Ligamentum mucosum

Infrapatellar
plica (ligamentum mucosum). PD-weighted and PD-weighted fat-suppressed sagittal MR images of the infrapatellar plica (red arrows) coursing from the intercondylar notch towards the inferior pole of the patella.
www.eurorad.org • CC by-nc-sa-4.0
Infrapatellar
plica (ligamentum mucosum). PD-weighted and PD-weighted fat-suppressed axial MR images of the infrapatellar plica (red arrows) coursing from the intercondylar notch towards the inferior pole of the patella.
www.eurorad.org • CC by-nc-sa-4.0
Infrapatellar
plica (ligamentum mucosum). Schematic diagram of the synovial plicae of the knee (SP=suprapatellar plica, LP=lateral patellar plica, MP=medial patellar plica) and an axial MR image showing the infrapatellar plica (red arrows).
www.eurorad.org • CC by-nc-sa-4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

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.

Epidemiology

It is the most common knee plica, with incidence ranging from 65%  to 85.5%  of the population.

Classification

The classification according to the plica morphology was proposed by Kim .

  • 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%)

Radiographic features

MRI

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.

Related pathology

  • ligamentum mucosum injury
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Plica infrapatellaris: