Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 25; Flight Crew Total 12700; Flight Crew Type 175
Flight Deck / Cabin / Aircraft Event Illness / Injury; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Returned To Departure Airport; General Physical Injury / Incapacitation
Environment - Non Weather Related; Procedure
We were cleared to fl340 for crossing traffic; on our way direct to LEATO intersection; northwest of FNT VOR.  We were not given any traffic to look for. After a few minutes we were cleared to continue climb to FL380. Not long around FL350 we hit one hard bump/jolt which resulted in passengers hitting their heads on the ceiling and one person also hitting her face on the table leaf that had folded during the encounter.  Right afterwards when checking for traffic I saw to the right of the aircraft out the window what looked like what was left of a contrail but could not see the generating airplane. I believe we had encountered some wake turbulence. After checking with the passengers they asked us to return to our departure airport due to a passenger injury. We asked ATC to return to our departure airport. ATC asked about the nature of injuries. When landing we told the tower that we had things under control and did not need any further assistance. I did not think the encounter was 'severe' as I still had my seatbelts fastened during the encounter and did not hit my head on anything. One of our company mechanics did a severe turbulence inspection anyway of the aircraft and did not find any defects; returning the plane to service.
We were cleared to climb to FL400. We asked for FL380 as our final. We were re-cleared to FL380. 300 feet prior to FL340; Cleveland Center asked us to maintain FL340. After a couple minutes they cleared us to climb to FL380. Shortly after we initiated the climb; we got a strong jolt from the left. We both looked out our windows and saw a contrail and determined that we had just hit wake turbulence. The weather was clear and there was no turbulence prior to the one strong jolt we received. The autopilot did not disengage. We did not have any warnings from our TCAS. ATC did not point out any traffic. We had two passengers on board. One had hit her head so we asked ATC for a turn back to our originating airport. The passenger ended up being fine and we landed at normally.
CE-560  Captain reported 'one hard bump' from a possible wake encounter at FL350 that resulted in a passenger injury.