mediostapedial

from The Century Dictionary.

• noun The median portion of the columella in birds and reptiles. In birds, its inner end is fused with the stapedial plate that fits into the fenestra ovalis.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Anat.) Pertaining to that part of the columella of the ear which, in some animals, connects the stapes with the other parts of the columella.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective anatomy Relating to that part of the columella of the ear which, in some animals, connects the stapes with the other parts of the columella.