ventrodorsal cervical
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20. Survey Radiography Lateral thoracic radiograph VCA 341 – The Spine
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21. Survey Radiography Beware of “pseudonarrowing” of disc spaces
Artifactual narrowing due to divergence of x-rays
Collimate, pseudonarrowing
Kishigami, Y.et al. Vet Radiol Ultrasound 41, 9–18 (2000).
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22. Pseudonarrowing
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23. Radiography and Contrast Techniques
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24. Myelography Introduction of contrast into subarachnoid space
Water soluble, iodinated, non-ionic contrast media
Sites of injection
Cisterna magna
More likely to seizure
Difficult to get flow caudally in some cases
Lumbar (L5-6, L4-5)
Possible epidural leakage
More difficult technically
Fewer complications
Better flow of contrast typically
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25. Myelography Site for cervical injection Site for lumbar injection
Diaz, F. In Practice 27, (2005).
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26. Myelography Indications Contraindications
Neurologic signs with no lesion on survey rads
Multiple lesions seen on survey rads
Single lesion seen on survey rads not consistent with clinical signs
Abnormality on survey rads which needs further characterization
Contraindications
Inflammatory disease (meningitis)
Bleeding diatheses
Evidence of vertebral instability (could increase spinal cord damage)
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27. Normal Myelogram
Courtesy Dr. L. Pack
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28. Extradural Lesion Extruded intervertebral disc material L3 L3 L4
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29. Intradural/Extramedullary Lesion
Golf tee sign
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30. Intramedullary Lesion
Widening of spinal cord due to spinal cord tumor (glioma)
Courtesy Dr. L. Pack
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31. Anomalous Diseases
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32. Hemivertebra Failure of vertebral body to develop fully
Persistence of sagittal membrane (notochord)
Most commonly in thoracic spine
May have focal kyphosis
Often incidental finding
Bulldogs, Boston terrier and pugs (“screw-tailed” breeds)
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33. Hemivertebra
Butterfly vertebra
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TUCSVM

34. Block Vertebra Fusion of two or more adjacent vertebrae
Involve bodies, laminae and pedicles or entire vertebrae
Incomplete development of intervertebral disc
Can occur at any location in spine
Incidental
Differentiated from healing fractures, luxations, discospondylitis
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35. Block Vertebra
TUCSVM
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36. Transitional Vertebra
Vertebra at the junction between two spinal regions that assumes the characteristics of both regions
Thoracolumbar, lumbosacral and sacrocaudal junctions
Usually incidental findings
Important when identifying surgical site
Make positioning of VD pelvis difficult
Can be associated with lumbosacral instability
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37. Transitional Vertebra
Sacralization of L7
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38. Spina Bifida Part of general defect called Spinal Dysraphism Two types
Failure of neural arch to close during embryogenesis
Two types
Spina bifida occulta
No spinal cord or meningeal involvement
No clinical signs typically
Spina bifida manifesta
Protrusion of the meninges (meningocele) or meninges and spinal cord (meningomyelocele)
Associated clinical signs
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39. Anomalous Diseases Common in screw-tailed breeds
Bulldogs, Boston Terriers, Pugs, Manx cats
Failure of fusion of spinous processes
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40. Other Anomalies Scoliosis Lordosis Kyphosis
Lateral bowing as seen on a VD or DV view
Lordosis
Ventral bowing as seen on a lateral view
Kyphosis
Dorsal bowing as seen on a lateral view
Scoliosis (from Radiographic Interpretation for the Small Animal Clinician 2nd Ed)
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41. The End
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