Pronunciation: (pek"tu-ral'is, -rā'lis, -rä'-), [key]
—pl. -ral•esPronunciation: (-ral'ēz, -rā'lēz, -rä'-). [key] Anat.
either of two muscles on each side of the upper and anterior part of the thorax, the action of the larger (pec'toral'is ma'jor) assisting in drawing the shoulder forward and rotating the arm inward, and the action of the smaller (pec'toral'is mi'nor) assisting in drawing the shoulder downward and forward.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.