Preliminary Radiographic Protocols for Identifying Congenital Malformations of the Caudal Cervical Vertebrae

In 2014, a published study based on dissections and skeletal examinations noted that 19:50 Thoroughbred horses had a congenital malformation of the 6th cervical vertebra (C6). In addition, it was found that in those 19 Thoroughbred horses expressing a congenital malformation of C6, 9 displayed a concurrent congenital malformation of the 7th cervical vertebra (C7). In this study, 3 Thoroughbred horses and 1 Thoroughbred type were clinically examined; 3 were radiographed for limb abnormalities and 2:3 radiographed for the congenital malformation of C6 and C7 prior to euthanasia. Upon dissection, 3:4 expressed a congenital malformation of C6 with 2:3 displaying a concurrent CM of C7. These 2 horses were positively radiographed for the CM of C6 and C7 prior to dissection. The radiographs of C6 were taken in direct lateral orientation with 0 degree of elevation and revealed the absence of the caudal ventral tubercle (CVT) of C6. Re-positioning the horse’s forelimbs caudally with an outstretched neck, C7 was radiographed at a 30° oblique lateral angle in a cranial to caudal direction with 0 degree of elevation; the transverse process of C5 remained cranial to the beam. The caudal aspect of the plate was positioned medial the Cranial deep pectoral and rotated vertically to expand the field of view of the cervical vertebrae, whilst remaining perpendicular to the beam.