Histomorphology of the equine cervix

The cervix provides an effective, morphological barrier between the uterus and the outside world. The aim of this study was to characterize the epithelial morphology and the vascular structures of the equine cervix along the longitudinal and horizontal axis in more detail by light microscopy. For this purpose, cervical tissue specimens that had been removed from five different regions along the caudocranial axis of 10 genitally healthy mares were available. The histological staining was carried out with haematoxylin-eosin, azan according to Heidenhain, periodic acid-Schiff reaction and resorcinfuchsin. An average epithelial cell height of 17.5 +/- 1.7 mum is measured, there being differences in the various areas of the mucosal folds and along the longitudinal axis of the cervix. Three types of cells can be differentiated morphologically. Contrary to the data in the literature, in a large number of cells the free cell membrane shows a clearly discernible border of kinocilia along the total cervical canal. The deep layers of the lamina propria mucosae show pronounced vascularization (46.3 +/- 25.1 vessels/mm(2)) that mainly consists of veins and venules. Support of the occlusive function of the cervical canal in the form of a cavernous body is assumed to be the function of this vascular plexus.