Xanthomas, 465 , 636 Xerotic eczema, 433 Y Yale Observation Score, 196 Yellow fever, 844 Yellow, tan/brown papules, 638 –639 , 638 f Yersinia enterocolitica , 543 Yersinia pestis , 253 Z Zidovudine, 558 Z-score, 566 Zygoma fractures, 1105 , 1126 –1127 cerebrospinal fluid (CSF) leak, 1127 Le Fort classification, 1127 f unilateral zygomatic arch fractures, 1127