pessulus

plural pessuli

1. anatomyA delicate bar of cartilage connecting the dorsal and ventral extremities of the first pair of bronchial cartilages in the syrinx of some birds.

   The pessulus narrows greatly and becomes somewhat "keel-shaped" in the tracheobronchial junction

   1995, The Condor

   1 more example

   Sound is produced not by the internal but by the external tympaniform membranes; moreover, the pessulus is separate from the tympanum and is attached by the syringeal ligament to the connective tissue sheath enclosing the sternotrachealis muscles

   1982, Donald E. Kroodsma and Edward H. Miller, Acoustic Communication in Birds: Production, Perception and Design Features of Sounds