Usually the mitral regurgitation jet is toward lateral wall of the left atrium like in this case (video 5). (balkanvets.com)
It has been considered that the major momentum loss occurs at the source lateral wall, where the «radial» momentum is transferred to the wall via an electrostatic ion acceleration in the plasma sheath. (sciencedaily.com)
M. Catala, M. A. Teillet, E. M. De Robertis, M. L. Le Douarin, A spinal cord fate map in the avian embryo: While regressing, Hensen's node lays down the notochord and floor plate thus joining the spinal cord lateral walls. (scienceintheclassroom.org)