Light and scanning electron microscopy of the porcine mesometrial and paraovarian lymphatic networks.

Uterine lymphatics were examined in 38 pigs using light microscopy, stereomicroscopy, and scanning electron microscopy. Uterine lymphatics were initially filled with plastic materials: Microfil for stereomicroscopy, Mercox-corrosion cast for scanning electron microscopy (SEM), and Micropaque for x-ray photographs. Lymph precollectors of the uterine horns formed two superficial layers, ventral and dorsal. At the level of the ovary, precollectors joined to become collector lymph vessels, which entered nearby lymph nodes. Among the lymph vessels emanating from the uterus, there was a characteristics band of lymphatics that bordered on the isthmus of the oviduct. These passed toward the ovary to form the paraovarian lymphatic plexus. Segments of collector lymphatics were longer than precollectors, had thicker walls consisting of endothelial cells, smooth muscle (uniformly forming a continuous band around lymphatics) and fibroblasts. Both precollector and collector lymphatics were covered and surrounded by a fine network of blood microvessels (vasa-vasorum) especially well seen in corrosion casts (SEM).