American College of Veterinary Surgeons Dr. Chris Wood BSc, DVM (Dist), MS
DACVS (Small Animal)

For vets and technicians · Local draft

Radiographic positioning library

Open TPLO planning views or choose a fracture region for positioning, matching radiographs and image checks. Coordinate new planning images with the surgical service.

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Choose a region

TPLO planning: positioning + radiographs →

Fracture imaging reference

Radius / ulna

Minimum pair: Mediolateral + craniocaudal

Calibration ball + side marker on EVERY radiograph.

Normal dog examples. These show the projection and anatomy. Some atlas frames only partly show adjacent joints; use the coverage and image checks below for fracture studies. Include a calibration ball in every patient view, including when the atlas example has none.

VIEW 1

Mediolateral (side view)

PositioningMediolateral positioning drawing for the dog radius / ulna, from Coulson with Lewis (2002), Figure 40, printed page 18; original beam-centre mark preserved.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 40, p. 18.
Normal atlas radiographNormal dog atlas radiograph: mediolateral radius / ulna, Coulson with Lewis (2002), Figure 39, printed page 18; matched to positioning Figure 40.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 39, p. 18.
  • Place the patient in lateral recumbency with the affected side nearest the detector. Support the forearm in a comfortable position away from the thorax.
  • Keep the opposite forelimb clear. Use foam to support the limb without twisting the fracture.

VIEW 2

Craniocaudal (front view)

PositioningCraniocaudal positioning drawing for the dog radius / ulna, from Coulson with Lewis (2002), Figure 43, printed page 20; original beam-centre mark preserved.View full screen ⤢
Normal dog · CraniocaudalCoulson with Lewis (2002), Fig. 43, p. 20.
Normal atlas radiographNormal dog atlas radiograph: craniocaudal radius / ulna, Coulson with Lewis (2002), Figure 42, printed page 20; matched to positioning Figure 43.View full screen ⤢
Normal dog · CraniocaudalCoulson with Lewis (2002), Fig. 42, p. 20.
  • If tolerated, use sternal recumbency with the affected forelimb supported cranially on the detector. Keep the carpus flat and the forearm straight.
  • If that position is unsafe, coordinate a supported horizontal-beam alternative with the imaging team.

Beam centre and coverage

Centre over the middle of the radius/ulna. Include the entire radius and ulna, elbow and carpus, with surrounding soft tissues. An elbow-only or wrist-only view does not show the whole fracture region.

Check the images before sending

  • Calibration ball visible in every radiograph.
  • Two different projections, rather than two slightly rotated lateral images.
  • Elbow and carpus included without cutting off either end of the bones.
  • On the frontal view, assess rotation at both elbow and carpus; record any limitation caused by the injury.

Check patient ID, side marker, sharp cortical detail and soft-tissue exposure on both views. Send the original images with acquisition limitations noted.

Sources for radius / ulna

Coulson with Lewis, An Atlas of Interpretative Radiographic Anatomy of the Dog & Cat (2002). Dog pp 18-21, Figs 39-44 (PDF 28-31); cat pp 367-368 (PDF 377-378).

UF: elbow and antebrachium positioning plus the common acquisition references below. Normal alignment is a quality target where the injury permits, not a reason to force an injured limb.

Fracture imaging reference

Tibia / fibula

Minimum pair: Mediolateral + frontal (CrCd or CdCr)

Calibration ball + side marker on EVERY radiograph.

Normal dog examples. These show the projection and anatomy. Some atlas frames only partly show adjacent joints; use the coverage and image checks below for fracture studies. Include a calibration ball in every patient view, including when the atlas example has none.

VIEW 1

Mediolateral (side view)

PositioningMediolateral positioning drawing for the dog tibia / fibula, from Coulson with Lewis (2002), Figure 146, printed page 84; original beam-centre mark preserved.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 146, p. 84.
Normal atlas radiographNormal dog atlas radiograph: mediolateral tibia / fibula, Coulson with Lewis (2002), Figure 145, printed page 84; matched to positioning Figure 146.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 145, p. 84.
  • Use lateral recumbency with the affected side nearest the detector. Move the opposite hindlimb clear of the tibia.
  • Support the tibia parallel to the detector, with stifle and hock resting comfortably. Avoid imposing TPLO planning angles on a fracture patient.

VIEW 2

Frontal (craniocaudal or caudocranial)

PositioningCaudocranial positioning drawing for the dog tibia / fibula, from Coulson with Lewis (2002), Figure 149, printed page 86; original beam-centre mark preserved.View full screen ⤢
Normal dog · CaudocranialCoulson with Lewis (2002), Fig. 149, p. 86.
Normal atlas radiographNormal dog atlas radiograph: caudocranial tibia / fibula, Coulson with Lewis (2002), Figure 148, printed page 86; matched to positioning Figure 149.View full screen ⤢
Normal dog · CaudocranialCoulson with Lewis (2002), Fig. 148, p. 86.
  • Choose the projection and supported recumbency that the patient can safely tolerate. Dorsal recumbency can provide a CrCd view; a CdCr approach is an alternative.
  • Align the tibia with the detector. A horizontal beam may help when repositioning is limited; coordinate the equipment and setup.

Beam centre and coverage

Centre over the tibial shaft for the whole-bone study. Include the entire tibia and fibula, stifle and hock, with surrounding soft tissues. Add joint-centred views if joint detail is needed.

Check the images before sending

  • Calibration ball visible in every radiograph.
  • Stifle and hock are present in both projections.
  • Assess femoral-condyle superimposition on the lateral and patellar centring on the frontal view where injury permits.
  • Displaced fragments may have different rotation; do not manipulate them to recreate a normal atlas image.

Check patient ID, side marker, sharp cortical detail and soft-tissue exposure on both views. Send the original images with acquisition limitations noted.

Sources for tibia / fibula

Coulson with Lewis, An Atlas of Interpretative Radiographic Anatomy of the Dog & Cat (2002). Dog pp 84-87, Figs 145-150 (PDF 94-97); cat pp 406-407 (PDF 416-417).

Mauragis & Berry: stifle and crus plus the common acquisition references below. Normal alignment is a quality target where the injury permits, not a reason to force an injured limb.

Fracture imaging reference

Femur

Minimum pair: Mediolateral + craniocaudal

Calibration ball + side marker on EVERY radiograph.

Normal dog examples. These show the projection and anatomy. Some atlas frames only partly show adjacent joints; use the coverage and image checks below for fracture studies. Include a calibration ball in every patient view, including when the atlas example has none.

VIEW 1

Mediolateral (side view)

PositioningMediolateral positioning drawing for the dog femur, from Coulson with Lewis (2002), Figure 125, printed page 74; original beam-centre mark preserved.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 125, p. 74.
Normal atlas radiographNormal dog atlas radiograph: mediolateral femur, Coulson with Lewis (2002), Figure 124, printed page 74; matched to positioning Figure 125.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 124, p. 74.
  • Use lateral recumbency with the affected side toward the detector. Move the opposite hindlimb out of the femoral field.
  • Support the patient and limb so the femur is as parallel to the detector as safely possible. Do not use traction to overcome pain or fragment displacement.

VIEW 2

Craniocaudal (front view)

PositioningCraniocaudal positioning drawing for the dog femur, from Coulson with Lewis (2002), Figure 128, printed page 76; original beam-centre mark preserved.View full screen ⤢
Normal dog · CraniocaudalCoulson with Lewis (2002), Fig. 128, p. 76.
Normal atlas radiographNormal dog atlas radiograph: craniocaudal femur, Coulson with Lewis (2002), Figure 127, printed page 76; matched to positioning Figure 128.View full screen ⤢
Normal dog · CraniocaudalCoulson with Lewis (2002), Fig. 127, p. 76.
  • Use a supported dorsal or slightly oblique body position to bring the femur into a frontal projection. Keep the hip and stifle in the image.
  • Adjust patient support and detector orientation rather than forcing the injured limb into full extension. Coordinate an alternative if a true frontal view cannot be obtained.

Beam centre and coverage

Centre over the femoral shaft, between the hip and stifle. Include the entire femur, hip and stifle, with surrounding soft tissues. The full proximal femur must be visible rather than hidden behind the opposite limb.

Check the images before sending

  • Calibration ball visible in every radiograph.
  • Femoral head/neck and both ends of the femur are included.
  • Check condylar superimposition on the lateral and patellar position on the frontal image, recognizing fracture displacement.
  • The femur is not severely foreshortened or obscured by the opposite limb.

Check patient ID, side marker, sharp cortical detail and soft-tissue exposure on both views. Send the original images with acquisition limitations noted.

Sources for femur

Coulson with Lewis, An Atlas of Interpretative Radiographic Anatomy of the Dog & Cat (2002). Dog pp 74-77, Figs 124-129 (PDF 84-87); cat pp 400-403 (PDF 410-413).

Merck: general musculoskeletal positioning plus the common acquisition references below. Normal alignment is a quality target where the injury permits, not a reason to force an injured limb.

Fracture imaging reference

Humerus

Minimum pair: Mediolateral + frontal (CrCd or CdCr)

Calibration ball + side marker on EVERY radiograph.

Normal dog examples. These show the projection and anatomy. Some atlas frames only partly show adjacent joints; use the coverage and image checks below for fracture studies. Include a calibration ball in every patient view, including when the atlas example has none.

VIEW 1

Mediolateral (side view)

PositioningMediolateral positioning drawing for the dog humerus, from Coulson with Lewis (2002), Figure 15, printed page 6; original beam-centre mark preserved.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 15, p. 6.
Normal atlas radiographNormal dog atlas radiograph: mediolateral humerus, Coulson with Lewis (2002), Figure 14, printed page 6; matched to positioning Figure 15.View full screen ⤢
Normal dog · MediolateralCoulson with Lewis (2002), Fig. 14, p. 6.
  • Use lateral recumbency with the affected side toward the detector. Support the humerus away from the thorax as safely tolerated.
  • Keep the opposite forelimb and sternum clear of the region of interest. Use padding to limit obliquity without twisting the injured limb.

VIEW 2

Frontal (craniocaudal or caudocranial)

PositioningCraniocaudal positioning drawing for the dog humerus, from Coulson with Lewis (2002), Figure 18, printed page 8; original beam-centre mark preserved.View full screen ⤢
Normal dog · CraniocaudalCoulson with Lewis (2002), Fig. 18, p. 8.
Normal atlas radiographNormal dog atlas radiograph: craniocaudal humerus, Coulson with Lewis (2002), Figure 17, printed page 8; matched to positioning Figure 18.View full screen ⤢
Normal dog · CraniocaudalCoulson with Lewis (2002), Fig. 17, p. 8.
  • Use a supported body position that presents the humerus in a frontal projection. The atlas includes both CrCd and CdCr examples.
  • Keep shoulder and elbow within the field. If the thorax obscures the shaft or the limb cannot be moved safely, coordinate a different setup.

Beam centre and coverage

Centre over the humeral shaft for the whole-bone study. Include the entire humerus, shoulder and elbow, with surrounding soft tissues. A routine shoulder or elbow study alone is insufficient for a shaft fracture.

Check the images before sending

  • Calibration ball visible in every radiograph.
  • Humeral head/shoulder and distal humerus/elbow are included.
  • The shaft is visible without avoidable overlap from the chest or opposite forelimb.
  • Check both views for additional fracture lines or fissures; do not assume a simple pattern from one image.

Check patient ID, side marker, sharp cortical detail and soft-tissue exposure on both views. Send the original images with acquisition limitations noted.

Sources for humerus

Coulson with Lewis, An Atlas of Interpretative Radiographic Anatomy of the Dog & Cat (2002). Dog pp 6-10, Figs 14-21 (PDF 16-20); cat pp 362-363 (PDF 372-373).

UF: humerus positioning plus the common acquisition references below. Normal alignment is a quality target where the injury permits, not a reason to force an injured limb.

Fracture imaging reference

Distal humerus / T-Y fracture

Required imaging: Full-humerus orthogonal views, including shoulder and elbow. The focused elbow pair below adds joint detail.

Calibration ball + side marker on EVERY radiograph.

Normal dog examples. These show the projection and anatomy. Some atlas frames only partly show adjacent joints; use the coverage and image checks below for fracture studies. These focused elbow examples supplement the full-humerus views. Include a calibration ball in every patient view, including when the atlas example has none.

VIEW 1

Elbow-centred mediolateral

PositioningExtended mediolateral elbow positioning drawing for the dog distal humerus / t-y reference, from Coulson with Lewis (2002), Figure 23, printed page 11; original beam-centre mark preserved.View full screen ⤢
Normal dog · Extended mediolateral elbowCoulson with Lewis (2002), Fig. 23, p. 11.

This shows a normal extended elbow. Do not force extension in a fracture patient.

Normal atlas radiographNormal dog atlas radiograph: extended mediolateral elbow distal humerus / t-y reference, Coulson with Lewis (2002), Figure 22, printed page 11; matched to positioning Figure 23.View full screen ⤢
Normal dog · Extended mediolateral elbowCoulson with Lewis (2002), Fig. 22, p. 11.
  • Use lateral recumbency with the affected elbow toward the detector. Support the forelimb in the position tolerated by the patient.
  • Keep the opposite limb clear. Avoid routine forced flexion, extension or stress views of an unstable painful elbow.

VIEW 2

Elbow-centred craniocaudal

PositioningCraniocaudal elbow positioning drawing for the dog distal humerus / t-y reference, from Coulson with Lewis (2002), Figure 32, printed page 15; original beam-centre mark preserved.View full screen ⤢
Normal dog · Craniocaudal elbowCoulson with Lewis (2002), Fig. 32, p. 15.
Normal atlas radiographNormal dog atlas radiograph: craniocaudal elbow distal humerus / t-y reference, Coulson with Lewis (2002), Figure 31, printed page 15; matched to positioning Figure 32.View full screen ⤢
Normal dog · Craniocaudal elbowCoulson with Lewis (2002), Fig. 31, p. 15.
  • If safely achievable, use supported sternal recumbency with the elbow and distal humerus on the detector.
  • Use the intact proximal and distal anatomy to assess rotation; a displaced articular fracture will not reproduce normal symmetry. Coordinate a horizontal-beam alternative if needed.

Beam centre and coverage

Centre the focused pair over the humeral condylar / elbow region. For focused joint detail, include the distal third of the humerus and proximal third of the radius/ulna with all soft tissues. Also obtain full-humerus orthogonal coverage including the shoulder for fracture assessment.

Check the images before sending

  • Calibration ball visible in every radiograph.
  • The complete distal humeral articular region and both epicondylar areas are visible.
  • Normal alignment checks help identify rotation, but displacement may prevent superimposition; do not force fragments to match.
  • Discuss additional obliques or CT with the surgical service if the articular fracture pattern remains unclear. These are case-specific additions.

Check patient ID, side marker, sharp cortical detail and soft-tissue exposure on both views. Send the original images with acquisition limitations noted.

Sources for distal humerus / t-y fracture

Coulson with Lewis, An Atlas of Interpretative Radiographic Anatomy of the Dog & Cat (2002). Dog elbow pp 11-17, Figs 22-38 (PDF 21-27); cat pp 364-366 (PDF 374-376). These are normal-anatomy examples, not a T/Y fracture protocol.

UF: elbow positioning plus the common acquisition references below. Normal alignment is a quality target where the injury permits, not a reason to force an injured limb.

Fracture imaging reference

Metacarpus / metatarsus

Minimum pair: Mediolateral + frontal paw view

Calibration ball + side marker on EVERY radiograph.

Normal dog examples. These show the projection and anatomy. Some atlas frames only partly show adjacent joints; use the coverage and image checks below for fracture studies. Include a calibration ball in every patient view, including when the atlas example has none.

VIEW 1

Mediolateral (side view)

PositioningMediolateral manus positioning drawing for the dog metacarpus / forepaw, from Coulson with Lewis (2002), Figure 59, printed page 28; original beam-centre mark preserved.View full screen ⤢
Normal dog · Forepaw · Mediolateral manusCoulson with Lewis (2002), Fig. 59, p. 28.
Normal atlas radiographNormal dog atlas radiograph: mediolateral manus metacarpus / forepaw, Coulson with Lewis (2002), Figure 58, printed page 28; matched to positioning Figure 59.View full screen ⤢
Normal dog · Forepaw · Mediolateral manusCoulson with Lewis (2002), Fig. 58, p. 28.
PositioningMediolateral metatarsus and phalanges positioning drawing for the dog metatarsus / hind paw, from Coulson with Lewis (2002), Figure 172, printed page 96; original beam-centre mark preserved.View full screen ⤢
Normal dog · Hindpaw · Mediolateral metatarsus and phalangesCoulson with Lewis (2002), Fig. 172, p. 96.
Normal atlas radiographNormal dog atlas radiograph: mediolateral metatarsus and phalanges metatarsus / hind paw, Coulson with Lewis (2002), Figure 171, printed page 96; matched to positioning Figure 172.View full screen ⤢
Normal dog · Hindpaw · Mediolateral metatarsus and phalangesCoulson with Lewis (2002), Fig. 171, p. 96.
  • Place the affected paw on its side and support the limb. Keep the opposite limb outside the field.
  • Keep the paw close to the detector without forcing damaged digits to spread or the fracture to straighten.

VIEW 2

Frontal paw view

PositioningDorsopalmar manus positioning drawing for the dog metacarpus / forepaw, from Coulson with Lewis (2002), Figure 56, printed page 26; original beam-centre mark preserved.View full screen ⤢
Normal dog · Forepaw · Dorsopalmar manusCoulson with Lewis (2002), Fig. 56, p. 26.
Normal atlas radiographNormal dog atlas radiograph: dorsopalmar manus metacarpus / forepaw, Coulson with Lewis (2002), Figure 55, printed page 26; matched to positioning Figure 56.View full screen ⤢
Normal dog · Forepaw · Dorsopalmar manusCoulson with Lewis (2002), Fig. 55, p. 26.
PositioningPlantarodorsal metatarsus and phalanges positioning drawing for the dog metatarsus / hind paw, from Coulson with Lewis (2002), Figure 169, printed page 94; original beam-centre mark preserved.View full screen ⤢
Normal dog · Hindpaw · Plantarodorsal metatarsus and phalangesCoulson with Lewis (2002), Fig. 169, p. 94.
Normal atlas radiographNormal dog atlas radiograph: plantarodorsal metatarsus and phalanges metatarsus / hind paw, Coulson with Lewis (2002), Figure 168, printed page 94; matched to positioning Figure 169.View full screen ⤢
Normal dog · Hindpaw · Plantarodorsal metatarsus and phalangesCoulson with Lewis (2002), Fig. 168, p. 94.
  • Forepaw: dorsopalmar. Hind paw: dorsoplantar or plantarodorsal, according to the safely achievable setup.
  • Support the paw flat to the detector and centre over the affected metacarpal/metatarsal region. Identify each injured bone and digit in the report.

Beam centre and coverage

Centre over the metacarpal or metatarsal region of interest. Include the full metacarpal/metatarsal bones from carpus/tarsus through the toes, including surrounding soft tissues and both ends of the injured bones.

Check the images before sending

  • Calibration ball visible in every radiograph.
  • The proximal bases, distal heads and relevant joints are not cut off.
  • Lateral paw views normally superimpose several bones. Check whether each suspected fracture is actually visible.
  • If overlap hides the fracture, coordinate supplemental oblique or focused digit views; do not treat a single lateral as adequate separation of every digit.

Check patient ID, side marker, sharp cortical detail and soft-tissue exposure on both views. Send the original images with acquisition limitations noted.

Sources for metacarpus / metatarsus

Coulson with Lewis, An Atlas of Interpretative Radiographic Anatomy of the Dog & Cat (2002). Dog manus pp 26-29 (PDF 36-39), hind paw pp 94-97 (PDF 104-107); cat manus pp 369-370 (PDF 379-380), hind paw pp 408-411 (PDF 418-421).

UF: carpus and manus; UF: tarsus and pes plus the common acquisition references below. Normal alignment is a quality target where the injury permits, not a reason to force an injured limb.

For every fracture study

  • Calibration ball + side marker on EVERY radiograph.
  • Two orthogonal views: image the same region in perpendicular projections. Include the full injured bone and adjacent joints.
  • Support the patient: use appropriate positioning aids and the clinic's radiation-safety procedures. Keep hands out of the primary beam; minimize manual restraint.
  • Plan before repeating: use a calibration ball on every view. Agree opposite-limb comparison, focused joint views or CT with the surgical service.
  • Send originals: include both views, date/time, side and any positioning limits. A photograph of a screen loses information.
Reference scope and common sources

This is a general veterinary imaging reference in local review. It is not an approved Chris-specific protocol for every fracture type. The surgery team confirms case-specific planning needs.

Coulson with Lewis, An Atlas of Interpretative Radiographic Anatomy of the Dog & Cat (Blackwell Science, 2002), introduction pp ix-x (PDF 7-8), is primarily a normal-anatomy atlas. Its positioning drawings and beam-centre symbols support the view references; it explicitly excludes a comprehensive positioning manual. Selected original positioning drawings and their matching normal-dog radiographs from the supplied atlas are paired beside each view, with figure and page credits. The radiographs illustrate normal anatomy and projection; the separate fracture coverage checks still apply. Patient stability and pain determine what positioning is safe.

Sources checked 18 October 2026. Per-region atlas page and figure references are given above.