Meniscal Tear
Hema N. Choudur, Anthony G. Ryan, and Peter L. Munk
Clinical Presentation
Five different patients presented with joint line pain. A history of trauma to the knee accompanied by an audible “pop” was given by the three younger patients. Limitation in knee flexion with no history of trauma was given by the two older patients.

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3F

Figure 3G

Figure 3H

Figure 3I

Figure 3J
Radiologic Findings
A T1-weighted sagittal image (Fig. 3A) shows a complex tear in the posterior horn of the medial meniscus. A T2-weighted sagittal image shows a complex tear in the posterior horn of the lateral meniscus (Fig. 3B).
Figures 3C–3G show a flipped fragment of the posterior horn of the medial meniscus with the characteristic double posterior cruciate ligament sign.
Sagittal T2-weighted (Fig. 3H) and sagittal T1-weighted (Fig. 3I) images show a missing segment of the posterior horn of the medial meniscus. A sagittal T1-weighted image (Fig. 3J) shows a linear oblique tear surfacing inferiorly in the posterior horn of the medial meniscus. Another sagittal T1-weighted image (Fig. 3K) shows a linear vertical tear in the posterior horn of the medial meniscus.
Diagnosis
Meniscal tears.
Differential Diagnosis
None.
Discussion
Background
The menisci are semilunar cartilages that serve to increase the congruency between the femoral condylar articular surfaces and the tibial plateau. The menisci serve various functions, including load transmission, stability, joint proprioception, shock absorption, and articular cartilage nutrition.
The medial meniscus is thicker than the lateral, with the anterior horn about one third the thickness of the posterior, covering ~50% of the tibial plateau. The lateral meniscus is of uniform thickness anteroposteriorly and covers ~75% of the tibial plateau. When viewed from above, the meniscus has a crescent shape (meniscus means “little moon” in Greek). The meniscal ring is thickest at the periphery and tapers off centrally, creating a shallow cup to hold the rounded condyles of the femur. In cross section, the meniscus has a triangular wedge shape.

Stay updated, free articles. Join our Telegram channel

Full access? Get Clinical Tree

