Ossicular necrosis, 1322 Osteochondritis dissecans (OCD), 279 , 302 clinical recognition, 1370 evidences, 1369 –1370 initial assessment/H&P, 1370 magnetic resonance imaging, 1371 f management/diagnostic testing, 1370 –1371 medial femoral condyle, 1370 f Osteogenic sarcomas, 286 , 302 Osteoid osteoma, 302 , 362 Osteolysis, 283 Osteomyelitis, 302 , 362 , 402 , 721 , 1359 antibiotic therapy, 1361 t clinical recognition, 1359 discharge/admission, clinical indications for, 1361 evidences, 1358 –1359 initial assessment/H&P, 1359 magnetic resonance imaging of, 1360 f management/diagnostic testing, 1359 –1361 periosteal activity, in distal fibula, 1360 f treatment goals, 1359 triage considerations, 1359 Osteosarcoma, 279 Otalgia See Ear pain Otitis externa, 389 –390 , 396 , 1329 –1330 , 1329 f–1330 f Otitis media (OM), 157 , 175 , 222 , 225 , 396 , 909 See also Acute otitis media (AOM) chronic/recurrent, 224 Otitis media with effusion (OME), 390 –392 , 1319 Otolaryngology, inner ear injury, 1115 –1116 Otorrhea, 392 Otoscopy, 138 Ottawa Ankle Rules (OARs), 265 , 1204 Ottawa Knee rules, 280 , 403 Out-of-hospital cardiac arrest (OHCA) incidence rate, 43 age-wise, 43 , 44 t