Sacroiliitis is an inflammation of one or both of the sacroiliac joints, which connect the pelvis to the sacrum. The sacrum and the iliac bones are held together by a collection of strong ligaments allowing relatively little motion at the sacroiliac joints. With sacroiliitis, even slight movements can cause discomfort or pain.


  • Pain in the lower back, thighs, groin, or buttocks
  • Pain worsens with standing or walking and improves when lying down
  • Inflammation in one or both legs
  • Limping
  • Decreased lumbar or hip range of motion
  • Pain with prolonged sitting
  • Pain during split leg positions
  • Pain with hiking or climbing stairs

Common causes:

  • Traumatic injury - an accident or fall affecting the spine, lower back, pelvis or buttocks
  • Degenerative arthritis (osteoarthritis) - degeneration of the sacroiliac joints
  • Pregnancy - the pelvis stretches to accommodate childbirth, then can realign asymmetrically following delivery
  • Infection
  • Improper stretching
  • Jarring movements to the hip or pelvis such as while jumping and landing hard on the heel, or kicking
  • Gait deviations
  • Asymmetrical standing or seated position
  • Poor posture
  • Muscle imbalances
  • Improper ergonomics
  • Improper lifting mechanics

Risk Factor:

  • Injury or trauma to the spine, pelvis, or buttocks
  • Gender- more often occurs with women
  • Urinary tract infection - the infection may spread from the urinary tract to the sacroiliac joints
  • Pregnancy - pelvic bones expand in preparation for childbirth and may inflame the area around the sacroiliac joints
  • Work or sport which involve awkward or extreme hip positions (gymnastics, martial arts)