Equine Fetlock

sihirlifil's version from 2017-12-12 21:31


Question Answer
Which radiographic views are used?Dorso-palmer/plantar
High DP (D30PrDiP)
Lateromedial (LM)
Flexed LM
DMPLO for sesamoids
Dorsoproximo-Dorsodistal oblique (Skyline) of dorsal sagittal ridge (DPrDDiO)
How is the DP taken?Cassette palmar, parallel to pastern
Cassette holder on inside (behind)
Horizontal beam
How are the sesamoids related to the joint in FL vs HL?FL: sesamoid bases close to joint
HL: Bases overlap the joint
High DP (D30PrPaDiO): how is the projection taken? why?Beam: angled down 20* or 30*, coming from side
No superimposition of sesamoids on joint = joint space better exposed (sesamoids moved proximal)
How is LM view taken?Need to use different centering points depending on joint of interest (can't get good lat of DIP & MC-P joints at same time)
DIP: use block
DLPMO profiles the ___ sesamoisLateral
DMPLO profiles the ___ sesamoidMedial
DLPMO & DMPLO: markers where?LATERAL aspect of the limb!
Flexed lateromedial good for?Dorsodistal aspect of sagittal ridge Mc3 and articular margins of sesamoids
Moves sesamoids away from palmar aspect of Mc3
DPrDDiO: good for?Osteochondrosis & cyst-like lesions ((common in standard& thoroughbreds)
How is the DPrDDiO taken?Fetlock flexed
Beam tangential to dorsal aspect of the fetlock
CAREFUL person holding leg & cassette very close to beam!
Radiolucent lesion on the sagittal ridge (should have bump instead of dent)
NORMAL vascular channel in P1 (not a fracture!)
Can also see attachments for sesamoidean ligaments (2 radiolucent stripes)
NORMAL radiolucent area due to depression in distal palmar aspect of P2
Dont mistake for OCLL!
Conditions of the fetlockFractures
Osseus cyst-like lesions (OCCL)
Angular limb deformity (ALD)
Degenerative joint disease (DJD)
Fractures of the MC-P joint: most common locations?1: apical fracture, tip of sesamoid
2: apical prox third of bone
3: Midbody
4: Basilar at site of attachment Distal sesamoidean ligaments
Avulsion of palmar eminence of P1 (tear of short sesamoidean ligaments)
6: Palmar eminence of P1 (tear of distal sesamoidean lig)
7: OC frag of sagittal ridge distal Mc3
OC frag Dorsoprox P1 (ddx chip fracture)
Ddx for 5, 7, & 8?
Osteochondrosis fragments
Signs: no fracture line, can find bed, surrounded by cartilage all the way around
Non-displaced avulsion fracture of apical 3rd of proximal sesamoid
(raise heel, prevent hyperextension of fetlock- suspensory lig)
Avulsion fracture with proximal displacement of the fractured fragment (apical 3rd prox sesamoid)
(remove frag if <1/3)
(DLPMO) Small avulsion fragment off palmar eminence of prox phalanx, minimally displaced
What's wrong here? (2!)
Smooth, rounded, chronic fracture of proximal 3rd of lateral sesamoid
Oblique fissure fractures in Mc3 & involving articular surface of P1
Fractures: why is it important to hold off on pain relief?If they stand on it, joint could collapse
If still 3-legged lame 3 days later, re-radiograph (see fracture lines better b/c osteoclastic activity)
Fissure articulr non-displaced fracture of lateral condyle Mc3
Sclerotic line = overlap of fracture margins
What is this procedure?
Lag screw compression (pulls fragments closer together as bone heals)
Problem? what do you notice about the views?
Complete articular fracture Mc3 with Displacement of fracture on lat condyle
NOT VISIBLE ON LATERAL! Only on DP (mid) & DMPLO (right)
What kind of fracture? arrows?
Physeal! Complete Type I SH with dorsal displacement of the condyles
Arrows = normal physes of P1 & P2
Easily missed on DP view!
Osseous cyst-like lesion on distal Mc
Whats wrong with this foal? WHich view shows it best?(LM, DP, high DP)
Soft tissue swelling
High DP shows it best, proves that it's in Mc3 and not the sesamoid bone (shows large aperture, fluid gets into cyst, pressure effect painful)
Osteochondrosis of Mc3 sagittal ridge
OC palmar aspect P1
Left: medial eminence is normal, OC is on lateral eminence (see on right side image)
Radiographic signs of sesamoiditisIrregular outline to basilar & palmar aspect of sesamoid bones
Irregular new bone formation (entheseophytes)
Entheseophytes on apical abaxial aspect of lateral sesamoid, at site of attachment of medial br of suspensory lig (long arrow)
Soft tissue swelling
Left arrow?
Osteophyte on DPr P2
ST swelling = ringbone
Right top arrow? bottom?
(DLPMO) Entheseophyte reaction along PL aspect of P1, at attachment of oblique sesamoidean lig
Bottom: sidebone
Osteophyte formation (DiDM aspect of P1)
Traumatic exostosis (chronic)
Angular limb deformity (traumatic, resulting from physeal fracture with lateral displacement of body P1)
Marie's disease (Hypertrophic osteopathy)
How does Marie's disease look on radiographs?Periosteal reaction occurs at right angles to long bones, does NOT affect joints!!
Usually due to chronic thoracic disease e.g. heaves, COPD
Rarely due to abdominal pathology
NOT symmetrical as in dogs
NORMAL nutrient foramen through plantar cortex!
How do the metarsals differ from metacarpals?HL: 2 & 4 sit much further behind, not out to side
Head of Mt4 is much bigger (HL)
DLPMO & DMPLO: Which Carpals & Metacarpals articulate fully? Which don't?FULLY: 2nd Mc with 2nd carpal ('put 2 & 2 together')
Fracture of Mc2
Can cause compression of flexor tendon if callus expands axially
Problem? What happened to get the image on right? (DLPMO)
Chronic Mc4 fracture
Right = post-op, removed distal 2/3 (disrupts CMCJ)
Sclerosis at origin of suspensory lig on palmar Mc3 (have to scan tendons, see whats going on)
Right: Sclerosis & linear fissure fracture in medullary cavity Mt3 (origin of suspensory lig)
What happens with cortical fracture & fragment sequestration?Linear cortical bone sequestrum within radiolucent cavity (trauma)
Sclerotic reaction surrounding radiolucent cavity = involucrum, cortical defect with cloaca for discharge
(Smooth periosteal reaction on dorsal aspect Mt3)
Degloving injury! Causes cortical sequestrum

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Question Answer
Something to note about bovine footVestigial digits
Entheseophytes (axial aspects of P1s, where interdigital ligs attach)
Periarticular new bone formation
Which claw is more broad, M or L?Lateral
Problem? common cause? (DP & LM)
Comminuted fracture of mid-diaphysis of Mc3/4 in a calf (plaster cast is in place)
Result of calving jack injury (if from rope, may have compromised blood supply --> malunion)
Infection/cellulitis metatarsal region
Marked soft tissue swelling along whole length of Mt3/4
Gas pocekts on plantar aspect + abscess
Faint periosteal reaction plantar aspects cortices Mt3 & 4
Chronic cellulitis & periostitis with gross ST swelling, severe periosteal reaction along distal Mc3/4 & P1s
Joints are normal
Infectious osteoarthritis
Complete disruption of DIP of Medial claw
Joint space of DIP absent, lysis of abaxial & proximal surfaces of P3 + sublux
Large ST swelling
What's going on here?
Large rubber shoe on lateral claw to raise the hoof & prevent weight-bearing on damaged claw
Medial claw: infectious OA (complete disruption DIP joint, widened joint space & dorsal displacement of P3)
Tx of choice for infective DJD?Digit amputation

(Infective DJD of lateral DIP joint)

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