The Common Vein

Accessory Fissure

Superior Accessory Fissure

An accessory fissure

• • is an anatomical variation in the lungs
    • where
      an extra fissure divides the lung tissue into additional lobes or segments
    • beyond the usual lobar divisions.
  • It is a congenital variation that occurs during lung development.
  • The pathogenesis involves the
    • incomplete fusion of the lung during embryonic
      development,
    • resulting in an
      • anatomically – an extra cleft of tissue.
      • functionally
        • do not typically affect lung function but may cause confusion during imaging interpretation, as they can resemble pathological conditions like scarring.