1. When shani mangal are in 8th house of a horoscope or Mangal is in 2nd and Shani is in 8th or vice versa (either together or opposite 180degrees apart)
a. This combo shows issues with Internal Reproductive Organs (Kidneys for examples) and also 2nd house which shows eyes, teeth, neck.
b. This combo also shows issues with the body-part that is indicated by the sign they are in. For example Shani Mangal are in Kanya raashi: Stomach issues, when in Mithun raashi: Arms/Shoulders, Sinvha raashi: Heart and Spine, In Meen raashi ankles/feet and so on.
c. This combo also indicates that there are chances of that his/her mother could have a miscarriage or some issues with pregnancy after him/her (if of course taken a chance).
So Shani Mangal together or opposite affects the body-part shown by the House(s) and also the body part indicated by the Sign/Rashi they are in.
Apart from this Mangal being "karak" of Blood, Sports, Bikes, Cars, Siblings :: It could also show issues with these things. Need to drive carefully, take care of siblings (karmic burden!) and also not be nasty with masses/workers -- rather help them as Shani is masses -- workers.
Even Mangal in Kark raashi (neech raasshi) could show hemoglobin issues, lack of red-factor in the blood or some content of the blood could shows some deficiency.
Please never forget that Guru's aspect (drushti) in the horoscope changes the outcome quite a bit and it will reduce the impact quite a bit but cannot negate it completely. Guru's drushti would help you pay-off by good-karma and not by sufferings all the time! A real life Guru would do the same in absence of Guru's drushti in the horoscope!
We will continue the discussion on some examples how Astrology could be used to double-check extreme diagnosis by doctor and suggestion for some serious surgery etc should be checked in the horoscope. Almost always, extreme health situations are reflected in the horoscope. Say Mangal-Ketu close in Moola nakshatra could show hereditary issues with blood from maternal family and so on.
Even using Palmistry: Formation of mounts and signs on mounts -- it is very easy to make some assessment on possibility of deceases. I avoid meeting folks as analysing horoscope from a 1000s of miles of distance and making very acurate analysis gives me some mental kick and challenge! :) But when time-date are in doubt, there is nothing better than the Palm and of course face!! :)