Radiographic Positioning in Dog - The Veterinary Site

Radiographic Positioning in Dog


RADIOGRAPHIC POSITIONING IN THE DOG

The Forelimb:

         The standard radiographic positions for the examination of joints will be described and illustrated.

The shoulder:

Positioning:
Caudo-cranial view
·      This is best position for imaging either the scapula or shoulder.
·      The animal is positioned on its back supported by handbags or a radiolucent trough.
·      The affected limb is drawn cranially fully extended and secured with the tie.
·      The thorax may need to be rotated slightly away from limb to be radiographed in order to prevent it being overlaid by thoracic wall.
·      For the shoulder joint the beam should be centered level with the acromian process, for the scapula it should be centered midway between the acromian and caudal level of scapula blade.



Lateral view:

The animal should be in lateral recumbency with the limb to be radiographed adjacent to the table.
The head and neck should be extended
Upper limb should be retracted caudally
Limb under examination should be drawn forward and ventrally to ensure the shoulder is not overlaid by the pectoral muscle and cervical spine.
The beam should be centered on the shoulder which can be located by palpating the lateral tuberosity and centering the beam level with the caudal to it.

THE HUMERUS

Positioning
Caudo-cranial view
·      The dog is positioned in dorsal recumbency
·      The foreleg to be radiographed is held in extension cranially, so that the humerus lies in the center of x-ray film.
·      The x-ray beam is centered over the mid-diaphysis of the humerus bone.
·      The cassette/x-ray film should be large enough and the beam collimated so as to include both proximal (shoulder) and distal (elbow joint).



Lateral view:
         The animal is restrained in lateral recumbency with the limb to be radiographed on lower side i.e. towards table top.
         The forelimb is pulled in extension, cranially.
         The cassette is placed beneath the humeral midshaft. Consequently the upper limb is flexed and retracted back towards the thorax, while the sternum elevated using the foam block.
         x-ray beam is directed vertically downward, centered through the mid diaphysis of the humerus bone

The elbow joint:

Positioning:
Cranio-caudal view
·      There are three methods for obtaining this view and each requires careful positioning to ensure that there is no rotation.
·      The animal may be positioned in sternal recumbency with the limb extended and held with ties.
·      The thorax may need to be slightly rotated towards the limb being radiographed and supported.
·      The beam is centered on the radio-humeral joint and angled approximately 15 degree cranio-caudal.







Lateral view:
·      The elbow may be radiographed either in flexion or extension.
·      The animal is placed in lateral recumbency with the upper leg drawn caudally and secured.
·      For an extended view the beam is then centered over the medial aspect of the elbow, it may be necessary to place a foam support under the olecranon to prevent rotation.
         For a flexed view the elbow is flexed as far as possible, care being taken not to push the elbow under the pectoral muscle of sternum.




The radius and ulna:

Craniocaudal View (CrCd)
Positioning:

·      The animal is restrained in sternal recumbency with the leg to be radiographed held in extension cranially.
·      The forearm region (i.e. radius and ulna) is centered over the x-ray film.
·      The head should be flexed to the contralateral side, i.e. away from the area of exposure.
·      The Xray beam is positioned perpendicularly on top, centered such as to pass through the mid-diaphysis of the radius bone. X-Ray exposure of long bones should always include the proximal and distal joints.
·      In this case, the elbow and carpal joints will also be included when making the radiographic exposure.




The carpus and metacarpus

Carnio-caudal view/Dorsal Palmar View:
·      The animal is placed in strunal  recumbencey  with the forelimb extended
·      The X-ray beam is positioned perpendicular on top, centered such as to pass through the middle of the dorsal surface of the carpus
·      The distal part of the fore arm (radius & ulna) and phalanges should also be included when making the exposure.



Medio-Lateral view :

The animal is positioned in lateral recumbency with the upper limb retracted caudally and secured with ties
         The X-ray beam is centered on carpus which is in the extended position at the medial aspect of the carpal joint.
         The carpus should be held in the flex position

Hind limb:

The Pelvis

Ventro-dorsal view:
·      The standard view of the assessment of pelvis and hips.
·      The animal is supported in dorsal recumbancy ensuring that there is no rotation about the longitudinal axis
·      Hind limbs are extended so that femora are parallel and rotated medially. when correctly position the hind feet will be slightly turned medially
·      It is also called ‘frog-legged’ view of pelvis for diagnosis of hip dysplasia.






Lateral view:
·      Animal place in lateral recumbancy
·      Ensure that pelvis is not rotated by placing padding between the hind limbs
·      Center the beam over the greater trochantor



The Femur :

Cranio-caudal view:

Positioning:


The animal is placed in dorsal recumbency. The hindleg of interest is pulled caudally, with the mid-femoral shaft centered over the cassette. The view should include both proximal (i.e. hip) joint as well as distal (i.e. stifle) joint. The XRay beam is directed perpendicularly downwards centered at the cranial aspect of mid-point of the femoral shaft

MedioLateral View (ML):
Positioning:
·      The animal is restrained in lateral recumbency with the leg to be radiographed positioned downwards towards the table top (i.e. in this position, the medial side of the femur is directed towards the x-ray beam).
·      The leg is held in extension and the x-ray film is placed beneath the mid-shaft of the femur bone.
·      The upper hindlegs should be flexed and retracted away from the site of exposure.
·      The x-ray beam is positioned perpendicularly on top, centered such as to pass through the centre of the medial aspect of the femoral shaft.
·      The hip and stifle joints should also be included in this exposure.



Stifile Joint:

Carino-caudal view:
·      Position the animal in dorsal recumbency , rotated slightly away from the side under examination.
·      Extend the limb caudally and secure centre the beam over the patella.
·      The view should include the distal femoral shaft as well as proximal part of tibia and fibula.

Medio-lateral view:
Animal is placed in leteral recumbancy with the limb to be radiographed down
Either abduct the upper limb and secure with ties so it does not over lay the stifle being radio graphed
Stifle should be in neutral position i.e. neither  flexed nor extended 
Center the beam over the distal femoral condoyle at the midpoint of the medial aspect of the stifle joint

The Tibia:

MedioLateral View (ML):
Positioning:
  • The animal is placed in lateral recumbency.
  • The hindleg of interest is placed towards the table.
  • The upper leg is flexed and retracted away from the site of exposure.
  • The leg area, i.e. the shaft of the tibia and fibulae are centered over the cassette.
  • The view should include the proximal joint, i.e. the stifle, as well as the distal joint, i.e. the hock
  • The x-ray beam is directed perpendicularly downwards centered at the mid-point of the medial aspect of the tibial shaft

The Hock:

Carnio-caudal (dorso-planter)
·      The animal should be supported in dorsal recumbancy and rotated away from the limb under investigation which is extended and held tightly
·      The beam is centered over the tibio-tarsal joint.


Lateral view
·      Animal place in lateral recumbancy with the limb beam radio graph down.
·      The upper limb is either abducted or drawn caudally or cranially and secured
·      Beam is centered on tibo-tarsal joint

The Thorax

Positioning:
Dorso ventral or Ventro Dorsal view:
·      The subject is placed in sternal recumbency with elbows symmetrically abducted and drawn forwarded,the head and neck are held down with sand bag.
·      The hind legs are flexed in normal crouching positioning.
·      The beam should be centered in the mid line at the level of caudal prominence of scapulae.
·      Beam should be collimated so as to include the thoracic inlet and diaphragm including the cranial abdomen. A right or left marker should be included on the film.



Lateral view:
         Subject should be placed in lateral recumbency with fore limb drawn forward and held by ties to avoid super in position of triceps muscle mass over the cranial lung field.
         The head and neck should be gently extended not flexed or over extended.
         The beam should be centered over the 5th rib or level with the caudal border of scapula and midway between the sternum and thoracic spine.
         A useful guide midway between the caudal border of scapula and the sternum .


Standing Lateral View

Positioning:
         The standing lateral view is preferably obtained for diagnosis of diaphragmatic hernia in the small animals. The animal is restrained in the standing position with the forelegs held upwards, so that the animal bears weight solely on the hind-legs. With the Xray beam centered horizontally and at mid thoracic region, a lateral radiograph is obtained.

The Vertebral Column:

The Spine (Cervical Region)
VentroDorsal View (VD)
Positioning:
  • The animal is positioned in dorsal recumbency with the head and neck in extension.
  • The forelegs are pulled caudally on either sides of the thorax.
  • The cassette is centered beneath the cervical area.
  • The x-ray beam is focused and centered over the ventral aspect of the mid-cervical area.
Lateral View

Positioning:

·      For the lateral view, the patient is placed in either left or right lateral recumbency, ensuring that the long axis of the skull is parallel to the tabletop.
·      A radiolucent foam cushion is placed under the mid neck region to ensure that the cervical and thoracic vertebrae are in the same plane; that is, the mid neck should not sag down toward the table.
·      The fore limbs are drawn caudally to prevent superimposition of the scapula on the caudal cervical region. Gentle traction is exerted between the forelimbs and the skull. The neck should not be rotated on its long axis.
·      On the finished radiograph, the transverse processes should be super imposed on another. The x-ray beam is centered on the mid cervical region and collimated to include the caudal skull and the first thoracic vertebra.
·      In large dogs an adequate lateral study of the neck may require two radiographs, one centered between the second and third cervical vertebrae and one centered between the fifth and sixth. In puppies, the cranial aspect of the spine of the second cervical vertebra may not be visible because it is incompletely formed.


VentroDorsal View (VD):

Positioning:
For the ventrodorsal view, the animal is placed in dorsal recumbency with the forelimbs drawn cranially. The x-ray beam is centered over the area of interest. Sedation is required to ensure relaxation.

Lumbar Vertebrae:

Lateral View.



Positioning:
         For the lateral view, the animal is placed in lateral recumbency with the mid lumbar vertebrae supported on a radiolucent foam cushion to maintain them on the same plane as the thoracic vertebrae. The spine should not be rotated on its long axis, and the transverse processes on each side should over lie one another. To ensure that the hindlimbs are parallel to one another and that there is no rotation of the spine, a foam pad is placed between the femurs.
VentroDorsal View (VD):






Positioning:
         The ventro dorsal view is made with the animal in dorsal recumbency, without rotation, and with the x-ray beam centered over the area of interest. If the animal is in pain, the limbs can be flexed in the “frog leg” position.



Sacral and Caudal Vertebrae:

Positioning:
·      The sacrum is usually included on views of the lumbar region.
·      The coccygeal vertebrae can be studied on conventional lateral and ventro dorsal views.
 The Abdomen
Positioning
Ventro-dorsal view 
·      Animal should be positioned in dorsal recumbency
·      Forelimb should be drawn cranially and tied
·      Beam should be centered over mid abdomen at the level of the umbilicus
·      For larger animal two films may be required, one for the cranial and other for caudal abdomen

Lateral View:


Positioning:
This may be either left or right lateral
         Position animal in lateral recumbency on chosen side
         Ensure the hind limbs are drawn caudally and fore limbs are drawn cranially secured and tied.
         Beam should be centered over mid abdomen-may way between the umbilicus and the lumber spine
         N.B this is about 1/3rd of the way between the ventral and dorsal skin surfaces For the larger animals 2 films may be required

The skull:

VentroDorsal View (VD)

Positioning:

         The animal is restrained in dorsal recumbency. The forelimbs are pulled caudally and to the sides. The head is centered in extension such that the hard palate should be parallel to the cassette and the beam is focused and centered at a mid-point between the eyes and ears on the midline.

Lateral View:

Positioning:
The animal is restrained in lateral recumbency, with the head centered over the cassette. The beam is focused and centered midway between the eye and ear dorsal to the zygomatic arch. The jaws should be opened if the temporo mandibular joints are the region of interest.

The larynx and pharynx:

Lateral View:

Positioning:
·      The animal is restrained in lateral recumbency.
·      The forelimbs are pulled caudally and to the sides.
·      The head is slightly flexed and the laryngopharyngeal area is centered over the cassette.
·      The beam is focused and centered over the laryngopharyngeal area.

The maxilla:

DorsoVentral View (Intra-oral Film Placement)
Positioning:
  • The animal is restrained in sternal recumbency, with the forelegs flexed to the sides.
  • The head is head cranially in extension so that the hard-palate lies parallel to the table top; an intra-oral cassette is placed in the animal’s mouth.
  • The x-ray beam is focused and centered at a mid-point between the eyes and ears on the midline. This position also facilitates examination of the maxillary nasal turbinates.
The mandible:

VentroDorsal View (VD)
Positioning:
·      The animal is restrained in dorsal recumbency, with the forelegs flexed to the sides.
·      The head is head cranially in extension so that the hard-palate lies parallel to the film; an intra-oral cassette is placed in the animal’s mouth.
·      The x-ray beam is focused and centered at a mid-point between the eyes and ears on the midline.
·      The ventro dorsal position used with an intra oral film placement facilitates demonstration of the mandibular incisor teeth.
Radiographic Positioning in Dog Radiographic Positioning in Dog Reviewed by Admin on 18 March Rating: 5

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