The anterior and posterior macula flava are located at the anterior and posterior ends of the vocal folds. The macula flava have a peculiar structure with dense elastic fibers, but their functions are unknown.
The physiologic properties of the macula flava are thought to be determined by the alignment and distribution of collagen and elastic fibers.
We studied the three dimensional arrangement of collagen and elastic fibers in the macula flave of the human vocal fold by scanning electron microscopy after dissolving the cellular elements and the collagen fibers with a 90% formic acid treatment and, also, digesting the cellular elements and the elastic fibers with a 10% sodium hydroxide treatment.
This study revealed that the anterior macula flava consists of lumps of fine collagen fibers and fine elastic fibers, detached from the thyroid cartilage, whereas the posterior macula flava consists of thick bundles of collagen and elastic fibers running longitudinally and connecting directly to the arytenoid cartilage.
It was speculated that the anterior macula flava have a massive mixed structure composed of collagen fibers and elastic fibers which run separately in the vocal ligamentum, to form the fulcrum apart from the thyroid cartilage.
Furthermore, the posterior macula flava have a structure corresponding to the longitudinal strong force.
