In horses, osteosarcoma most commonly involves which bones?

In horses, osteosarcoma most commonly involves which bones?

• A. Femur
• B. Tibia
• C. Mandible and Maxilla
• D. Scapula

Answer: (C)

Osteosarcoma in horses tends to involve the facial bones, with the jaw bones being the most common site. Among horses, tumors arising in the mandible and maxilla are seen far more often than those in long bones like the femur or tibia, or in flat bones such as the scapula. This pattern makes the jaw bones the best answer because it reflects the species-specific tendency for equine osteosarcoma to present in the facial skeleton, often causing facial swelling and dental or nasal signs. In practice, if you see a horse with unilateral facial swelling or nasal discharge, jaw osteosarcoma should be high on the differential.

Osteosarcoma in horses tends to involve the facial bones, with the jaw bones being the most common site. Among horses, tumors arising in the mandible and maxilla are seen far more often than those in long bones like the femur or tibia, or in flat bones such as the scapula. This pattern makes the jaw bones the best answer because it reflects the species-specific tendency for equine osteosarcoma to present in the facial skeleton, often causing facial swelling and dental or nasal signs. In practice, if you see a horse with unilateral facial swelling or nasal discharge, jaw osteosarcoma should be high on the differential.