Why is the diagonal conjugate important?

The diagonal conjugate, which usually measures 12.5 cm or greater, indicates the anteroposterior diameter of the pelvic inlet. The diagonal conjugate is the most useful measurement for estimating pelvic size because a misfit with the fetal head occurs if it is too small.

What are the three pelvic diameters?

[1] The dimensions of its anteroposterior, oblique, and transverse diameters vary according to the morphological type of the pelvis.

How is the true conjugate determined?

In obstetrics, the distance between the midline superior point of the sacrum and the upper margin of the symphysis pubis. It is the anteroposterior diameter of the pelvic inlet, estimated by subtracting 1.5 to 2 cm from the measurement of the diagonal conjugate.

What is external conjugate?

ex·ter·nal con·ju·gate. [TA] the distance in a straight line between the depression under the last spinous process of the lumbar vertebrae and the upper edge of the pubic symphysis.

What is obstetric conjugate?

The distance between the sacral promontory and a point slightly below the upper inner margin of the symphysis pubis; the shortest diameter to which the fetal head must accommodate to descend successfully through the pelvic inlet.

Which is the highest diameter of female pelvis?

Gynaecoid pelvis(50%): It is the normal female type. Inlet is slightly transverse oval. Sacrum is wide with average concavity and inclination….

• between the farthest two points on the iliopectineal lines.
• It lies 4 cm anterior to the promontory and 7 cm behind the symphysis.
• It is the largest diameter in the pelvis.

Where is the pelvic brim located?

Anatomical terms of bone The pelvic brim is the edge of the pelvic inlet. It is an approximately Mickey Mouse head-shaped line passing through the prominence of the sacrum, the arcuate and pectineal lines, and the upper margin of the pubic symphysis.

How do you find the internal conjugate?

In order to find the true conjugate one has to subtract 1.5—2 cm from the diagonal conjugate depending on the circumference of the radiocarpal articulation: if the circumference makes 15 cm — 1.5 cm, if it makes 16 cm and more — 2 cm.

How do you find the obstetric conjugate?

Antero -posterior diameters:

1. Anatomical antero-posterior diameter (true conjugate) = 11cm. from the tip of the sacral promontory to the upper border of the symphysis pubis.
2. Obstetric conjugate = 10.5 cm.
3. Diagonal conjugate = 12.5 cm.
4. External conjugate = 20 cm.

Which is the highest diameter of pelvis?

Anthropoid pelvis (25%): It is ape-like type. All anteroposterior diameters are long. All transverse diameters are short….

• between the farthest two points on the iliopectineal lines.
• It lies 4 cm anterior to the promontory and 7 cm behind the symphysis.
• It is the largest diameter in the pelvis.

Where does the diagonal conjugate start and end?

It extends from the sacral promontory to the thickest part of the pubic bone and measures 10 cm or more. The diagonal conjugate is the most easily and commonly assessed because it extends from the lower border of the symphysis pubis to the sacral promontory.

Which is the shortest conjugate obstetric or diagonal?

The obstetric conjugate is the shortest of the three. It extends from the sacral promontory to the thickest part of the pubic bone and measures 10 cm or more. The diagonal conjugate is the most easily and commonly assessed because it extends from the lower border of the symphysis pubis to the sacral promontory. It normally measures 11.5 cm or more.

Can a fetus be born with a diagonal conjugate?

If the diagonal conjugate is greater than 11.5 cm, it is justifiable to assume that the pelvic inlet is of adequate size for vaginal delivery of a normal-sized fetus.

How is the diagonal conjugate of the sacral promontory measured?

diagonal conjugate [dī·ag′ənəl] a radiographic measurement of the distance from the inferior border of the symphysis pubis to the sacral promontory. The measurement, which averages around 12.5 to 13.0 cm in adult women, may also be determined by vaginal examination.