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