interclavicle

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A bone located in front of the sternum and between the clavicles in certain vertebrates, such as reptiles and amphibians.

from The Century Dictionary.

• noun In zoology and anatomy, a median membrane bone developed between the clavicles, or in front of the breast-bone, in many Vertebrata.

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

• noun (Anat.) See episternum.

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

• noun anatomy The episternum.