Equine Appendicular Radiology

Nancy E. Love DVM, Dip.ACVR

Getting Started

• Knowledge of normal anatomy is PARAMOUNT!

• Knowledge of radiographic conventions is necessary

• Consistency is your friend• Learning this now will make life in the

clinic (and ultimately practice) soooo much easier!

Radiographic PositioningNaming the Views

• Can be confusing – Take the time to understand or equine

radiology will remain frustrating and difficult to understand

• YOU SHOULD BE ABLE TO: – IDE�NTIFY THE VIEW– DESCRIBE HOW IT WAS POSITIONED– IDENTIFY MEDIAL AND LATERAL BORDERS

• and where markers should be located

Radiographic PositioningNaming the Views

• ALL radiographs are named using the direction of the beam as it leaves the x-ray machine ---> passes through the patient ---> reaches the film

• There is a convention for extremities– Proximal to and including the radiocarpal and tibiotarsal

joints - use the terms CRANIAL and CAUDAL– From the carpus and tarsus distal to the radiocarpal and

tibiotarsal joints use the terms DORSAL and PALMAR (forelimb) or PLANTAR (hindlimb)

– PROXIMAL and DISTAL are also used when describing direction on the extremity

Radiographic PositioningForelimb

ForelimbShoulder 1 view LatElbow 2 views CrCd, LatCarpus 5 views DP, Lat, Flex Lat, DLO, DMO

ShoulderShoulderLateral viewLateral view

(Medial to lateral)(Medial to lateral)

ElbowElbowCC or CC or CrCdCrCd viewview(Cranial to caudal)(Cranial to caudal)

ElbowElbowLateral viewLateral view

(Medial to lateral)(Medial to lateral)

Lateral Medial

Marker is LATERAL

Accessory carpal bone

CarpusCarpusDP viewDP view

(Dorsal to (Dorsal to PalmarPalmar))

AnatomyLateral - Accessory carpal bone

CarpusCarpusLateral viewLateral view

(Lateral to Medial)(Lateral to Medial)

Marker is DORSAL

CarpusCarpusFlexed Lateral ViewFlexed Lateral View

(Lateral to Medial)(Lateral to Medial)

Intermediate carpal boneRadial carpal bone

Marker is DORSAL

AnatomyIntermediate carpal bone is more proximal

than radial carpal bone

Medial Lateral

Marker INCORRECTShould be at LATERAL aspect of limb (palmar)

60º off dorsal OR

30º off lateral

Anatomy

Lateral - Fourth carpal bone and MC IV have a “stairstep” appearance- Accessory carpal bone is NOT superimposed with the carpus

MCIV

C4

Accessory

CarpusCarpusDLO viewDLO view

((Dorsolateral Dorsolateral -- palmaromedial palmaromedial oblique)oblique)

MedialLateral

C2

MCII

Accessory

CarpusCarpusDMO ViewDMO View

((Dorsomedial Dorsomedial -- palmarolateral palmarolateral oblique)

Marker is LATERAL

60º off dorsal OR

30º off medial

oblique)

AnatomyMedial - Second carpal bone and MC II are superimposedAccessory carpal bone is superimposed with the carpus

Radiographic PositioningHindlimb

HindlimbHip Requires anesthesiaStifle 3 views CdCr, Lat, DMOHock 4 views DP, Lat, DLO, DMO

StifleStifleCC or CC or CdCrCdCr viewview(Caudal to Cranial)(Caudal to Cranial)

Lateral Medial

PatellaMedial tibial eminence

AnatomyLateral - Patella, FibulaMedial - Medial tibial eminence is larger

StifleStifleLateral viewLateral view

(Lateral to Medial)(Lateral to Medial)

Cassette is too low in this example. You must really push cassette high into flank!

Tarsus Tarsus (Hock)(Hock)DP viewDP view

(Dorsal to plantar)(Dorsal to plantar)

Lateral Medial

Marker is LATERAL

Calcaneus

AnatomyLateral - Calcaneus

Tarsus Tarsus (Hock)(Hock)Lateral viewLateral view

(Lateral to Medial)(Lateral to Medial)

Marker is DORSAL

Tarsus Tarsus (Hock)(Hock)DLO viewDLO view

((DorsolateralDorsolateral -- plantaromedialplantaromedial oblique)oblique)

Medial Lateral

60º off dorsal OR

30º off lateral

Marker is LATERAL

Lateral - Fourth tarsal bone and MC IV have a “stairstep” appearance- Calcaneus is NOT superimposed with the tarsus

Medial - Medial trochlea does NOT have a distal “hook”

“Stairstep” at T4 & MT IV

Calcaneus

Anatomy

MedialLateral

60º off dorsal OR

30º off medial

Marker is LATERAL

Medial - Second tarsal bone and MT II superimposedLateral - Large “hook” distal aspect of lateral trochlea

Lateraltrochlea

No “stairstep” between T1/T2 & MTII

Tarsus Tarsus (Hock)(Hock)DMO viewDMO view

((DorsomedialDorsomedial -- plantarolateralplantarolateral oblique)oblique)

Anatomy

Radiographic PositioningEither Limb

Either Limb

Metacarpus 4 views DP, Lat, DLO, DMOFetlock 5 views DP, Lat, flex lat, DLO, DMOPastern 4 views DP, Lat, DLO, DMOFoot (P3) 2 views DP, LatNavicular bone 5 views 60ºDP, Lat, 0ºDP, 30ºDP, DP-DDO

Metatarsus 4 views DP, Lat, DLO, DMO

MetacarpophalangealMetacarpophalangeal Joint (Fetlock)Joint (Fetlock)DPDP

(Dorsal to (Dorsal to palmarpalmar))

Marker is LATERAL

Metacarpophalangeal Metacarpophalangeal Joint (Fetlock)Joint (Fetlock)LateralLateral

(Lateral to Medial)(Lateral to Medial)

Marker is DORSAL

MetacarpophalangealMetacarpophalangeal Joint (Fetlock)Joint (Fetlock)Flexed LateralFlexed Lateral

(Lateral to Medial)(Lateral to Medial)

Flexed lateral views are typically made for the forelimbs ONLY

Sagittal ridgeMarker is DORSAL

AnatomyThe sagittal ridge is less opaque and more dorsally

located than the medial and lateral condyles

MetacarpophalangealMetacarpophalangeal Joint (Fetlock)Joint (Fetlock)DLODLO

((DorsolateralDorsolateral to to palmaromedialpalmaromedial oblique)oblique)

Medial Lateral

Marker INCORRECTShould be at LATERAL aspect of limb (palmar)

35º from dorsal OR55º from lateral

Lateral Medial

Marker is LATERAL

35º from dorsal OR

55º from medial

MetacarpophalangealMetacarpophalangeal Joint (Fetlock)Joint (Fetlock)DMODMO

((DorsomedialDorsomedial to to palmarolateralpalmarolateral oblique)oblique)

Lateral

Accessory carpal bone

Medial

MetacarpophalangealMetacarpophalangeal BonesBonesDPDP

Dorsal to Dorsal to palmarpalmar

Study is positioned the same way forMetatarsophalangeal bones

Metacarpophalangeal Metacarpophalangeal BonesBonesLateralLateral

Lateral to medialLateral to medial

Study is positioned the same way for Metatarsophalangeal bones

MetacarpophalangealMetacarpophalangeal BonesBonesDLODLO

((DorsolateralDorsolateral toto palmaromedialpalmaromedial oblique)“Stairstep” betweenC4 and MC IV - has tobe a DLO view

LateralMedial

oblique)

Study is positioned the same way forMetatarsophalangeal bones

MetacarpophalangealMetacarpophalangeal BonesBonesDMODMO

((DorsomedialDorsomedial toto palmarolateralpalmarolateral oblique)NO Stairstep” betweenC2 and MC II - has tobe a DMO view

MedialLateral

oblique)

Study is positioned the same way forMetatarsophalangeal bones

Distal Phalanx and Distal Phalanx and Navicular Navicular BoneBone60º DP60º DP

(Dorsal to (Dorsal to palmarpalmar oblique)oblique)

This view is also used for the 60º DP of the navicular bone. Increased collimation and a darker technique is required.

Distal Phalanx andDistal Phalanx and NavicularNavicular BoneBoneLateralLateral

(Lateral to medial)(Lateral to medial)

Distal Phalanx andDistal Phalanx and NavicularNavicular BoneBone30 30 -- 45º DP45º DP

Upright pedal viewUpright pedal view

NavicularNavicular BoneBoneSkylineSkyline

((DorsoproximalDorsoproximal to to palmarodistalpalmarodistal oblique)oblique)

Flexor eminence

“Wing” of P3

Generally move the heel to the back edge of the cassette holder