0.52. # Cervical length < 18 mm # Funnel length > 9 mm. # Funnel width > 6 mm. o Diagnosis in non - pregnant state: Diagnosis of cervical incompetence in the non-pregnant female is done by Passage of no. 8 hegars dilator during the premenstrual phase of the menstrual cycle. 1) Passage without resistance and pain of No. 8 Hegarrs dilator. 2) Cervicogram : shows funnel shaped cervix. 3) Intracervical balloon studies: Pass a balloon (e.g. Foley's) into cervical canal and inflate it with a radio - opaque dye and then take x - rays after applying due traction. Pear shaped shadow of balloon due to funneling of cervical canal indicates incompetent os. 4) Traction studies : Pass foley's catheter through internal os of cervix and inflate it with 5 - 10 ml and apply traction. If traction of 600 gm or less is enough to pull out the bulb through the os, then the diagnosis is certain. 5) Bromen papaine test : This dye selectively dilates the cervico - uterine junction. After injecting the dye (locally into the cervix and intramuscularly.">