Since Elmund is Minmatar, all his tattoos have meanings attached. It is unknown how the other clans handle tattoos, but in his clan, the back of his right hand carries his name and family mark and his right wrist carries his clan mark. The rest of his right arm is basically his resume. He carries three Circle marks, with additional lines on the flanks denoting his rank and specialization, one mark for his RMS experience, plus lines denoting his division and rank.
However, ever since he had replaced his right arm with a mechanical prosthetics, the marks along his right arm converted into holos, which can be tuned to include more marks once they are earned. These are only displayed when he rolls up his sleeves. Name, family and clan marks are always laser-etched and precision-inked.
The left arm is for highlights of his life and career. There's one for his academic achievement, one for his reckless actions, with accompanying lines describing them involved MTACs and explosives of various descriptions, one for the stuff he did in the RMS with additional lines to better described the nature of those acts and one for being a capsuleer, with additional lines for first his first one hundred frigate solo kills and another for achieving a high rank in the TLF. The TLF mark was long since removed due to his having being demoted after podding a 'friendly' Wolf pilot in response to his own 'friendly fire' against a wingmate during a skirmish op, but the removal was imperfect so there are still remnants left.
He has a voluval mark on his back, though he does not really make a fuss about it. It's nothing remarkable.
There's another mark at his chest, where his heart is, to denote his 'married' status.
The one on his face is purely decorative.