Sacrospinous ligament

The sacrospinous ligament is one of the primary ligaments in the pelvis, providing stability and serving as a point of attachment for several muscles.^[3] Its name gives insight into its anatomical attachments: the sacrum and the ischial spine.

Location

The sacrospinous ligament is situated in the posterior part of the pelvis.^[1] It runs from the sacrum and coccyx to the ischial spine, a bony projection from the ischium of the pelvic bone.

Structure

Shape & Size: The ligament is triangular and thin, with its wider base attached to the sacrum and coccyx, tapering as it attaches to the ischial spine. Constitution: It's composed of tough, dense fibrous connective tissue, making it a strong stabilizing structure in the pelvis.^[5] Attachments:

• Proximal: Its base is anchored to the lateral margins of the sacrum and coccyx.
• Distal: Its apex attaches to the ischial spine of the hip bone.

Relation: It is closely related to the sacrotuberous ligament, with which it forms the lesser sciatic foramen.

Function

Pelvic Stability: The sacrospinous ligament assists in stabilizing the pelvis, particularly preventing excessive tilting of the sacrum.^[2] Formation of Foramen: In conjunction with the sacrotuberous ligament, it helps to form the lesser sciatic foramen, a passageway for several neurovascular structures and tendons. Muscle Attachment: It provides attachment points for muscles like the coccygeus muscle, which plays a role in pelvic floor support.^[8]

Clinical significance

The sacrospinous ligament plays a crucial role in maintaining pelvic stability and integrity.^[4] Clinically, its significance arises in conditions like pelvic organ prolapse, where weakened pelvic floor muscles allow organs like the uterus, bladder, or rectum to descend into the vaginal canal.^[7] Surgical interventions, such as sacrospinous ligament fixation, anchor these prolapsed organs to the ligament, providing structural support. Another noteworthy aspect is the close proximity of the ligament to the pudendal nerve and vessels that traverse the lesser sciatic foramen. Accidental puncture or excessive stretching of the ligament during surgical procedures can jeopardize these structures, leading to complications like pudendal neuralgia.^[6] Moreover, the ligament can calcify or thicken over time, potentially compressing neighboring structures and contributing to pain syndromes. A thorough understanding of its anatomy and potential pathologies can aid in accurate diagnosis and effective management of related clinical conditions.