Computed tomographic and gross anatomy of the head of the blue-fronted Amazon parrot (Amazona aestiva)

The blue-fronted Amazon parrot is an extremely popular pet bird in Brazil. These birds are commonly raised in captivity and are often seen in veterinary practice. Modern imaging modalities such as computed tomography (CT), which had not been widely used in wild and exotic bird medicine until recently, are now becoming more popular due to wider availability and higher diagnostic accuracy. However, proper interpretation of tomographic findings requires species-specific anatomical references. Studies investigating normal tomographic anatomy of parrots are scarce. This study set out to describe the normal anatomy of the head of the blue-fronted amazon parrot (Amazona aestiva) using conventional CT. Anatomical descriptions may contribute to future comparative morphology studies and assist in clinical practice. The head of the blue-fronted Amazon parrot is structurally similar to other bird species. Major differences detected were are as follows: size and position of nasal conchae (long middle concha and small caudal concha located at the end of the nasal cavity), infraorbital sinus aperture located on the lateral aspect of the nasal cavity, presence of a nasopharyngeal duct connecting the nasal and oral cavities, longer infraorbital sinus with a larger number of caudal compartments and paraglossum with morphological features unique to psittacines. High-quality CT images were vital for identification and detailed description of most head structures. Multiplanar reconstruction was a useful tool for complete visualization of the head. However, conventional CT images were not good enough for visualization of the inner ear and related structures, as well the paratympanic sinus.