What condition involves the inflammation of the sinuses in a horse's head?

The correct answer focuses on sinusitis, which specifically refers to the inflammation of the paranasal sinuses in the horse's head. This condition can arise due to various factors, including infections, allergies, dental issues, or other irritants. Symptoms of sinusitis in horses may include nasal discharge, facial swelling, coughing, and difficulty breathing, making it a distinct and identifiable problem within equine health.

Understanding the terminology is essential; other listed conditions refer to different areas of the body and types of inflammation. For instance, bronchitis affects the bronchial tubes in the lungs, colitis involves inflammation of the colon, and pneumonia is an infection of the lungs. Each of these conditions presents with symptoms and implications that differ from those associated with sinusitis. Therefore, sinusitis accurately describes the specific condition of sinus inflammation in horses.