Contributors: Patsy Whelehan

 Species: Feline   |   Classification: Techniques

Introduction Requirements Preparation Procedure Aftercare Outcomes Further Reading


  • Accurate centering is essential when radiographing any joint.
  • High definition film-screen combinations are required.
  • A grid is not necessary.
  • kV should not exceed about 50.
  • Close collimation is essential.
  • If general anesthesia is not used, then heavy sedation with analgesia is needed.
  • The film must include the whole joint, with soft tissues, must be correctly exposed and developed and free from movement blur and artifact.
  • The anatomical marker must be clearly visible, along with the patient's identification, the date, and the name of the hospital or practice.


  • An important diagnostic aid in determining the cause of a lameness arising from the shoulder.
  • Bony injury: fracture or dislocation Shoulder: luxation - traumatic.
  • Bony neoplasia or soft tissue neoplasia invading bone Synovial sarcoma.
  • Investigation of soft tissue injury.
  • Joint effusion, swelling .


  • Non-invasive.
  • Straightforward.


  • Poor positioning can make subtle pathology impossible to detect.
  • The presence of severe pain can make the procedure difficult in a conscious patient.

Time Required


  • Dependent upon the method of chemical restraint (GA or sedation).


  • 10 to 15 minutes, or longer, dependent upon skill of radiographer.

Decision Taking

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?

Choosing the right projections

Lateral: standard projection
  • Shows glenoid cavity and head of humerus.
  • Demonstrates joint space.
  • Shows soft tissue swelling and joint effusions.
  • Can show calcification in tendons.
Craniocaudal: second standard projection, or supplementary
  • Essential second view in cases of known or suspected fracture.
  • Usually necessary in cases of dislocation.



Other involvement

  • Radiographer, or Technician carrying out radiography.

Materials Required

Minimum equipment

  • X-ray machine.
  • Cassettes with high definition screens.
  • Processing facilities.
  • Immobilization and positioning aids: sandbags, foam wedges, tying tapes.
  • Protective clothing (lead-rubber aprons).

Ideal equipment

  • High output X-ray machine.
  • Rare earth high definition screens.
  • Automatic processing facilities.

Minimum consumables

  • X-ray film.
  • Pharmaceuticals for chemical restraint.



  • One to two competent people.
  • Sandbags.
  • Foam wedges.
  • Tying tapes.
  • Positioning trough.


Core Procedure

Step 1 - Lateral projection

  • Place the patient in lateral recumbency on the side to be examined and immobilize.
  • Use a sandbag to hold the contralateral limb out of the field caudally and dorsally .
  • Use a tie to distract the affected limb well cranially, and secure.
  • With foam wedges, pad under the elbow to ensure the humerus is parallel to the film.
    Locate by palpation of the lateral aspect of the shoulder joint space.
  • Center with a vertical beam directly through the joint space .
  • Collimate to include the entire glenoid cavity, the soft tissues of the joint, and the proximal third of the humerus .

Step 2 - Craniocaudal projection

  • Place the patient in dorsal recumbency in a trough and immobilize.
  • Rotate the thorax away from the affected side .
  • Using a tie, extend the affected limb as far cranially as possible and secure.
  • Adjust position of thorax and limb to ensure the joint is in the true craniocaudal position.
  • Center the vertical beam through the joint space by palpation of the lateral aspect.
  • Collimate to include the soft tissues of the joint and the proximal third of the humerus .

Step 3 - Cranioproximal-craniodistal (bicipital groove) projection

  • Place the patient in sternal recumbency .
  • Flex the shoulder and the elbow.
  • Abduct the radius slightly so that it does not lie beneath the shoulder.
  • Palpate the groove on the cranial aspect of the head of humerus and direct the beam tangentially through it.
  • Collimate closely.



Reasons for Treatment Failure

  • Inadequate sedation.
  • Poor technique: inaccurate positioning or centering, wrong exposure factors.
  • Poor processing.
  • Equipment failure.

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Allan G S (2000) Radiographic features of feline joint disease. Vet Clin North Am Small Anim Pract 30 (2), 281-302 PubMed.