2010 Radiology Exam - Musculoskeletal Case 2

SIGNALMENT: 4 month old male alpaca

HISTORY: Ataxia, incoordination, weak front limbs

See images below. Click to enlarge.



  • Irregular bone production on the ventral aspect of the body of C7
  • Irregular endplates of T1 and C7
  • Body of T1 shortened, body of C7 also possibly shortened
  • Smoothly marginated mineral opacity projecting into ventral aspect of vertebral canal at the caudal aspect of C7
  • Step between C7 and T1


  • Compression fracture and subluxation at C7-T1 with remodeling/degenerative changes; the possible causes would be discospondylitis with pathologic fracture or traumatic fracture.


  • Ask for radiographic views centered on the lesion
  • After radiographic conclusions, reasonable recommendations included CT, MRI, work up for discospondylitits (blood culture, urine culture, US guided aspirate of lesion).


  • Most candidates did well at identifying lesion, even if thrown by species; they gave a fairly good description and reasonable conclusions. It was expected that while candidates might not be experienced with camelids, they would be expected to know how bone reacts to different disease and be able to apply that knowledge to other species.
  • Many candidates failed to ask for radiographs centered on lesion, and instead went straight to advanced imaging or concluded on findings from the non-centered view. If they asked for additional views, candidates generally received more points for a better description. Candidates also failed to consider more than one differential diagnosis, most stopped at discospondylitis. The candidates that received full credit considered discospondylitis with pathologic fracture as well as traumatic fracture because of shortened vertebral bodies.