Find the word definition

Wiktionary
hemarthrosis

n. (context pathology English) bleeding in the joints

Wikipedia
Hemarthrosis

Hemarthrosis (or haemarthrosis, plural h(a)emarthroses) is a bleeding into joint spaces. It is a common feature of Hemophilia. The presence of it excludes the Idiopathic thrombocytopenic purpura (ITP).