A comparison of canine and avian skeletal and respiratory systems and diseases

Abstract

Utilizing comparative anatomy, we aim to expand anatomical knowledge of canine and avian species in those with basic understanding of the skeletal and respiratory systems. The canine is utilized as a model for comparison to establish general anatomical principles before introducing the evolutionary adaptations of the avian skeletal and respiratory systems, supporting the idea that form follows function. Additionally, variations in anatomy create a divergence in presentation, diagnosis, and treatment of various pathologies of these systems. The canine skeletal system is largely unfused, with many joints and flexibility, allowing efficient terrestrial locomotion and maneuverability. The avian skeletal system has many aspects of fusions in the vertebrae and appendages, providing rigidity that assist in flight stability and lowering mass. Canine respiration is bidirectional, requiring one inhale and one exhale for a full respiratory cycle. Avian respiration is unidirectional, requiring two inhales and two exhales for a full respiratory cycle, maximizing gas exchange for flight at altitudes with lower oxygen levels. Fractures cause problems in the skeleton's structural integrity, no matter the species. Canine rib fractures can be deadly, decreasing respiratory efficiency and increasing risk for secondary infections. Avian fractures impact the respiratory system in pneumatic bones, which often contain air sacs. Rupture of air sacs through fractures can increase risk of respiratory and bone infections, and often require surgical intervention. A fungal infection like aspergillosis primarily affects avian species, though it can present as sinonasal aspergillosis or disseminated aspergillosis in canines. Avian influenza (AI) affects both avians and canines, and can present as low or high pathogenicity in avian species. Generally, canines infected with AI have mild symptoms, though it can mutate in canines and establish a lineage of canine influenza.