Case 2. Ursus thibetanus Raffles, 1821
The cleaned skeleton of an adult female Asiatic black bear Ursus thibetanus was obtained by the third author. The bear died in 1994 in Zwartberg zoo, Genk, Belgium. Unfortunately, neither professional autopsy, nor radiographic examination was performed, and there was no information available regarding age or life history. Judged from the skeletal development, this animal was advanced in age. The skeleton is kept in the Natural History Museum Rotterdam (reg. no. 999000835).
Examination of the macerated skeleton
Skull. – The skull and dentition were almost completely normal. The canines were severely worn, as is normal in a zoo bear. No alveodental abscesses were apparent.
Forelimbs. – The scapulae, humeri, radii and ulnae showed signs of severe osteoarthrosis (Figs. 11 & 12). In most of the metacarpalia and carpalia and some of the phalanxes, marginal osteophytes were found. No erosive lesions were visible.
Fig. 11. Humeri of Ursus thibetanus (case 2) with severe osteoarthrosis (arrowheads showing marginal osteophytes).
Fig. 12. Proximal ends of the ulnae of Ursus thibetanus (case 2) with severe osteoarthrosis (arrowheads indicating marginal osteophytes).
Hindlimbs. – On the femora and tibiae impressive signs of osteoarthrosis were found (Fig. 13). Both knee joints showed severe signs of degeneration. On the patellae large marginal spurs were visible. The tarsalia and metatarsalia showed also degenerative features in the form of marginal osteophytes.
Cervical vertebrae. – Large nonmarginal syndesmophytes were found on the left ventral side of C5 and C6. Erosion of the vertebral endplate was found on the caudal endplate of C3, cranial and caudal endplate of C4, C5 and C6, and the cranial endplate of C7. Some signs of arthrosis of the zygapophyseal joints were found on all cervical vertebrae. Marginal osteophytes were found on C2 up to and including C7.
Thoracic vertebrae. – All thoracic vertebrae showed severe pathological changes. On all margins degenerative osteophytes were found. On the right ventral side of Th6 up to and including Th11 large nonmarginal new bone formation was found, possibly nonmarginal syndesmophytes. No ankylosis was observed between any of the thoracic vertebrae. Signs of arthrosis of the zygapophyseal joints were found in most of the thoracic vertebrae. Erosion of the vertebral endplate was mostly confined to the mid-thoracic vertebrae. On the 13th thoracic vertebrae, large nonmarginal syndesmophytes were found lipping with those on the 14th thoracic vertebra. This 14th thoracic vertebra was found completely fused with the first lumbar vertebra (Fig. 14).
Lumbar, sacral vertebrae and pelvis. – There was a complete fusion between the 14th thoracic and all lumbar vertebrae (Fig. 14). The new bone formation has fused the vertebrae on all sides. There was complete fusion in all zygapophyseal joints. The sacroiliac fusion was complete and symmetric. Between the 5th lumbar vertebra and the sacrum, impressive new bone formation (syndesmophytes) was found, without fusion of these syndesmophytes or of the zygapophyseal joints.
Fig. 14. Lower thoracic and lumbar vertebrae and pelvis/sacrum of Ursus thibetanus (case 2). Complete fusion of the vertebrae and (A) complete sacroiliac fusion. Spondyloarthropathy.
Comments on case 2next section
On the spine, osteophytes and syndesmophytes were found as features of degeneration (discarthrosis, spondylosis deformans) and spondyolarthropathy. Mixtaosteophytes were also found. Initial alternations of spondyloarthropathy are most usually found in the thoracolumbar and lumbosacral junctions, as in the case described here. The fusion of the sa-croiliac joints was complete. Most likely this case represents a combination of osteoarthrosis/discarthrosis and spondyloarthropathy of Reiter’s type or psoriatic arthritis.