olecranon       
noun [ C ]  anatomy specialized uk/əʊˈlek.rə.nɒn/ us/oʊˈlek.rəˌnɑːn/  olecrana /əʊˈlek.rə.nə/ /oʊˈlek.rə.nə/
 鹰嘴,肘突
the end part of the ulna (= a long thin bone in the lower arm) at the elbow
  The olecranon forms the point of the elbow. 肘突是手肘的尖点。