RADIOLOGIC ANATOMY H. Erbagci Æ E. Gumusburun Æ M. Bayram G. Karakurum Æ A. Sirikci The normal menisci: in vivo MRI measurements Received: 23 July 2002 / Accepted: 27 July 2003 / Published online: 22 October 2003 Ó Springer-Verlag 2003 Abstract The aim of this study was to determine dimensions of the normal menisci in 174 healthy subjects by using MRI. The menisci were divided into three zones (anterior horn, mid-body, posterior horn). The height and width of the both menisci were measured. For the medial meniscus; the height and width of the anterior horn were 5.32 mm and 7.78 mm, the height and width of the mid-body were 5.03 mm and 7.37 mm, and the height and width of the posterior horn were 5.53 mm and 11.71 mm, respectively. For the lateral meniscus, the height and width of the anterior horn were 4.33 mm and 8.88 mm, the height and width of the mid-body were 4.94 mm and 8.37 mm, and the height and width of the posterior horn were 5.36 mm and 9.70 mm, respec- tively. Three cases (1.7%) of discoid lateral meniscus were encountered. The results of this study should help to establish standard measurements, and to differentiate between normal and pathologic conditions of the me- nisci of the knee joint. Keywords Meniscus Æ Knee Æ Morphometry Æ Biometry Introduction The menisci (semilunar cartilages) are crescent-shaped fibrocartilages deepening the articular surfaces of the tibia which receive the femoral condyles. The semicir- cular medial meniscus has a wide posterior horn, nar- rows anteriorly and has a more open C-shaped configuration than the more circular lateral meniscus. The lateral meniscus has a tight C-shape and is relatively symmetric in width from anterior to posterior [3, 14, 16]. The proximal or superior meniscal surface is smooth and concave, producing greater contact with the femoral condyles. The inferior meniscal surface is flat and rests on the opposing surface of the tibia. The periphery of the menisci is convex and thick, and attaches to the in- side of the joint capsule [3, 4]. The meniscus protects the joint articular cartilage (by acting as a buffer between femoral and tibial surfaces while loading), provides joint lubrication, and increases joint stability (by providing congruity between femoral and tibial articular surfaces) [4, 14]. No technique has been directly applied to the meniscus cartilage or validated with direct measure- ments. Previous attempts to measure the size of the meniscus have varied from simple ruler measurements to more complex techniques involving sterophotogramme- try, moldings and ultrasound [6, 9]. Stone [15] et al. developed and evaluated a magnetic resonance imaging (MRI) technique to measure the volume of meniscal tissues in 1994. They then excised and measured the menisci by water volume displacement. They show that the MRI technique employed to measure the volume of the menisci corresponded with that of the standard measure of volume, and was just as precise. Reicher et al. [10] began a revolution in knee diagnosis in 1985 with MRI. MRI is an excellent technique for evaluation of the anatomy of the meniscus size [2]. Differential diagnosis of small menisci is important in some pathologic entities, as well as bucket-handle tear [13]. Discoid meniscus is a dysplastic meniscus that has Surg Radiol Anat (2004) 26: 28–32 DOI 10.1007/s00276-003-0182-2 H. Erbagci Æ E. Gumusburun Department of Anatomy, Gaziantep University Medical School, Gaziantep, Turkey M. Bayram Æ A. Sirikci Department of Radiology, Gaziantep University Medical School, Gaziantep, Turkey G. Karakurum Department of Orthopedics, Gaziantep University Medical School, Gaziantep, Turkey H. Erbagci (&) Ali Nadi U ¨ nler Bulvarı No: 45/8, 27070 Gaziantep, Turkey E-mail: erbagcihulya@hotmail.com Tel.: +90-342-3220500 Fax: +90-342-3365505