Sigmoid　sinus　wall　dehiscence　(SSWD)　is　a　common　pathophysiology　of　patients　with　pulsatile　tinnitus　(PT).　However,　the　pathological　mechanism　of　SSWD　is　unclear.　This　study　aimed　to　investigate　the　relationship　between　the　position　of　the　SSWD　and　blood　flow　pattern　of　the　transverse　sinus　and　sigmoid　sinus　(TS-SS)　junction.　The　impact　of　the　blood　flow　was　hypothesized　to　be　the　pathological　mechanism　of　SSWD.　Twenty　patients　and　two　healthy　volunteers　were　analyzed　retrospectively,　and　transient　computer　fluid　dynamics　was　used　to　verify　this　hypothesis.　A　4D　flow　magnetic　resonance　imaging　experiment　was　performed　to　validate　the　numerical　simulation.　The　position　of　high-velocity　blood　flow　impacting　the　vessel　wall　(17/20)　was　consistent　with　SSWD.　In　healthy　volunteers,　the　temporal　bone　was　thin　where　the　blood　flow　impacted　the　blood　vessel　wall.　The　average　wall　shear　stress　(20/20)　and　pressure　(18/20)　of　the　SSWD　area　(peak)　were　higher　than　those　of　sigmoid　sinus　wall　anomalies　(the　contact　area　between　the　vessel　wall　and　the　temporal　bone　at　the　TS-SS　junction).　The　average　wall　pressure　percentage　differences　of　16/20,　11/20,　and　4/20　patients　were　more　than　5%,　10%,　and　20%,　respectively.　The　average　wall　shear　stress　percentage　differences　of　20/20,　18/20,　and　16/　20　patients　were　more　than　5%,　10%,　and　20%,　respectively.　In　brief,　the　blood　flow　of　the　TS-SS　junction　impacted　the　vessel　wall　and　increased　wall　pressure,　which　might　be　an　important　pathological　mechanism　of　SSWD.　This　study　could　serve　as　a　basis　for　the　diagnosis　and　SSWD　resurfacing　surgery　of　patients　with　PT　induced　by　SSWD.