Fractures

Acute fractures have hemorrhage with sharp bone edges; chronic fractures may have callus, fibrosis, or infection. Trauma (eg, environment, animal handling, electrocution) and nutritional considerations are major risk factors.

Osteomyelitis

Bacterial infection of bone. Secondary to trauma, sepsis, penetrating wounds.

Osteochondrosis, epiphysiolysis, apophysiolysis

Growth plates may be swollen. Joint lesions common on articular surfaces or growth plates of femur, tibia, humerus, ulna, vertebrae. Usually occurs after 10 weeks of age.

Metabolic bone diseases

Rickets, osteomalacia, osteopenia, osteoporosis caused by interactions of calcium (Ca), phosphorus (P), vitamin D, phytase. Swollen growth plates, soft bones, pathological fracture.

Nutrient excess or deficiency

Excess: Vitamin A, fluorine or distorted Ca:P ratios.

Deficiency: Ca, P, vitamin D, vitamin A, vitamin C, copper (Cu), manganese (Mn), zinc (Zn).

Joint infections (see the tables Common Bacterial Agents Associated With Lameness and Viral Agents That May Contribute to Lameness Expression or Ataxia)

Joint pain, swelling, fever. Abnormal synovial fluid is less viscous and may contain fibrin or exudates. Synovium may be thickened.

Trauma

Injuries may affect any musculoskeletal tissue.

Congenital

Malformations: Congenital hyperostosis, chondrodysplasia, arthrogryposis, dwarfism due to micronutrient deficiencies, toxicities, or genetics.