Date: 202108
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: B737-900
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi; Cruise
ATC / advisory: Ground ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Distraction
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Illness / Injury; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: Taxi
Result: General None Reported / Taken
Contributing factors: Human Factors; Procedure; Environment - Non Weather Related
Primary problem: Human Factors

Narrative: After pushback from Gate XXX and given our taxi instructions 'XX-XY-XZ etc...' to XXL for departure; we commenced our single-engine taxi. While I was taxiing at a slow speed; taxi light on; I noticed a truck that appeared to be stopping on the roadway across Taxiway X between XZ and XY to give way to our aircraft. However; the truck did not stop and they rolled right through Taxiway X without giving way to our aircraft. I applied brake pressure to prevent the plane from hitting the truck. Due to the slow taxi speed; we did not think the braking action to prevent the collision was too firm to knock anyone down or warrant a drastic brace from anyone if they were up. We notified ATC about this taxiway incursion and they asked if there was an Operations car on frequency to go after the truck. We took off; were in cruise; and were past the CP (Critical Point) - [middle of the flight] - when we set up for the first bathroom break. I went out first and I asked [the] First Class Flight Attendant (FA); 'If everything is all right back here.' They responded; 'Yes.' I went to the bathroom; came back up to the cockpit; and was talking to the Purser who also said everything was 'fine' as well. When the First Officer (FO) came back he then informed me that [the] FA informed him that when I had to brake to not hit the truck; she hit her right side against the forward galley wall with some of the quarter turn edging. I then called back and asked if she needed medical help in ZZZ1. She replied that she was icing it and took Tylenol and she would not need medical attention in ZZZ1." I asked the other FAs if they were all right; one stated that they didn't even feel the braking action and two others stated they felt it as they were standing but everyone else was fine. To be clear; the first time I was told something was wrong was past the CP. Before departure I briefed the FAs that if there is anything wrong or abnormal; even if we are in sterile cockpit; do not hesitate to call up and let us know. Also; during the flight; no calls to see if [there were] medical personnel on board to help with an injury were made by the FA crew.Prior to the top of descent when we set up for another bathroom break; the Purser came in and I asked him how [the] FA was doing. He said; 'She seems fine; she wants to go home; she's just a little sore.' When I went out; I asked how she was doing. She stated; 'She wanted to call in enroute injured; but then wanted to deadhead home.' I told her; 'I don't know that they will be able to deadhead her home; but if she is enroute injured please let me know and I will contact Dispatch.' She then said she was 'enroute injured.' I said; 'Do you want medical treatment in ZZZ1.' She said; 'No.'I then texted Dispatch that we had an FA who was enroute injured and would call them when we landed per the reporting requirements. I also requested priority handling and asked the paramedics to meet the aircraft to evaluate her; just to be safe. We landed without incident. When the paramedics came on board; [the] FA refused additional medical care from them and stated to the FO; 'Why did you call them out; you didn't need to do that.' Appropriate reports were made per the manual to the Dispatcher [and others]."


Second narrative: During our flight from ZZZ to ZZZ1; most of which was uneventful; we had a minor injury on taxi out of our galley Flight Attendant (FA); but we were not notified until after the CP (Critical Point); [middle of the flight]. On taxi out we had to stop taxi for a truck that did not stop as we were taxiing X XY XZ from Gate XXX. As we came to a stop at the XX XY intersection; we at the time were more concerned about the truck that did not stop; and believed that we did not stop too abruptly for the truck but just more startled that it did not stop. Hindsight; we did not hear any clunking or hitting - and although we stopped slightly faster than normal; we did not realize that [the] FA may have been knocked off balance a little bit. We did make a call to Ground to let them know that the truck did not stop but we quickly continued our taxi not thinking too much of the incident. While the initial incident where [the] FA hit her arm may not have been that bad; it sounded like it got worse as we flew with some aching and building pain; so she let the flight crew; us; know about her sore arm and sore neck.As the flight continued; we reached radio/ACARS reception into ZZZ1 when [the] FA decided that the pain was too much and she was in flight injured and would not be able to work the return flight leg from ZZZ1 to ZZZ. As I continued to fly; the Captain (CA) coordinated with Dispatch and attempted to call ZZZ1 Operations to let them know the situation. After the CA was given all the information and was notified that she was incapacitated and unable to work the return flight; the decision was made to request priority handling [and] have paramedics meet us at the gate when we arrived to check on [the] FA.At top of descent the decision was made by [the] FA that her arm was hurt too much and after coordination with [the] FA; Dispatch; and calling Operations; we were approximately over ZZZ2 and the CA decided to request priority handling as a precaution due to an incapacitated crew member and in the best interest of the crew member's health. Our flight landed and taxied uneventfully and [the] FA [was] checked out by the airport paramedics. As we left the flight; we wished FA a speedy recovery; she seemed in good spirits.


Synopsis: B737 flight crew reported that a Flight Attendant sustained a minor injury due a braking event on the runway to avoid a truck not giving way to the taxiing aircraft.