The Stirrup (or the Stapes) is a stirrup shaped bone, & the smallest bone in our body, measuring 3.3 millimeters (0.13 inches) in length. It is found in the middle ear, and its function is to transmit sound vibrations from the Incus bone to the inner ear’s membrane-covered opening.
1 4 1
.. Stapes or stirrup,found the middle ear,is the smallest smallest bone in our body

This Is a Certified Answer

As part as I know, stape is the real yet smallest part/ bone of our body. It is called "stape" due to the structural body of it which is identically like "stirrup". It can be located in the middle part cross section of a human ear. As what our scientist says, it is one of the three auditory ossicles of the middle ear (one of the 3 smallest bones in the ears) the two others are the malleus and incus. It measures only by 3×2.5 mm. To see a clear vision of the 'stape', Please see the attachment.

Hope it Helps =)

~Happy Summer Vacation~