Memory medical terminology word rootVersion en ligne to know more about root words in skeletal system par mohamed said -petr- Vertebral spine, vertebral column -rachi- Cranium Sacrum Relating to the petrous portion of the temporal bone Relating to the lumbar region of the spine -sacr- -lumb- -crani- Sternum, breastbone -spondyl- / - vertebr- -pelv/i- -cost- -clavic- / -clavicul- Clavicle, collarbone Ribs Pelvis, pelvic bone -stern- Vertebra, spine, vertebral column