Bone in the Upper Chest, Known as the Collarbone
Puzzle 3 of Wonderful Sights Pack
Question is: Bone in the Upper Chest, Known as the Collarbone
and the answer is: CLAVICLE
Word Meaning:
CLAVICLE — (anatomy) The collarbone; the prominent bone at the top of the chest between the shoulder and the neck connecting the shoulder and the breastbone.
Definitions from Wiktionary.