Funneling of the internal cervical os

Dr Henry Knipe and Assoc Prof Frank Gaillard et al.

Cervical funnelling is a sign of cervical incompetence and represents the dilatation of the internal part of the cervical canal and reduction of the cervical length.

Greater than 50% funnelling before 25 weeks is associated with ~80% risk of preterm delivery.

Radiographic features

Good scanning technique is essential, as excessive pressure with the probe, or presence of a distended bladder may artificially narrow the canal. Preferably, a transvaginal scan is recommended for accurate assessment of cervical length and measurement of funneling.

  • percentage funnelling: funnel length/(functional cervical length + funnel length)
  • shape of funneling: V-shaped or U-shaped. U-shaped funneling have a higher risk of preterm delivery 4
  • depth and width of the funnel: V-shaped funnel has a depth with no width; however, U-shaped funnel has the width as an important parameter

See also

Article information

rID: 6509
Section: Signs
Tag: cases
Synonyms or Alternate Spellings:
  • Cervical funneling
  • Funneling of the cervical os

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Cases and figures

  • Figure 1: funnel for illustration of cervical funneling
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  • Case 1: cervical funneling
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  • Case 2
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