As the arms of the child reach up and out to secure to his mother, the teres major and rhomboids run from humerus to spine to
center the scapula. The levator at the top steers this mobile plate. The serratus anterior muscles are powerful forward pullers of the scapula that attach by passing the full width of the under surface of the
scapula (which is lined by the subscapularis) to reach the vertical medial edge where it afixes.