From the Research
Below the lumbar vertebrae are the sacral and coccygeal vertebrae, with the sacrum consisting of five fused vertebrae (S1-S5) and the coccyx typically consisting of 3-5 fused vertebral segments 1. The sacrum connects to the pelvis at the sacroiliac joints and serves as an anchor point for many muscles and ligaments.
- The sacrum and coccyx provide stability for the pelvis and serve as attachment points for muscles involved in bowel and bladder function.
- The sacrum contains openings (sacral foramina) through which nerves pass to supply the lower extremities and pelvic organs.
- These vertebrae are crucial for weight transfer between the spine and the lower limbs during standing and walking. The most recent study on the topic, published in 2024, found that the sacrum and coccyx undergo shape changes during pregnancy and after delivery, with pregnant women having a significantly straighter coccyx and combined sacrum-coccyx than nulliparous and parous women 1.
- The study used both 2D and 3D measures to quantify the remodeling of the sacrum and coccyx.
- The results showed that the sacrum and coccyx returned to a more curved configuration after delivery, but not completely. Overall, the sacral and coccygeal vertebrae play a crucial role in the stability and function of the pelvis and lower limbs, and their shape and structure can change during different life events, such as pregnancy and delivery 1.