odd-toed ungulate
oedema
olecranon tuberosity
onion heel shoe
onychomycosis
oral administration
origin (of muscle or ligament)
Orohippus
orthopaedics
ossification
ossifying periostitis of fourth tarsal bone
osteitis
osteoarthritis
osteoarthritis of the coffin joint
osteochondritis dissecans (OCD)
osteochondrosis
osteomyelitis
osteophyte
osteoporosis
outdoor rug
oval track
over at the knee
over-built
overreach boots
overreaching
Oxspring radiograph
