Equine Spine Thorax

sihirlifil's version from 2017-11-25 22:21

Cervical Spine

Question Answer
How is horse positioned for spinal rads?Head extended, rested on support, neck straight, radiolucent head collar
How can we tell which vertebrae are where on radiographs?Do overlapping views. 2 & 6 are distinctive but easy to mistake 3,4,5. Use radiopaque marker to keep track with serial images
Centering points for cervical spinal radiographs1) Cranial at level of mid-vertebral body of axis (C2)
2) Mid-neck over C4
3) Cd neck over C6, just cranial to shoulders
Collimate: include cervical spine
Where in the neck does the beam have to be centered? Why?Near ventral/middle 3rd. Dorsal is where ligamentum nuchae & muscles are
For C6-T1: special considerations?Increase exposure, use grid (lots of muscle)
WHat does C6 look like?Large transverse processes (like toboggan) has cr & cd extensions
NORMAL physis of odontoid process of dens (C2)
NORMAL C1 & occipitoatlantal junction
What happened?
Nothing! NORMAL VARIANT: accessory process on C2
You radiograph an Arab horse and see this:
Subluxation of atlanto-occipital junction (white)
Due to malformation of C1 (yellow)
Not articulating with occipital condyles. C1 slipped ventrally, conjoined with C2 (Norm: )
What happened here? Result?
Subluxation of C2
Dens displaced dorsally (white)
Reduces width of spinal cord (black) = pressure = extremely painful!
How does the spine of a foal look normally?
What’s wrong with this foal?
Cervical vertebral malformation
Caudal epiphysis of C3 = enlarged (white = norm ventral margin cd epiphysis C2)
Congenital block vertebrae of C5-C7 (lack if IV disc spaces, fused spinous processes)
Arrow? what’s going on?
(ventral) Subuluxation of C4-C5
Sudden step down, lucent defects (lysis) suggestive of Osteomyelitis & infection either side of disk consistent with diskospondylitis (hematogenous infection can happen in foals)
Fracture of cranial articular facets
Arrows = what structure? Something to note?
Normal articular facets of C4-C7
It’s a SYNOVIAL joint = can get OA!
(US of articular facet from lateral neck, yellow arrows = cranial & caudal margins) what is the white arrow showing?
DJD irregular bone around lateral margin
Infection with areas of sclerosis (long arrow) of vertebral body of C6 surrounding osteolysis (short arrow)
Disruption of ventral floor = neuro deficits
What is the maximal sagittal diameter (MSD) of the vertebral canal?
What condition? How is the MSD?
Cervical vertebral malformation (CVM) a.k.a. Wobbler’s syndrome
Vertebral malalignment with severe compression of spinal cord & subluxation
Super narrow- new bone formation at caudal physis (overfed) --> profoundly ataxic
How does the spinal cord look? why? (myelogram)
Compressed at level of C4-C5 articulation, due to OA SUBSEQUENT TO CVM
True OA, new bone formation around joints (remodeling of facets)

Thoracic Spine

Question Answer
Technique: Grid?Yes
Technique: positionHorse standing square & straight, radiopaque markers should be placed ~2 vertebrae apart (above vertebrae) to assist in localization & vertebra ID
Technique: centerLevel of the tip of the spinous process in question (image dorsal spinous processes first, then can do bodies if worried)
Technique: collimationInclude tips of adjecent vertebrae
Most dorsal vertebra (tallest spinous process) is usually which one?T6 or T7
Anticlinal vertebra =T15 (mid thoracic spine)
For thoracic & lumbar bodies: points about technique?Center lower down
Look at articular facets, can do obliques across if suspect abnormality
NORMAL separate centers of ossification of spinous processes from T4-T10
Allow for growth in height at point of the withers
They are FRAGILE and can be peeled off (avulsion fractures)
How is the metal marker helpful?Allows accurate counting of spinous processes
Arrows? What can happen as a result?
Old fractures of the spinous processes of T5-T8 with displacement of the tips of T5 & T6
Callus formation of tips of T7 & T8
Lose blood supply --> sequestrum --> draining tract (fistulous withers)
Whats going on? sequela?
Focal area of lysis in cr aspect of spinous process of T5
Local discharge = fistulous withers (Brucella)
Kissing spines
Which 2 abnormalities present?
Left 2 arrows = OCLL of T12 & T13
Right 3 = Kissing spines ((source of lameness. can US, inject LA/steroids; radical tx = remove every 2nd process

Thoracolumbar Junction, Lumbosacral, & Pelvis

Question Answer
(How to orient yourself)Last pair of ribs go to T18
Can kissing spines happen at the TLJxn?Yep!
What’s going on?
Over-riding spinous processes from T13-T18 & OCLL (white arrows)
Structure at arrows?
Articular facet joints
How do these articular facets look?
Enlarged; remodeling around facets of L1-L2
This US image shows?
Remodelling around articular facets right L1-L2 (left side is normal)
In the loin region, what part of the spine can you see? why?Only tips of spinous processes (not whole thing) because of the bulk of the musculature (density obscures)
Overriding spinous processes of T17-T18 (have to resort to US to see)
What should you do before taking a LS exposure?Evacuate rectum!
Pelvis technique: position?Legs tied into flexed or frog-leg potision
DON’T WANT ANESTHESIA! fracture may displace if horse moves
A focal image of the hip joint can be taken with pelvis slightly tilted (US is better)
Special/more dangerous way to take a pelvic radiograph?Standing VD (xray machine ventral abdomen, pointing proximally & cd)
Need carefully sedated horse, xray machine highly vulnerable


Question Answer
How is it possible to get the whole thorax?Need minimum 3 but usually 4 overlapping areas ON EACH SIDE
Right side against detector = RIGHT lung
Left side against detector = LEFT lung
Technique for standing lateral thoraxFFD 1.5-2 meters, PLUS air gap to allow scattered radiation to miss the detector/film
(Don’t need gantry system, can rig machine to drip set)
Which region?
Which region?
Which region?
Which region?
((MUST include tips of caudal lung lobes: exercise-induced pulmonary hemorrhage)
This is a R lateral of a 10-week-old foal. CS: Incr respiratory effort, RR 36BPM, dyspnea, no fever. Lung crackles on auscultation. WBC & fibrinogen elevated. Why??
R equi infection (dx BAL cytology & culture)
ONLY VISIBLE ON LEFT LATERAL! Patchy alveolar infiltrate
Widespread mixed pulmonary infiltrate with noudles = Rhodococcus equi
Pleural effusion in caudoventral thorax
Almost horizontal line = junction of fluid/air (\US better to diagnose)
Severe collapse, air lying dorsal to relatively opaque collapsed lungs
Condition? whats the weird looking thing?Pneumothorax dorsal to bilateral collapsed lung lobes
Drainage tube in place
Intrapulmonary abscess in caudodorsal thorax
White arrow = cranial margin
Black arrowhead = fluid line in cavitated abscess
Exercise induced pulmonary hemorrhage
Focal increase in opacity in CAUDODORAL lung region
Obscures aorta
How does the cardiac silhouette look on radiographs?Only gross changes can be seen!
Arrows? Ultimate dx?
Megaesophagus in 6m.o. foal, secondary to pyloric stenosis