Purpose or Case Report: Developmental variations of the meniscus are common in pediatric musculoskeletal imaging. These range from normal anatomical variants to anomalies causing pain, instability, and secondary injuries. The purpose of this educational poster is to review developmental variations that result in normal anatomic variants or congenital disease.

Normal prenatal and postnatal mensical development is reviewed along with a discussion of the relevant mechanical stabilizers (e.g., intermeniscal and mensicofemoral ligaments, meniscocapsular ligaments, popliteomeniscal fascicles). Sequential embryologic milestones are outlined to demonstrate the formation of the normal meniscal morphology. The role of collagen and vascular organization is discussed to provide insight into the developmental basis of meniscal shape.

Normal anatomic variants (including discoid meniscus, ring-shaped meniscus, hypermobile meniscus, and meniscal flounce) are illustrated. Congenital anomalies (including duplication, hypoplasia, and abnormal attachment) are reviewed. Associated developmental anomalies are also discussed (e.g., thrombocytopenia absent radius syndrome, Larsen syndrome, Ellis-van Creveld syndrome). Important differential diagnoses (e.g., bucket handle tears) will be considered that can result in substantial differences in patient management.

A diagnostic approach is provided for differentiating the various causes of abnormal meniscal development using radiographic and MR imaging. When available, longitudinal imaging, physical examination, and arthroscopic correlations are provided for diagnostic confirmation. Possible complications, associated abnormalities, imaging considerations, and reporting recommendations are also provided to better support next steps in patient care.
Methods & Materials:
Results:
Conclusions: