Small Animal Vertebral Column and Skull Radiography

Flashcards covering radiographic positioning, measurement sites, central ray locations, and diagnostic considerations for the small animal vertebral column and skull.

False narrowing of intervertebral disc spaces

An artifact caused by muscle spasm when general anesthesia is not used to achieve muscle relaxation during vertebral radiography.

Horizontal cross-table beam

An alternative radiographic method used for ventrodorsal views when a compromised patient must remain in lateral recumbency.

Lateral Cervical Vertebrae (Measurement)

Measured across the shoulder at the level of C6 to ensure adequate penetration of the caudal cervical vertebrae.

Cervical Vertebrae Routine (Central Ray)

Centered at the C3-C4 intervertebral space.

Cervical Vertebrae Routine (Borders)

From the base of the skull to the spine of the scapula (just past the shoulder joint).

Lateral Thoracic Vertebrae (Central Ray)

Centered at T6-T7 or the caudal border of the scapula.

Thoracic Vertebrae Routine (Borders)

From C7 to L1 inclusive (shoulder joint to past the origin of the last rib).

Thoracolumbar Vertebrae Routine (Central Ray)

Centered at the T13-L1 intervertebral space.

Thoracolumbar Vertebrae Routine (Borders)

From the xiphoid to just beyond the distal portion of the last rib.

Lumbar Vertebrae Routine (Measurement)

Measured at the level of L6-L7 for adequate penetration.

Lumbar Vertebrae Routine (Central Ray)

Centered at the level of L3-L4 (lateral) or L4 (ventrodorsal).

Lumbar Vertebrae Routine (Borders)

From T12 to S1 (xiphoid to greater trochanter).

Lumbosacral Vertebrae (Central Ray)

Calculated at the level of the lumbosacral junction, just caudal to the wings of the ilia.

Ventrodorsal Lumbosacral View (Angle)

The beam is angled at $20$ to $30$ degrees in a caudocranial direction.

Caudal Vertebrae (Borders)

Four or five vertebrae on either side of the area of interest, or the full tail.

Skull Radiography Challenges

Difficulty in imaging due to complicated anatomy, superimposition of structures, and variation in breed size and shape.

Dense shadows in skull imaging

Interference caused by the endotracheal tube, tongue, and pinnae that should be repositioned or removed when possible.

Lateral Skull (Measurement)

Measured at the highest point of the zygomatic arch at the center of the cranium.

Lateral Skull (Central Ray)

Centered at the lateral canthus of the eye, midway between the eye and ear.

Skull Survey (Borders)

From the tip of the nose to the occipital protuberance.

Dorsoventral/Ventrodorsal Skull (Measurement)

Measured at the highest point of the cranium just caudal to the lateral canthi.

Ventrodorsal Skull (Purpose)

Recommended for routine skull radiographs and specifically for evaluation of the nasal sinus.