Agate,
Can I be a nag for a minute? I fell and hit my head on a heat duct floor grate. I lay there and no way could I have crawled to a pull-cord. Luckily my lungs worked and DH was home to hear me yell. When I fell off a chair fixing DD's curtain (stupid, yes I know) I yelled for poor little DS and said as I lay bleeding (I knew head wounds always bleed a lot) "If Mommy passes out, call 911".