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Normal RadiographicAnatomy of the Spinal

ColumnSarah Tibbs, BVetMed

Radiography of the Spine

z Anatomy is complexz Many structures overlap complicating

interpretationz Because of beam divergence the edges of

film are effected by obliquityz Radiographic interpretation is

compromised by poor positioning

Radiography of the Spinez Always take orthogonal views lateral and

ventrodorsal (VD)z Add oblique views if necessaryz Consider dynamic views (extended and flexed)

in the cervical and lumbo-sacral regionsz Image each region separately, with the beam

centered over the middle of that regionz Image certain areas with more collimation (i.e.

caudal cervical, thoracolumbar, lumbo-sacral)

Positioning

z Vertebral column mustbe parallel to the tabletop

z The transverse processof the vertebrae shouldbe perpendicular to thetable

z Proper patient positioning is CRITICALz Proper positioning requires anesthesia, tiesfor the limbs and sponge wedgesz Intervertebral disc spaces must beperpendicular to the table top (not oblique)

Vertebral Anatomyz Example here is a

cervical vertebraz Think

z

Lamina as the roof z Pedicles as the wallsz Body as the floor

z Vertebral appearancevaries somewhat byregion, but basic partsare the same

How to Count the CervicalVertebrae

6 754

321

z Landmarksz Atlas C1z Axis C2z C6 with large transverse processes

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How to Count the ThoracicVertebrae

z Landmarks

z T1 is actually just caudal to the first rib headsz T13 is the one with the last rib heads

1

1312

71098

11

65432

L1L2 L3

C7C6

How to Count the LumbarVertebrae

z Landmarksz Use the sacrum to help you find L7 and then count

backwardsz Or find T13 and count forwards

43

76

5

21T13T12

Sacrum

General Spinal Anatomy

1. Body2. Vertebral endplates3. Lamina4. Spinous process5. Transverse

processes6. Cranial articular

process7. Caudal articular

process

1

2

34

5

6

7

General Spinal Anatomy

General Spinal Anatomy

Articular facet joint space

Spinal canal

Intervertebral disc space

Intervertebral foramen

1. Cranial articularprocess

2. Caudal articularprocess

3. Intervertebral discspace

4. Body5. Endplates6. Spinous process7. Transverse processes8. Pedicles

1

2

3

4

5 67

8

General Spinal Anatomy

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General Spinal Anatomy Cervical Spinez Positioning

z head extendedz front limbs pulledcaudallyz wedge undermid-cervical region

Lateral Cervical Spine Positioning in Cervical Spine

Well positioned

Poorly positioned

VD Cervical Spine Cervical Spinez Seven vertebrae with

variable structurez C1 or atlas

z wide wingsz C2 or axis

z long thin dorsalspinous process

z dens with specialligaments

z No disc between C1-C2

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Cervical Spinez C3-C7 similar in shape

z C6 has expanded transverseprocessesz Intervertebral disc spaces at

C2-3 and C7-T1 are relativelynarrow *

**

Thoracic Spinez Positioning

z front limbs pulledcranially

z hind limbs pulledcaudally

z wedge under sternum

Lateral Thoracic Spine VD Thoracic Spine

Thoracic spinez Thirteen vertebrae uniform in shapez Variable dorsal spinous processesz Anticlinal vertebra T 11 *z Articular facet conformation changes at T10-11z Intervertebral disc space narrowest at T10-11

*

Lumbar Spinez Positioning

z front limbs pulledcranially

z

hind limbs pulledcaudally

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Lateral Lumbar Spine VD Lumbar Spine

Lumbar spinez Seven lumbar vertebraez Accessory processz Cranioventrally angled transverse processesz L3* and L4* site of attachment of diaphragmatic crura

* *

Feline Differences

z Curvature of spinez Shape of vertebral bodiesz Very prominent accessory process

Canine

Myelogramz A special procedure to evaluate the spinal cord,

when survey radiography is inconclusivez Aqueous non ionic iodinated contrast media is

injected into the subarachnoid spacez Standard lateral and VD views, as well as

oblique VDs are obtained of the area of interest

Herniated disc T13 L1

Clinical Correlation

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Spinal Column Fracture andLuxation

Spinal Column Subluxation andVertebral body fracture

Discospondylitis Spondylosis and Articular FacetOsteoarthitis

13.5 y old Golden

Mineralized Disc Material(IVDD- Intervertebral Disc Disease) Vertebral Anomalies

Block VertebraeButterfly Vertebra

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Aplastic Dens

Normal