Inferior accessory fissure of the lung

Andrew Murphy and Dr Henry Knipe et al.

The inferior accessory fissure of the lung, also known as Twining's line, divides the medial basal bronchopulmonary segment from the rest of the lower lobe.

This accessory fissure is present in around 12% of people when examined with CT and is visible on 5-8% of frontal chest x-rays. It is approximately five times more common on the right than the left. Commonly it is incomplete and may only extend for 0.5-2 cm 1,3.

Chest
Anatomy: Thoracic
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Article information

rID: 22331
System: Chest
Section: Anatomy
Synonyms or Alternate Spellings:
  • Twining's line
  • Twining's lines
  • Inferior accessory fissure

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Cases and figures

  • Case 1: inferior accessory fissure
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  • Case 2: inferior accessory fissure
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  • Case 3: right inferior accessory fissure
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  • Case 4: right inferior accessory fissure
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  • Case 5: Twining's line
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