Contributors: Justin Goggin, Patsy Whelehan
Species: Canine | Classification: Techniques
- A high resolution film-screen combination is required.
- A grid is not required.
- kV should not exceed about 60.
- Soft tissues should be included.
- General anesthesia or heavy sedation is required.
- The film should be correctly exposed and developed, and free from movement blur and artefact.
- The anatomical marker must be clearly visible, along with the patient's identification, the date, and the name of the hospital or practice.
- Evaluation of pain/disease localized to region.
- → Fracture.
- → Angular limb deformity .
- → Other bony conditions, eg panosteitis Panosteitis , hypertrophic osteodystrophy, etc.
- → Neoplasia.
- → Infection/osteomyelitis.
- Readily available.
- Dependent upon the method of chemical restraint (GA or sedation).
- 10-15 min or longer, dependent upon skill of radiographer.
Criteria for choosing test
Is the examination appropriate?
- Can you make the diagnosis without it?
- Can it tell you what you need to know?
- Will your management be affected by the radiological findings?
- Standard projection.
- Standard projection.
- Two orthogonal views always necessary.
- Always include the joint above and the joint below.
- Radiographer or Veterinary Nurse/Technician carrying out radiography.
- X-ray machine.
- Cassettes with high resolution screens.
- Processing facilities.
- Immobilization and positioning aids: sandbags, foam wedges, cloth tape or rope.
- Film labelling system.
- Protective clothing (lead-rubber aprons), gloves, thyroid shields.
- High output X-ray machine.
- Rare Earth high resolution screens.
- Automatic processing facilities.
- Film ID camera.
- ID card, tape.
- X-ray film.
- Pharmaceuticals for chemical restraint.
- 1-2 competent people.
- Foam wedges.
- Cloth tape or rope for restraint.
Step 1 - Lateral
- Position the patient in lateral recumbency on the side to be examined and immobilize.
- Use padding under the shoulder and carpus as necessary, to ensure that the radius and ulna are parallel to the film and in a lateral position .
- Check that both the elbow and the carpus are in the true lateral position.
- Secure the limb at the carpus.
- Center with a vertical beam at mid-shaft level.
- Collimate to include both the antebrachio-carpal joint and the elbow, and the skin surfaces on the cranial and caudal aspects .
For angular limb deformity the beam should extend at least to the metacarpus, and the opposite should be radiographed for comparison
Step 2 - Craniocaudal
- Place the patient in sternal recumbency.
- Extend the affected limb as far cranially as possible and secure .
If the elbow and shoulder are not in full extension it will be very difficult to maintain an unrotated craniocaudal position of the radius and ulna.
- Place the thin end of a 15° foam wedge between the elbow and the film. This will facilitate in achieving the true craniocaudal position.
- Rotate the limb until the point of the elbow is palpable beneath the middle of the cranial aspect, ie until the elbow is in a true craniocaudal position.
To prevent the elbow from slipping laterally, place padding at the lateral aspect, with a heavy sandbag lateral to that.
Positioning both hindlimbs to the side opposite the affected forelimb will help to achieve accurate positioning.
- Secure the limb at the carpus if necessary, but in the case of angular limb deformity it is better to secure at the elbow and let the distal limb lie naturally on the film.
- Center mid-shaft.
- Collimate to include both joints (and as far as the metacarpals in the case of angular limb deformity), and the skin surfaces laterally and medially .
Reasons for Treatment Failure
- Failure to obtain two orthogonal views, (incomplete study).
- Inadequate sedation.
- Poor technique: inaccurate positioning or centring, wrong exposure factors, failure to label film.
The most common positioning problem is rotation in the craniocaudal position.
- Follow the tips to ensure that this does not happen.
- Poor processing.
- Equipment failure.