Definition of sacrum in US English:



  • A triangular bone in the lower back formed from fused vertebrae and situated between the two hipbones of the pelvis.

    • ‘The nurse performs a sterile skin prep extending from the patient's lower back area to his or her sacrum and perineum using povidone iodine scrub and paint.’
    • ‘Go ahead and lay supine and see if you can get your cervical vertebrae and sacrum on the ball simultaneously, with your femur parallel to the floor.’
    • ‘New Attitude - black nylon and spandex ‘underwear’ - has an adjustable pad that presses firmly against the sacrum, a bone in the pelvic area.’
    • ‘The lowest lumbar vertebra articulates with the sacrum, and this in turn with the coccyx.’
    • ‘His major complaint was lumbar pain near the sacrum and tailbone.’
    • ‘The spinal column is composed of seven cervical vertebrae, twelve thoracic vertebrae, five lumbar vertebrae, the bony sacrum, and the coccyx.’
    • ‘In 68% of individuals studied, the division occurs between the fifth lumbar vertebra and the upper border of the sacrum.’
    • ‘The vertebral body becomes larger toward the sacrum where more weight is carried.’
    • ‘An abdominal film showed multiple vertebral anomalies in the sacrum.’
    • ‘Giant cell tumor of bone is a rare neoplasm usually seen in the long bones or sacrum.’
    • ‘At the bottom of the spine is a large, solid bone called the sacrum.’
    • ‘Compression fractures can occur anywhere from the occiput to the sacrum.’
    • ‘He said the dreaded Bermuda triangle, an area from the sacrum down the buttocks cheeks, over the anus, is no longer the danger zone it was thought to be in the 1980s.’
    • ‘In other tetrapods, haemal arches do not begin for several vertebrae posterior to the sacrum.’
    • ‘People who have an aligned sacrum (where the spine meets the pelvis) can keep their legs perpendicular to the floor when they bend, but I couldn't.’
    • ‘A small surgical opening is made over the sacrum and a lead is placed near the sacral nerve that influences bladder control.’
    • ‘The sacrum, coccyx, and the two coxal bones form the pelvis.’
    • ‘X rays may show inflammation where the sacrum meets the pelvis.’
    • ‘These sit in between your hip bones and the sacrum bone in your lower back.’
    • ‘Vesalius said that the human sacrum normally has five vertebrae but one of six is by no means rare.’


Mid 18th century: from Latin os sacrum, translation of Greek hieron osteon ‘sacred bone’ (from the belief that the soul resides in it).