Sacral Promontory

Sacral promontory indicates portion of the margin of the pelvic inlet and is the extended part of sacrum. The sacral promontory joins at an angle which is approximately 30 degrees and is called sacrovertebral angle. The apex is pointed downward and has an oval facet for combining together with the coccyx.

Both sacral promontory as well as presacral space is generally enveloped via the sigmoid colon. Here, the sigmoid colon is connected to the peritoneum, which is conveyed over the left psoas major muscle along with iliacus muscle, once the sigmoid colon is withdrawn towards the left side; the sacral promontory can be recognized easily.

Sacral Promontory

Clinical Significance

Surgical Palpation

Access to The presacral space and sacral promontory can be gained through mildly elevating the peritoneum upwards directly over the sacral promontory as well as creating a midline longitudinal incision. This method inside the presacral space will prevent damage towards the right common iliac artery along with left common iliac vein.

Laparoscopic Procedure

Careful dissection is done in order to reduce the risk of nerve injury, when executing a Laparoscopic procedure. The anterior longitudinal ligament is opened by mild blunt dissection of the presacral tissues above the sacral promontory, sharp dissection after entering the presacral space and the usage of ablative techniques in order to approach the anterior longitudinal sacral ligament should be dodged. One should avoid unnecessary use of sutures or fastening devices onto the sacral promontory whenever fortifying the prosthetic material towards the sacral promontory.

Labor – Child delivery

In order to palpate the sacral promontory as a protuberant bone an effort is made.

• From the connection of first as well as second sacral vertebrae, sacral promontory can be distinguished, where there is a protuberance as well, when it is felt that the bone over the sacral promontory draws back; however, not over the junction of first as well as second sacral vertebrae.
• A sign is presented via index finger of the left hand above the index finger of right hand immediately underneath the pubic angle, if sacral promontory is accessible and also the right fingers are carried out from the vagina and the measurement in the middle of the tip of the middle finger as well as the marked point is measured.
• Diagonal conjugate is the measured by this. Obstetric conjugate is calculated based on the height as well as inclination of symphysis pubis by deducting 1.5 cm to 2.0 cm from diagonal conjugate.

Sacral promontory is not reachable in normal pelvis. Palpation of the sacral promontory indicates small anteroposterior diameter.