# shining a flashlight through your hand **URL:** \ **Category:** Factual Questions\ **Created:** [October 3, 2002, 7:56pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729 "2002-10-03T19:56:33Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![waldenfont](https://avatars.discourse-cdn.com/v4/letter/w/97f17d/32.png) [@waldenfont](https://boards.straightdope.com/u/waldenfont)\ **Post date:** [October 3, 2002, 7:56pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/1 "2002-10-03T19:56:33Z")
Hi all - If I press a flashlight against my fingers, I see them glowing in a eerie red light. I see dark lines, which are veins - but I see no bones. Please try this in a dark room to see what I mean. Why do my phalangi (sp?) not show up? is the light somehow routed around the bones? Thanks! Oliver ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [October 3, 2002, 10:34pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/2 "2002-10-03T22:34:09Z")
\<\< goes out to kitchen and gets flashlight \>\> Huh. You’re right. That’s weird. No clue why, sorry. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 3, 2002, 10:47pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/3 "2002-10-03T22:47:16Z")
Yes, the light is dispersed as it travels through the flesh, like this: ```auto LIGHT SOURCE || || -------------Skin /\ / \ / \ /\XXXX/\ **Author:** ![clayton\_e](https://avatars.discourse-cdn.com/v4/letter/c/c57346/32.png) [@clayton\_e](https://boards.straightdope.com/u/clayton_e)\ **Post date:** [October 3, 2002, 11:34pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/4 "2002-10-03T23:34:19Z") Wow… Mange… That was pretty cool. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [October 3, 2002, 11:49pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/5 "2002-10-03T23:49:59Z")
\ You wanna see bones? ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [October 4, 2002, 3:33am UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/6 "2002-10-04T03:33:24Z")
Light travels through human flesh. To what depth? When you’re catching some rays, your inner organs are bathed in (diffuse) sunlight. Think about it. ---
**Author:** ![Virtuosity](https://avatars.discourse-cdn.com/v4/letter/v/35a633/32.png) [@Virtuosity](https://boards.straightdope.com/u/Virtuosity)\ **Post date:** [October 4, 2002, 4:47am UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/7 "2002-10-04T04:47:35Z")
your bones are surrounded by tendons, ligaments, a thin protective covering, and muscle. That is a lot for the light to get through ---
**Author:** ![Tristan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tristan/32/18058_2.png) [@Tristan](https://boards.straightdope.com/u/Tristan)\ **Post date:** [October 4, 2002, 10:23am UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/8 "2002-10-04T10:23:44Z")
If wonder if it would be possible to do diagnostic work like that… hehehehehe I also wonder if a powerful enough light could do my abdomen… well, not **my** abdomen, but someone thin… You get what I’m saying… ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [October 4, 2002, 10:42am UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/9 "2002-10-04T10:42:08Z")
**Possible TMI waning…** On a related note, a few years ago I noticed a lump in… ahem, a rather delicate area. After procrastinating for a few days I went to see the doc (better embarrassed than dead, right?) and explained my fears. Anyway, he prodded about for a bit, and said it was most likely to be a small cyst rather than a tumour, and there was an easy way of finding out. He pulled out a torch (as we ignorant Brits call flashlights) and shone it through the offending part. Hey presto, it shone right through the lump. He explained that this was because the cyst was full of fluid, rather than being solid like a tumour. He also said it would disappear on its own, which it did. He still sent me for an ultrasound scan just to make sure. Now that was interesting - you know how pregnant women get to see their unborn baby on the TV screen? Well I had a similar experience, allowing me to get a whole new perspective on my anatomy… 😉 ---
**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\ **Post date:** [October 4, 2002, 11:50am UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/10 "2002-10-04T11:50:45Z")
You would have thought that I’m beyond the age of putting things in my mouth, but that’s what I did with a small light bulb (low voltage & well insulated of course). Go to a dark room, wait for your eyes to adjust, and light your skull from the inside. See your whole face and your nostrils glow. Creeeepy. I think I’ve heard of a kind of mammography or something like that using red or near infrared light. Computer rendered images of human skin, porcelain or such always look kinda dull, because they don’t consider the internal light dispersion, until you add new special algorithms just to imitate that. ---
**Author:** ![easy\_e](https://avatars.discourse-cdn.com/v4/letter/e/eb8c5e/32.png) [@easy\_e](https://boards.straightdope.com/u/easy_e)\ **Post date:** [October 4, 2002, 7:52pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/11 "2002-10-04T19:52:03Z")
**femtosecond** : a professor in my department is working on just [that](http://www.engr.wisc.edu/bme/faculty/ramanujam_nimmi.html#summary). ---
**Author:** ![HeyHomie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heyhomie/32/207_2.png) [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Post date:** [October 4, 2002, 10:36pm UTC](https://boards.straightdope.com/t/shining-a-flashlight-through-your-hand/130729/12 "2002-10-04T22:36:25Z")
> [@](#): > > \*Originally posted by r\_k \* > \*\*\*\*Possible TMI waning…\*\*Anyway, he prodded about for a bit, and said it was most likely to be a small cyst rather than a tumour, and there was an easy way of finding out. He pulled out a torch (as we ignorant Brits call flashlights) and shone it through the offending part. \*\* Good thing you clarified. For a minute I was thinking that your doctor was going to hold a blowtorch to your nads :eek: ! [sub]Just kidding![/sub]