suc·cus·sion 
(s
ə-k
ŭsh
ən)
n.1. The act or process of shaking violently, especially as a method of diagnosis to detect the presence of fluid and air in a body cavity.
2. The condition of being shaken violently.
[Latin succussiō, succussiōn-, from succussus, past participle of succutere, to toss up : sub-, up from below; see SUB- + quatere, to shake; see kwēt- in the Appendix of Indo-European roots.]
suc·cussa·to′ry (sə-kŭsə-tôr′ē) adj.