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Equine Tarsus

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sihirlifil's version from 2017-11-20 15:25

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Question Answer
Which views are used for the equine tarsus?Lateromedial (LM)
Dorsoplantar (DPl)
DLPlMO
DMPlLO
Plantaroproximal-plantarodistal oblique (PlPrPlDiO skyline sustentaculum tali)
How is the LM taken?Limb must be vertical, not overextended, Mt3 perpendicular to the ground
Center at tarsocrural joint, diverging beam going downhill (joints not horizontally oriented- oblique from lat-med 10* downhill)
Clear joint spaces!!
How should the sustentaculum tali look on an LM view?More radiolucent with sclerotic rim
Separate centers of ossification in foal to be aware ofTuber calcaneous
Lateral malleolus of tibia
Medial malleolus of tibia
Physes: distal tibia, proximal calcaneus
How do the cuboidal bones look in a foal?Rounded, wider joint spaces
How is the DP view taken?Metatarsus perpendicular to ground
Center: Proximal intertarsal (centrodistal) joint
How is the PLPlMO taken?Center: intertarsal joints
Beam angles 60* (Mt don’t sit on the side of Mt3, more around the back, so beam has to come around further)
Hints for recognizing the PLPlMOCalcaneous hangs out the side
Can see T4 (double decker)
Lateral splint doesn’t fully articulate!!!
Name the joints Yellow: Talocentral (prox intertarsal- medial)
Green: Calcaneoquatral (prox intertarsal-lateral)
Red: Centrodistal (distal intertarsal)
White: tarsometatarsal
How is the DMPlLO taken?Center: intertarsal joints
Beam angles 60*
Hints for recognizing the DMPLlLOParrot beak = lateral trochlear ridge of talus
1st & 2nd TBs FULLY ARTICULATE with Mt2
Calcaneous superimposed, foreshortened. Can see sustentaculum tali profiled
Which views are these? arrows?
Left: LM view, Medial ridge of trochlea (normal radiolucent depression = yellow)
Right: DMPlLO view, Lateral ridge of trochlea
How is the PlPrPlDiO taken?
Radiographic signs of osteochondrosisFlattening of the articular surface
Subchondral bone defect
Sclerotic rim/margin to the defect
Mineralized flap/large fragment = joint mice
**OC sites in the tarsusDistal intermediate ridge of tibia (DIRT lesion)
Lateral trochlear ridge of talus
Medial trochlear ridge of talus
Lateral & medial tibial malleoli
(Medial tubercle of talus)
OC on DIRT
Usually best seen on DMPlLO view
Large OC fragment separated from distal intermediate ridge. Semicircular depression in tibia = origin of fragment
Why should small OC fragments be removed?Can absorb nutrients from synovial fluid & grow into joint rats
OCD
Large radiolucent defect on lateral trochlear ridge of talus
OCD
Distal tip of lat trochlear ridge of talus sharp & horizontal, OC fragment separated distally
OC of medial trochlear ridge of talus with large ST swelling
OA: Low spavin (Tarsometatarsal joint)
Soft tissue swelling, new bone formation (yellow), remodeled tarsal bones (red), narrowed joint space (light blue)
Eventually arthrodesis (animal will no longer be lame, no pain once fused)
Arrows? what’s the difference between the 2 images?
OA of the centrodistal joint = Seat of spavin
Left: subchondral lysis along dorsomedial joint articulation = active disease
Right: indistinct joint space, sclerosis, more chronic reaction
Problem? how would the horse present?
OA of centrodistal joint
Horse isn’t lame (arthrodesed)
OA of the talocentral joint = High spavin
Indistinct talocentral joint space (sclerosis) = more chronic reaction
Incomplete ossification of cuboidal bones: causes?Immature (<330d), dysmature (born at term but not of gestational term age, e.g. mare had placentitis), or twins
Incomplete ossification of cuboidal bones: Radiographic signsWider joint spaces
TBs smaller, rounder than normal
Fragile TBs
If not supported: progressively deform, eventually fracture, DJD follows. Damage irreparable if severe
(can happen in carpal bones too)
Incomplete ossification of cuboidal bones in dysmature newborn foal
TBs smaller, rounder<be>Wedging dorsally of CT or 3rd TB
Extrustion of TB dorsally
Incomplete ossification of cuboidal bones
Severe: loss of definition of 2 distal rows of tarsus (sickle shape to plantar aspect & collapse of hock, TB3 not visible)
Fractures dorsal to CT bone (red)
Wedging of CT a/o TB3
Osteomyelitis
Circular lytic area in proximal calcaneous, marked sclerosis in adjacent areas
(Due to puncture wound. check for cortical fragments- can sequester)
Osteomyelitis
Mineral frag & defect in skin suggests wound
(scan for cellulities, see if bursa intact)
Avulsion fracture of lateral malleolus
Fracture of calcaneous, kicked on point of hock
Large ST swelling encircling calcaneous
Radiolucent defect on plantarolateral aspect of calcaneous
Chip fractures visible in adjacent ST
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