**2. Anatomy**

Medial Meniscus is a fibrocartilaginous structure composed of collagen fiber that orientates in radial and circumferential fiber. These fibers provided hoop stress function of the meniscus. The width of the medial meniscus being about 1 cm and bigger at the posterior part compared to the anterior part. The semi-lunar shape is divided into 3 segments: anterior horn, body, and posterior horn. In anatomical landmark, meniscus may divide into 5 anatomical zone; the anterior root (zone 1); the anteromedial zone (zone 2a and 2b); the medial zone (zone 3); the posterior zone (zone 4); and the posterior root (zone 5) [22]. The attachment of the medial meniscus to the tibia at the anterior horn and posterior horn are called "medial meniscus anterior root" and "medial meniscus posterior root" respectively. The root of the meniscus itself is not a fibrocartilaginous structure but more like a ligament which serves as an anchor to the tibia. The medial meniscus posterior root attaches to the posterior intercondylar fossa between the attachments of the posterior root of the lateral meniscus and posterior cruciate ligament. The attachment is about 9.6 mm posterior to the apex of medial tibial eminence and 3.5 mm lateral to medial tibial plateau articular cartilage (**Figure 3**) [23–25].

#### **Figure 3.**

*Anatomy of left knee meniscus A: Intact ACL and meniscus knee. B: Drawing axial anatomy of meniscus. The red dot represented the apex of medial tibial spine. The MMPR attached behind this spot about 9.6 mm. ACL = anterior cruciate ligament, PCL = posterior cruciate ligament, AMM = anterior horn medial meniscus, ALM = anterior horn lateral meniscus, AIL = anterior intermeniscal ligament, MM = medial meniscus, LM = lateral meniscus, MMAR = medial meniscus anterior root, MMPR = medial meniscus posterior root, LMAR = lateral meniscus anterior root, LMPR = lateral meniscus posterior root.*

*Medial Meniscus Root Tear: Current Update Review DOI: http://dx.doi.org/10.5772/intechopen.98763*
