Citation, DOI & article data
The ligamentum mucosum, also known as the infrapatellar plica, is an embryological remnant of a synovial septum and one of the types of knee plicae.
It is the most common knee plica, with incidence ranging from 65% 4 to 85.5% 5 of the population.
The classification according to the plica morphology was proposed by Kim 4.
- separate type - completely separated from the ACL (60.5%)
- split type - longitudinally divided (13.5%)
- vertical septum type - attached to the ACL (10.5%)
- fenestra type - with fenestrated vertical septum (1.0%)
It is best seen on T2/PD sagittal images as a curvilinear, low signal structure, originating from the anterior intercondylar notch and traversing the infrapatellar (Hoffa's) fat pad to attach to the inferior pole of the patella. It may connect to the anterior cruciate ligament (ACL). Its thickness ranges from very thin to almost as thick as the anterior cruciate ligament.
- 1. Cothran RL, McGuire PM, Helms CA et-al. MR imaging of infrapatellar plica injury. AJR Am J Roentgenol. 2003;180 (5): 1443-7. doi:10.2214/ajr.180.5.1801443 - Pubmed citation
- 2. García-Valtuille R, Abascal F, Cerezal L, García-Valtuille A, Pereda T, Canga A, Cruz A. Anatomy and MR imaging appearances of synovial plicae of the knee. Radiographics : a review publication of the Radiological Society of North America, Inc. 22 (4): 775-84. doi:10.1148/radiographics.22.4.g02jl03775 - Pubmed
- 3. R. Lee Cothran, Philip M. McGuire, Clyde A. Helms, Nancy M. Major, David E. Attarian. MR Imaging of Infrapatellar Plica Injury. (2012) American Journal of Roentgenology. 180 (5): 1443-7. doi:10.2214/ajr.180.5.1801443 - Pubmed
- 4. F J Kosarek, C A Helms. The MR appearance of the infrapatellar plica. (2013) AJR. American journal of roentgenology. 172 (2): 481-4. doi:10.2214/ajr.172.2.9930807 - Pubmed
- 5. Kim SJ, Min BH, Kim HK. Arthroscopic anatomy of the infrapatellar plica. (1996) Arthroscopy. 12 (5): 561-4. Arthroscopy (abstract) - Pubmed