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Tubercle of iliotibial tract

The tubercle of the iliotibial tract, commonly known as Gerdy’s tubercle, is a bony prominence on the anterolateral aspect of the proximal tibia. It serves as the primary insertion point of the iliotibial tract and is an important surface landmark of the knee.

It is a key reference point in orthopedic anatomy, sports medicine, and knee imaging.

Synonyms

  • Gerdy’s tubercle

  • Anterolateral tibial tubercle

Location

  • Situated on the anterolateral aspect of the proximal tibia

  • Just lateral to the tibial tuberosity

  • Anterior to the lateral tibial condyle

  • Inferior to the lateral tibial plateau

  • At the level of the knee joint line

Anatomical components

  • Osseous prominence of the proximal tibia

  • Insertion site of the iliotibial tract

  • Covered by periosteum and overlying soft tissues

  • Adjacent to the anterolateral capsule and fascia

Relations

Anteriorly:

  • Subcutaneous tissue and skin

Posteriorly:

  • Lateral tibial condyle

Medially:

  • Tibial tuberosity

Laterally:

  • Iliotibial tract

Superiorly:

  • Lateral tibial plateau

Inferiorly:

  • Proximal tibial shaft

X-ray appearance

Plain radiographs (AP and lateral knee views):

  • Gerdy’s tubercle: Small bony prominence on the anterolateral tibia

  • Cortical margins: Well-defined and continuous

  • Relationship: Seen lateral to the tibial tuberosity

CT appearance

Non-contrast CT:

  • Tubercle: Well-defined cortical protuberance from the proximal tibia

  • Cortical bone: Intact and dense

  • Trabecular pattern: Normal cancellous bone internally

  • Soft tissue attachment: IT tract inferred by its location

MRI appearance

T1-weighted images:

  • Tubercle cortex: Low signal intensity

  • Underlying marrow: High signal intensity

  • IT tract insertion: Low-signal band attaching to the tubercle

T2-weighted images:

  • Cortical bone: Low signal

  • Marrow: Intermediate signal

  • IT tract: Low-signal linear structure

  • Surrounding soft tissues: Intermediate signal

STIR:

  • Bone marrow: Uniform fat-suppressed signal

  • IT tract: Low signal against suppressed marrow

  • Peri-tubercular region: Well delineated

Proton density fat-saturated (PD FS):

  • Bone marrow: Fat signal suppressed

  • IT tract insertion: Clearly seen as a low-signal attachment

CT VRT 3D image

Tubercle of iliotibial tract 3d

CT image

Tubercle of iliotibial tract ct anatomy labelled image-img-00000-00000

MRI image

Tubercle of iliotibial tract mri anatomy labelled image-img-00000-00000