Posterior cruciate ligament

The posterior cruciate ligament (PCL) is one of the two cruciate ligaments that stabilize the knee joint. 

Gross anatomy

The PCL attaches to the posterior intercondylar area and passes anterosuperiorly to insert into the lateral surface of the medial femoral condyle. 

When the knee is in extension, it makes an almost 90º turn as it passes anterosuperiorly. The anterior cruciate ligament passes lateral to it and curves around it.

The PCL is intracapsular but extrasynovial and is approximately 13 mm in length and less than 6 mm in anteroposterior diameter. It contains two fiber bundles named according to their relative attachments ¹:

1. anterolateral
2. posteromedial

Function

During flexion, the anterolateral band becomes tight, whereas the posterolateral bundle tightens during extension ¹ and the PCL as a whole acts to resist anterior translation of the femur on the tibia ².

Radiographic features

MRI

The two bundles cannot be separately identified on MRI and the PCL appears as intensely hypointense. The apex of the PCL is susceptible to magic angle effect (an MR artefact) and high signal can be seen in this area but it is of no pathological significance ². 

Related pathology

• PCL tear
• double PCL sign