Histomorphometric Analysis of Collagen and Elastic Fibres in the Cranial and Caudal Fold of the Porcine Glottis

Summary The porcine glottis differs from the human glottis in its cranial and caudal vocal folds ( C ra F , C au F ). The fibre apparatus of these folds was studied histomorphometrically in adult minipigs. For object definition and quantification, the colour‐selection tools of the A dobe‐ P hotoshop program were used. Another key feature was the subdivision of the cross‐sections of the folds into proportional subunits. This allowed a statistical analysis irrespective of differences in thickness of the folds. Both folds had a distinct, dense subepithelial layer equivalent to the basement membrane zone in humans. The subsequent, loose layer was interpreted – in principle – as being equivalent to R einke's space of the human vocal fold. The next two layers were not clearly separated. Due to this, the concept of a true vocal ligament did not appear applicable to neither C au F nor C ra F . Instead, the body‐cover model was emphasized by our findings. The missing vocalis muscle in the C ra F is substituted by large collagen fibre bundles in a proportional depth corresponding to the position of the muscle of the C au F . The distribution of elastic fibres made the C ra F rather than the C au F more similar to the human vocal fold. We suggest that these data are useful for those wishing to use the porcine glottis as a model for studying oscillatory properties during phonation.