If you want to see your Clavicle, you're gonna need a mirror

In a white porcelain shower
that's still unfamiliar
I run a few fingers across my collarbone,
and it too seems a foreign thing
this primeval harness.
Though while the water hisses and trickles down
me, this ossified Collar of Esses
feels less like the reins of destiny
and more the foreign spike,
a bone-sword who pierced me from behind
three million years before.
Look down for a wound, but of course
I can't see; and this small revelation
is perhaps the only moment
throughout my adult life
when I've discovered anything on my own
that once was called “a natural fact.”
I rub the thin skin that hides it
and know, I'm always only millimeters away
from that which keeps my consciousness
afloat, feeling majestically delicate
as the water all around me
pounds itself into steam.