Which term correctly names the ligament between the sacrum and the ischial tuberosity?

• A. Sacrospinous ligament
• B. Sacrotuberous ligament
• C. Iliolumbar ligament
• D. Inguinal ligament

Answer: (B)

The ligament between the sacrum and the ischial tuberosity is the sacrotuberous ligament. It runs from the sacrum (and coccyx) to the ischial tuberosity, helping stabilize the sacrum and pelvis and forming part of the boundaries of the greater sciatic foramen in combination with the sacrospinous ligament. This helps distinguish it from other pelvic ligaments: the sacrospinous ligament goes from the sacrum to the ischial spine (not the tuberosity) and helps create the greater and lesser sciatic foramina; the iliolumbar ligament attaches from the iliac crest to lumbar vertebrae; and the inguinal ligament runs from the anterior superior iliac spine to the pubic tubercle.