Acta Veterinaria Scandinavica 2007, 49:39 http://www.actavetscand.com/content/49/1/39 and milliampere-seconds used depended upon the size of the vertebrae and varied between 50 and 60 kV and 10 and 20 mAs respectively. At least four exposures were taken of each dog covering the vertebral column from the first cervical (C1) to the first sacral (S1) vertebra. The total number of calcified discs and their location in the vertebral column were recorded according to earlier described methods [13,14]. Three degrees of calcification of the individual discs were noted and defined as follows (Figure 1): SLIGHT: - one or more calcified bodies with diameter less than 2 mm, or - calcification of part of the transitional zone between the nucleus pulposus and the annulus fibrosus, or - indistinct calcification of a larger part of the nucleus pul- posus MODERATE: - calcified bodies with diameter less than 2 mm and calci- fication of part of the transitional zone between the nucleus pulposus and the annulus fibrosus, or - distinct calcification of a larger part of the nucleus pul- posus, or - indistinct calcification of the entire nucleus pulposus tLdFhaiogtcehrurasracheliucrn1a(dTi5o)fgrvsateaprnhtedfbarrodamisnitzhaees(isDxe-ovyegenantroh-o.cl1ed0r,)vmicaalle(,Cs m7)otooththcoeaftifetdh Lateral radiograph from the seventh cervical (C7) to the fifth thoracic (T5) vertebra in a six-year-old, male, smoothcoated dachshund of standard size (Dog no. 10). Three interverte- bral discs; T1–2, T3–4 and T4–5, shows a 'severe', 'moderate' or 'slight' degree of calcification (arrows). SEVERE: - distinct calcification of the entire nucleus pulposus If there was doubt about calcification or the degree of cal- cification, additional radiographs were taken of the verte- bral section of current interest. Immediately after the radiographic examination, speci- mens for histological examination were collected by removing each intervertebral disc between the second cer- vical (C2) and first sacral (S1) vertebra in all of the 20 ver- tebral columns. With tissue forceps, a scalpel handle and no. 11 blade the discs were carefully separated from the adjacent vertebral body end plates (extremitas cranialis et caudalis) and removed. All specimens (520 discs) were fixed in 4% phosphate- buffered formaldehyde, pH 7.2. Subsequently the discs were dehydrated in ethanol, equilibrated in xylene and embedded in paraffin. Decalcifications of the specimens were not performed. The discs were sectioned transversely at about 5 µm and stained with hematoxilin-eosin and von Kossa, a method for demonstration of calcium [15]. During the preparation process all sections concerning 17 discs became incomplete and consequently these discs were regarded as withdrawals. By this, 503 discs were available for a final histopathologic examination by light microscopy. Three degrees of calcification of the individual discs were noted, and for each category, all findings might appear either separately or in combination with other lesions. The degrees of calcification were defined as follows: SLIGHT (Figure 2): - single or multiple foci of calcification occupying less than half of the area of the nucleus pulposus - single or multiple small foci of calcification within the annulus fibrosus MODERATE (Figure 3): - single or multiple foci of calcification occupying more than half, but not all, of the area of the nucleus pulposus - single or multiple medium size foci of calcification within the annulus fibrosus - thin calcified ring, continuous or discontinuous, either surrounding the nucleus pulposus or localised within the annulus fibrosus Page 3 of 7 (page number not for citation purposes)