Ligaments Of The PelvisEdit
Ligaments of the pelvis form a compact, resilient framework that stabilizes the pelvic ring, supports pelvic organs, and helps transfer load from the spine to the lower limbs. Working in concert with muscles and fascial layers, these ligaments restrict unwanted motion at the sacroiliac joints and at the interfaces where the pelvic bones meet. The arrangement also shapes the greater and lesser sciatic foramina, influencing the pathways of nerves and vessels that pass through the pelvis.
The ligaments of the pelvis can be considered in terms of location and function: sacroiliac ligaments anchoring the sacrum to the ilium; ligaments of the lumbosacral junction; ligaments forming the boundaries of the greater and lesser sciatic foramina; and the pubic ligaments that stabilize the anterior portion of the pelvis. Together, they create a stable base for the upper body and a conduit for pelvic contents, while allowing necessary flexibility for movement and childbirth in humans. See also pelvis and sacroiliac joint for broader anatomical context.
Anatomy and key ligaments
Anterior sacroiliac ligament
The anterior sacroiliac ligament extends from the anterior aspect of the sacrum to the wing of the ilium near the sacral auricular surface. It contributes to the stability of the sacroiliac joint by reinforcing the joint capsule on its anterior aspect and blending with the surrounding pelvic fascia.
Interosseous sacroiliac ligament
The interosseous sacroiliac ligament lies between the sacral and iliac bones, within the strong, fibrous region that binds the two bones together. This is one of the densest and most important stabilizing elements of the sacroiliac complex, resisting translational and rotational stresses transmitted from the spine to the pelvis. See sacroiliac joint and ilium for related structures.
Posterior sacroiliac ligament
Posteriorly, the sacroiliac joint is reinforced by the posterior sacroiliac ligament, which runs from the sacrum to the ilium along the dorsal aspect of the joint. This ligament provides substantial stability against posterior shear and rotational forces.
Short and long posterior sacroiliac ligaments
In addition to the main posterior fascial components, shorter posterior and longer posterior sacroiliac ligaments contribute to the complex stability of the posterior pelvis. They lie near the–but distinct from–the posterior sacroiliac ligament and help limit movement at the joint.
Iliolumbar ligament
The iliolumbar ligament connects the lower lumbar spine to the pelvic brim. Originating from the transverse processes of L4–L5 and inserting into the iliac crest, it anchors the lumbosacral junction and helps resist anterior and rotational forces in that region. See ilium and lumbar spine for related anatomy.
Sacrospinous ligament
The sacrospinous ligament runs from the lateral sacrum to the ischial spine. It, together with the sacrotuberous ligament, converts the greater and lesser sciatic notches into the greater and lesser sciatic foramina, shaping the pelvic outlet. See sacrum, ischial spine, and greater sciatic foramen for context.
Sacrotuberous ligament
The sacrotuberous ligament extends from the sacrum and coccyx to the ischial tuberosity. It completes the conversion of the notches into foramina and contributes to the posterior pelvic stability, helping to limit forward tilting of the sacrum under load. See coccyx and ischial tuberosity for connections.
Pubic ligaments (superior and inferior)
The pubic ligaments stabilize the anterior portion of the pelvis at the pubic symphysis. The superior pubic ligament spans across the superior aspect of the pubic symphysis, while the inferior pubic ligaments reinforce the inferior aspect, contributing to the integrity of the pubic joint. These ligaments work with the fibrocartilaginous disc and the surrounding joint capsule to permit minor movement while resisting excessive separation.
Other notes on pelvic connective tissue
The ligaments described above act in concert with pelvic fascia and the pelvic floor muscles to coordinate stability and mobility. They interact with the ligaments of the lumbar spine and hip joints in maintaining overall posture and locomotion. See pelvic fascia and pelvic floor for related structures.
Functional significance
Load transmission: Pelvic ligaments help transfer axial loads from the spine through the pelvis to the lower limbs, distributing forces during standing, walking, and running. This is especially important at the sacroiliac joints, where stability is essential for efficient bipedal gait. See pelvis and sacroiliac joint.
Joint stability: The ligaments provide major restraint against excessive motion at the sacroiliac joints and at the pubic symphysis. They limit anterior, posterior, and rotational movements to maintain pelvic integrity during dynamic activities. See sacroiliac joint and pubic symphysis.
Shaping pelvic outlets: The sacrospinous and sacrotuberous ligaments, by forming the boundaries of the greater and lesser sciatic foramina, influence the pathways for nerves and vessels that pass through the pelvis. See greater sciatic foramen and lesser sciatic foramen.
synergy with surrounding structures: Pelvic ligaments work with the pelvic floor muscles and fascia to support pelvic organs and to moderate movements that could place strain on pelvic contents. See pelvic floor.
Clinical notes
In adults, ligaments of the pelvis can be stressed or injured by high-energy trauma (such as in major falls or motor vehicle accidents), leading to instability of the pelvic ring or injuries to the sacroiliac joint. Conditions affecting pelvic ligaments may contribute to pain or dysfunction of the sacroiliac joint. Pregnancy and childbirth can influence the laxity and function of pelvic ligaments, though this aspect is highly individualized. See pelvic trauma, sacroiliac joint dysfunction, and pelvic girdle for related topics.