Morphological variations, morphometry and microstructure of adult human mitral valve v1

Background:The mitral valve is a structurally complex component of the heart, and precise knowledge of its anatomy is essential for understanding valvular function, disease mechanisms, and surgical or transcatheter interventions. Although numerous studies have reported mitral valve morphometry, anatomical variations, histology, and embryology, the findings are dispersed across different methodologies and populations. Objective:This review aims to comprehensively synthesise published literature on the morphometric parameters, anatomical variations, histological organisation, and embryological development of the human mitral valve, and to highlight their clinical significance. Methods:A systematic literature search was conducted using PubMed, Google Scholar, Scopus, ScienceDirect, and Embase. Original studies reporting mitral valve anatomy based on cadaveric dissection, autopsy, echocardiography, and computed tomography were included. Data on annular circumference and area, leaflet length, height, diameter, leaflet variations, histological features, and developmental aspects were extracted and synthesised narratively and descriptively. Results:Considerable variability was observed in mitral valve dimensions across populations and measurement techniques, with consistently larger values reported in imaging-based studies compared to cadaveric studies. Anatomical variations were predominantly noted in the posterior mitral leaflet. Histological studies demonstrated a layered leaflet structure, while embryological evidence explained many observed anatomical variants.