Generally speaking, abbreviations such as sched. or SKDs. (SKDs capitalized is mostly within military/governmental usage) will not appear in prose or similarly written texts. They are reserved for titles, headlines, shorthand notes, or other areas where space is a concern.
The pectoral girdle is an imcomplete ring because it is open in the back between what? The KGB Agent answer: The pectoral girdle is an incomplete ring because it is open in the back between the scapulae.
The appendicular skeleton contains the bones of the pectoral girdle, upper limbs, pelvic girdle, and lower limbs. The pectoral girdle (shoulder girdle) contains four bones: two clavicles and two scapulae (Fig. 6.11). It supports the arms and serves as a place of attachment for muscles that move the arms.