Intervascular smooth muscle fibers and muscular bolsters in nasal swell bodies of humans.

There is strong clinical evidence that the cavernous tissue (swell bodies) of nasal mucosa plays an important role in congestion of the nose. Still, the complex mechanisms responsible for the unique behavior of these vessels have not yet been identified, and even the morphology of these structures is still a matter of controversy. The present study was performed on nasal mucosal specimens from inferior turbinates of humans by means of histology and transmission electron microscopy. Besides the evaluation of the vascular wall structure of the nasal swell bodies, special attention was given to two morphological peculiarities: intervascular smooth muscle fibers and muscular bolsters. Intervascular smooth muscle fibers are composed of bundles of smooth muscle cells varying in diameter between 14 and 35 microns; they are attached to the muscular coat of the vessels of the cavernous tissue. Muscular bolsters are distinct protrusions of the vascular wall in nasal swell bodies; they are found not only at the transition between different vessels, but also irregularly within the course of veins of the cavernous tissue. The authors report on their understanding of the functional significance of intervascular smooth muscle fibers and muscular bolsters within the cavernous tissue for swelling mechanisms in the nose and discuss their results in light of the literature.