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Posterior cruciate ligament

The posterior cruciate ligament (PCL) is one of the two cruciate ligaments of the knee joint, the other being the anterior cruciate ligament (ACL). It is a strong, broad, intra-articular but extrasynovial ligament that prevents posterior displacement of the tibia relative to the femur and contributes to rotational stability of the knee. The PCL is stronger and thicker than the ACL, making injuries less common but clinically significant when present.

Synonyms

  • PCL of the knee

  • Posterior cruciform ligament

  • Ligamentum cruciatum posterius

Origin and Insertion

  • Origin: Posterolateral aspect of the medial femoral condyle, within the intercondylar notch

  • Course: Runs obliquely downward, backward, and laterally through the knee joint capsule, crossing the ACL to form an "X" pattern of cruciate ligaments

  • Insertion: Posterior aspect of the tibial plateau, approximately 1 cm below the joint line, in a depression between the tibial condyles

Relations

  • Anteriorly: Anterior cruciate ligament (ACL) and synovial folds

  • Posteriorly: Posterior capsule of the knee and posterior meniscofemoral ligament

  • Medially: Medial femoral condyle and posterior horn of medial meniscus

  • Laterally: Lateral femoral condyle and posterior horn of lateral meniscus

  • Superiorly: Femoral intercondylar notch

  • Inferiorly: Posterior tibial plateau and posterior capsule

Nerve Supply

  • Tibial nerve (via branches to posterior capsule and cruciate ligaments)

Arterial Supply

  • Middle genicular artery (primary supply)

  • Contributions from superior and inferior genicular arteries

Venous Drainage

  • Genicular venous plexus → popliteal vein

Function

  • Prevents posterior translation of the tibia relative to the femur

  • Secondary stabilizer against external rotation of the tibia

  • Assists in controlling knee hyperflexion and varus/valgus stability

  • Works synergistically with ACL and collateral ligaments to maintain joint integrity

MRI Appearance

T1-weighted images:

  • PCL appears as a low-signal (dark) band

  • Surrounded by fat with bright signal, improving contrast

T2-weighted images:

  • Normal PCL remains uniformly low signal

  • Partial tear: focal bright signal within otherwise dark ligament

  • Complete tear: discontinuity with high signal fluid replacing fibers

STIR (Short Tau Inversion Recovery):

  • Normal ligament appears dark

  • Pathological changes (strain, sprain, tear) appear bright hyperintense

Proton Density Fat-Saturated (PD FS):

  • Normal ligament: uniformly low signal

  • Partial tears: hyperintense areas within ligament substance

  • Surrounding edema also appears bright

T1 Fat-Sat Post-Contrast:

  • Normal ligament shows minimal or no enhancement

  • Inflamed or injured PCL shows enhancement at tear margins or adjacent capsule

CT Appearance

Non-Contrast CT:

  • Ligament itself is not directly visualized; inferred by position between femur and tibia

  • Indirect signs of PCL injury include posterior tibial subluxation or avulsion fractures of tibial/posterolateral condyle

Post-Contrast CT:

  • PCL fibers are not distinctly enhanced

  • CT arthrography may show contrast leakage into ligament disruption sites

  • Adjacent bone marrow changes and hematomas may enhance, indicating associated trauma

MRI images

Posterior cruciate ligament (PCL) coronal cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

MRI images

Posterior cruciate ligament (PCL) sagittal cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

MRI images

Posterior cruciate ligament anatomy image MRI 3T

MRI images

Posterior cruciate ligament anatomy image

CT image

Posterior cruciate ligament (PCL) axial ct image

CT image

Posterior cruciate ligament (PCL) ct sagittal image