Or by dropping the feed from the mouth after partly chewing it

Or by dropping the feed from the mouth after partly chewing it

The eye on the side of the discharging nostril may have a peculiar appearance and look smaller than its fellow. There may be an enlargement, having the appearance of a bulging out of the bone over the part affected, between or below the eyes. The breath may be offensive, which indicates decomposition of the matter or bones or disease of the teeth. A diseased tooth is further indicated by the horse holding his head to one side when eating, or by dropping the feed from the mouth after partly chewing it. When the bones between the eyes, below the eyes, and above the back teeth of the upper jaw are tapped on, a hollow, drumlike sound is emitted, but if the sinus is filled with pus or contains a large tumor the sound emitted will be the same as if a solid substance were struck; by this means the sinus affected may be located in some instances. The hair may be rough over the affected part, or even the bone may be soft to the touch and the part give somewhat to pressure or leave an impression where it is pressed upon with the finger.

Fonte: Diseases of the Horse