A preliminary observational study on the vascular, nerve, and lymphatic anatomy and histology of the labia minora from cadaveric and surgical samples.

INTRODUCTION AND HYPOTHESIS: To better understand details of the fine anatomy of the labia minora, present images of the vascular anatomy and characterize the nerve and lymphatic distribution of the labia minora.

METHODS: Two fixed and five fresh cadaveric specimens were perfused and dissected, and the vascular network was photographed. Labia minora samples, prepared from cadavers, and tissue resulting from labia reduction surgery underwent hematoxylin and eosin staining and S100 and D2-40 immunohistochemical staining.

RESULTS: Arteries emanated from the base to the edge of the labia minora, where there was a larger feeding artery, and the arteries were anastomosed. The veins formed anastomotic branches in the same direction as the edge of the labia minora. Arteries and veins that accessed the labia minora were successfully perfused at the same time with no obvious association. Sensory nerve endings were abundant, mostly larger with myelinated nerve trunks and Schwann cells in the central area with suggested neurovascular associations and smaller with no obvious aggregation at the edge. The medial area had 23.63 ± 11.82 nerves/view, the lateral area 21.30 ± 11.49 nerves/view (P > 0.05). The thickest nerve bundle was 3.16 ± 1.41 mm from the medial epidermis and 3.13 ± 1.47 mm from the lateral epidermis. Lymphatic vessels showed no obvious regional distribution. Labia minora were 21.77 ± 5.69 mm wide with 252.87 ± 63.01 lymphatic vessels at 3.67 ± 1.61/mm2 density. The shortest inner diameter of dilated lymphatic vessels was 161.09 ± 49.99 μm.

CONCLUSION: A larger feeding artery exists in the labia minora, which should be noticed in the pre-surgery design of labiaplasty. No difference was observed in the nerve distribution between the medial and lateral sides. Lymphedema might not be the cause of labial hypertrophy.