By enriching the knowledge of these variable anatomical position of the IPBSN, surgeon can try to minimize the risk of nerve damage by avoiding the high risk zones while performing medial knee incision, blind puncture or an arthrotomy thus avoiding the unwanted complications.

SUMMARY:The morphometrical data related to the menisci of the adults have been reported by few authors and that of the fetuses have not been reported. The aims of the present study were to analyse the external circumference thickness, the width, peripheral and inner border lengths, and the distance between anterior and posterior horns of the fetal menisci and to compare the meniscal dimensions with that of the adult meniscal parameters which are available in the literature. The menisci from 106 knee joints of the formalin fixed South Indian fetuses which were obtained from the anatomy department were analysed. The fetuses which had musculoskeletal anomalies were excluded from the study. A vernier caliper of 0.02 mm accuracy and a non elastic cotton thread were used for the morphometry. After comparing the meniscal dimensions of the present study with the adult meniscus parameters, we established that the fetal parameters of the meniscus are entirely different from the adults. These differences are may be due to the mesenchymal differentiation or variability of the vasculature early in embryonic life. We believe that our study will provide support to the fetal anatomy, concerning surgical procedures and arthroscopy of the knee joint. Since the morphometric studies of the fetal menisci are not reported, this study may be considered new and needs to be studied further with different groups of fetuses from various stages of intrauterine development. This study is important not only for orthopedic surgeons, but also for morphologists and embryologists.

In the present study, the objectives were to study the morphology of the lateral menisci (LMs) in human fetuses from a South Indian population and to verify the developmental etiology of the discoid lateral meniscus (DLM). The study included 106 fetal knee joints which were fixed in 10% formalin. After dissecting the joints, the morphological variants of the shapes of the LMs were macroscopically noted and classified as discoid and nondiscoid. The nondiscoids were subdivided into C-shaped and crescentic. The discoid lateral menisci (DLMs) were divided into complete and incomplete discoid. From our observations, 82.1% of the LMs were found to be nondiscoid. Among them, 62.3% were C-shaped and 19.8% were crescentic. The remaining 17.9% of the LMs had a discoid shape, and among these, 14.1% were incomplete discoid and 3.8% were completely discoid. Bilaterality of the discoid shape was observed in 26.6% of the cases. There was a female preponderance (11:8) among LMs with discoid morphology. In conclusion, the prevalence of DLM according to the present study was estimated as 17.9%. Our findings favor Kaplan's theory, as the majority of the fetuses of various gestational ages had nondiscoid LMs. Even the youngest fetus (CRL 88 mm, 14 weeks of gestation) exhibited a lateral tibial plateau that was incompletely covered by the meniscus, which did not exhibit a discoid shape. We believe that the DLM is anomalous and arises through variant morphogenesis.

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