m. collapse — includes failure of the maxilla to grow, as in achondroplastic dwarfism, or atrophy due to turbinate atrophy, as in atrophic rhinitis. The result is a dishing or depression of the face.
m. cyst — a cyst that occurs in young horses and causes sufficient distortion of the bone as to obstruct the nasal passage.
m. myositis — a localized myositis of unknown origin which occurs in young horses. It causes inability to eat or to suck the mare. The muscles of the cheeks are hard.
m. process — an embryonic fold which develops from the first visceral arch and expands to produce the rostral bones of the upper jaw.
m. sinusitis — infection in the maxillary sinus, often from an infected tooth. Causes local facial swelling and nasal discharge. See also malar abscess.
m. swelling — a unilateral swelling which is usually an indication of an osteomyelitis, as in actinomycosis of cattle, tooth-root abscess of dogs or sinusitis in horses. Bilateral swellings are characteristic of osteodystrophia fibrosa in dogs and horses.