Yeah, I’m in my 50s and never broken anything, and that’s counting time playing football, wrestling, karate, and 30-some years riding motorcycles with a couple of spills. Writing it down, I’m getting now why people are always surprised. 
Vampires seem to walk the line between corporeal and ethereal. They don’t show up in mirrors, which is more ghost-like - or at least evidence that there’s nothing physical there - and they can become mist, bats, etc.
They’re strong, but not muscular. Their strength comes from something besides musculature.
So I think arguing about the sternum is anthropomorphizing too much. They’re just…whatever they are. Bullets through the heart won’t kill them, but a wooden stake pierces them easily. It is what it is.
In the older vampire movies, you didn’t just bring a stake, you brought a stake a mallet to hammer that thing home. Problem is, it’s hard to work that into a Kung fu fight sequence.
Of course, in the older vampire stories, a stake through the heart didn’t kill the vampire at all. It just nailed him to the ground so he couldn’t get up and make mischief.
Depends on the culture, I think.
Regards,
Shodan
There have been a few old "vampire graves"found in recent years. But they’re all speculated to be vampire graves by archaeologists interviewed by the press at the time of discovery. I haven’t heard of any kind of scientific consensus being reached.
The most recent grave was in Poland, and the heads were removed and placed on their legs. (Does not match Cecil’s report, but then why would vampire lore be consistent?) Could have been a sign that folks feared they’d become vampires. Could have been a sign of disrespect. With no records, it’s hard to correctly infer intent.
Don’t tap on the glass!
It frightens the Dopers.
I like the more scientific approach that Blade the Vampire Hunter and especially the Shadowrun game took towards vampirism.
In Shadowrun, vampires had allergies to wood and garlic, which is what made them so vulnerable to a garland made of garlic cloves or a wooden stake through the heart. Additionally, there was a reasonable rule applied to near-future technology with regard to vampires: sawing one in half with a machine gun - even though it involved neither wood nor garlic - was going to be pretty hard for one to recover from!
I like the scene from Roman Polanski’s Fearless Vampire Hunters. The old pro hunter gives a stake and a mallet to his apprentice and gives very detailed instructions on how to stake a vampire. IIRC he says to place the stake to the left of the sternum and drive it between the ribs.
I recall how in the Parasol Protectorate series, vampires are allergic to garlic and werewolves to basil, which is the explanation for Italian cooking. It’s an anti-supernatural provision.
In Saberhagen’s Dracula series garlic bothers vampires because they have a superhuman sense of smell. They are also vulnerable to organic substances of all types; wood just happens to be the most convenient most of the time, but something made from bone, antler or horn will work just fine. Wooden bullets work well. Metal on the other hand just passes through with no more than a momentary pain.
I’d never broken a bone before hitting age 40. In the last 8 years, I’ve broken two toes, and my tailbone. 
from what i can tell calcium is not a large part of a vampire’s diet. also they don’t seem to have vita. d as a priority.
there are trade offs in being immortal, perhaps bone strength is one of those things you give up for fast healing and a lovely polished pallor.
i have cracked bones, but haven’t broken one into separate pieces. i unlike vampires, eat quite a bit of chocolate to keep my calcium levels up and bones strong.