How dangerous is Santa Ana Neighborhood in Panama City, Panama?
To the best of my recollection, Santa Ana is adjacent to two, shall we say "edgy" neighborhoods: Calidonia, which is less dangerous, and El Chorrillo, which is more so. For perspective, on a scale of 1 - 10, with 10 being more dangerous, Santa Ana is an 8, while Calidonia and El Chorrillo (a slum) is a 7 and 10 respectively.
If circumstances compel you to be in Santa Ana, if possible, stay closer to the Calidonia border, demarcated by Santa Ana park at one end of la peatonal - Central Avenue's pedestrianized shopping strip. The danger in each of the aforementioned neighborhoods increases as the sun goes down.
It would also behoove you to use common sense as you move about the city. Resist any temptation to go down a dark alley; keep a low profile and try to blend-in as much as possible. Don't "flash" expensive jewelry and cameras, or announce you're a tourist with eccentric behavior, particularly in the more dangerous neighborhoods.
Casco Viejo (the city's colonial quarter) is relatively safe and is guarded by special tourist police. I mention it because it's a very nice area, teeming with tourists. I would be remiss, however, if I didn't also mention that it's adjacent to Santa Ana and (more importantly) El Chorrillo. The closer you are to Santa Ana, the safer you'll be...
Recapping: In terms of danger, on a scale of 1 - 10, Santa Ana is an 8, adjacent to El Chorrillo, a 10.
(I could tell you about the safer areas of Panama City, but I'll wait for you to ask.)
Santa Ana is a poor but vibrant neighborhood and not really dangerous. There are a few housing projects being developed in the area which is very much up and coming.