The sacral promontory is the anatomical term for the superiormost portion of the sacrum

Sacrum

In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...

. It marks part of the border of the pelvic inlet

Pelvic inlet

The pelvic inlet or superior aperture of the pelvis is a planar surface which is typically used to define the boundary between the pelvic cavity and the abdominal cavity .Its position and orientation relative to the skeleton of the pelvis is anatomically defined by its...

. The rectosigmoid junction is at the level of the sacral promontory.

With the iliopectineal line

Iliopectineal line

The iliopectineal line is the border of the iliopubic eminence. It can be defined as a compound structure of the arcuate line and pectineal line...

, it comprises the linea terminalis

Linea terminalis

The linea terminalis or innominate line consists of the pectineal line, the arcuate line, and the sacral promontory.It is part of the pelvic brim, which is the edge of the pelvic inlet. The pelvic inlet is typically used to divide the abdominopelvic cavity into an abdominal and a pelvic cavity...

.

See also

• Sacrovertebral angle
  Sacrovertebral angle
  The sacrum is curved upon itself and placed very obliquely, its base projecting forward and forming the prominent sacrovertebral angle when articulated with the last lumbar vertebra.It is also known as the "lumbosacral angle"....
  
  

Sacral promontory making an angle of 30 degrees from the horizontal plane shows the anatomical position.
it is useful marker for sling operation.

External links

- "The Female Pelvis: Bones"