anomalous insertion of the medial meniscus

Anomalous insertion of the medial meniscus (AIMM) is an anatomical variation of the insertion of the anterior root of the medial meniscus.

Terminology

Defined as a congenital variation in the insertion of the anterior root of the medial meniscus onto the anterior cruciate ligament (ACL). The anterior root most commonly inserts onto the intercondylar notch of the tibia anterior to the ACL . Other meniscal variations include a discoid meniscus and transverse (meniscomeniscal) ligaments.

Differential diagnosis

• displaced meniscal tear
• mucoid degeneration of the ACL
• infrapatellar plica

​​Practical points

• knowledge of the congenital variations of meniscal insertions and other variants will prevent misinterpretation
• the ACL can have three bundles and has been seen in combination with an anomalous insertion of medial meniscus
• bone marrow contusion patterns will aid interpretation in suspected ACL injuries, and the presence of a pivot shift pattern is associated with ACL tears
• if available comparison with old or contralateral imaging will further aid in the interpretation

Siehe auch:

• Innenmeniskus