Welcome to Just Answer and thanks for your questions. 1. Os acetabuli are bits of extra bone around the rim of the acetabulum (the hip socket). 2. Dysplastic bump at the lateral femoral head neck junction suggesting femoral acetabular impingement means there is an atypical (dysplastic) bump at the area where the head of the femur meets its neck that suggests that there is an impingement. That means that the ball of the femur (the head) doesn't have full range of motion within the socket and damage can occur when the extra bit of bone hits the cartilage surrounding the rim of the socket. This causes pain and can lead to arthritis. Sometimes it can be fixed with debridement (scraping the excess bone away). The link below has a nice diagram that shows the relationship of the parts to one another.