The muscle marked in red is the lateral deltoid. I do not recommend damaging this muscle, as it seems to factor into just about every single frakking movement that your arm can make. Opening doors, putting on shirts/coats, lifting coffee cups, petting cats, rolling over in bed, pushing down that little lever on the toaster. Anything. _
As you’ve already figured out, I’m dealing with this little issue right now. On my way out of the house yesterday the heel on my boot gave way, sending me bumping down my front steps (under the watchful gaze of the ever-vigilant neighbors across the street, yay). My right arm took most of the burden of stopping my fall. Aside from having to change my shoes into something a bit less broken and being slightly damp from the rain-sodden steps, all seemed well at first. A bit later in the evening it became evident that things weren’t entirely well with that right arm. By the time I was in bed I knew that my little spill was going to give me grief for many days to come. The nature and magnitude of that grief wasn’t fully apparent until this morning when I tried getting dressed. It seems something got pulled/strained in the aforementioned muscle.
There’s probably not much to be done about it aside from just sucking it up and dealing with the pain while it heals (and publicly whining about it here, which really doesn’t do anything to help the pain but is still curiously satisfying). Thankfully I don’t have any heavy lifting planned and my typing is unimpeded by the injury.
Still, it’s annoying. To be completely superficial, almost as annoying as the pain is the fact that those were my only black boots, dammit. Both my arm and my wardrobe have taken a hit and I am not amused.