The smallest diameter of the true pelvis is :
Ans. is a i.e. Interspinous diameter Friends. we have mugged up pelvis in detail for our undergraduate exams but for PGME exams you need not mug up each and everything about pelvis All you need to know are some of the impoant diameters, which I am listing down below. Diameters of Pelvis : Diameter Inlet Mid Pelvis Outlet Antero- Obstetric 11.5 cms 11.5 -- 13.5 cms posterior conjugate is 10 - 10.5 cm True conjugate is 11 cm Diagonal conjugate is 12 cm Oblique 12 cms Transverse 13 - 13.5 cms Interspinous diameter is 10 cms. Inteuberous diameter is 11 cm Note : The smallest diameter is the interspinous diameter. Pelvic inlet is bounded posteriorly by the promontory and alae of the sacrum, laterally by the linea terminal's and anteriorly by pubic symphysis. Mid pelvis The mid pelvis lies at the level of ischial spines (plane of least pelvic dimensions). It is of paicular impoance following engagement of fetal head in obstructed labour.deg The interspinous diameter is (10 cm)deg the smallest diameter of the pelvis.deg Pelvic outlet : The outlet of the pelvis consists of two triangular areas. The apex of posterior triangle is at the tip of sacrum and lateral boundaries are the sacrosciatic ligaments and ischial tuberosities. The anterior triangle is formed by the area under the pubic arch. Posterior sagittal diameter of outlet : It is an impoant diameter in case of obstructed labour caused by narrowing of the mid pelvis or pelvic out let as the prognosis for vaginal delivery depends on the length of posterior sagittal diameter. Posterior sagittal diameter extends from tip of coccyx to a right angle intersection with a line between the ischial tuberosities.
Interspinous Diameter
Diagonal conjugate
True conjugate
Inteuberous diameter