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Inferior tibiofibular joint

The inferior tibiofibular joint, also known as the distal tibiofibular syndesmosis, is a fibrous joint between the distal ends of the tibia and fibula. It plays a crucial role in maintaining the integrity and stability of the ankle mortise while allowing minimal movement necessary for normal ankle biomechanics.

This joint is of major importance in orthopedic anatomy, sports medicine, trauma assessment, and ankle imaging.

Synonyms

  • Distal tibiofibular syndesmosis

  • Inferior tibiofibular syndesmotic joint

Location

  • Situated at the distal ends of the tibia and fibula

  • Immediately proximal to the ankle joint

  • Forms the lateral boundary of the ankle mortise

  • Between the fibular notch of the tibia and the medial surface of the distal fibula

  • Superior to the talocrural (ankle) joint

Anatomical components

  • Articulating surfaces:

    • Fibular notch of the tibia

    • Medial surface of the distal fibula

  • Interosseous ligament:

    • Thickened distal extension of the interosseous membrane

  • Anterior inferior tibiofibular ligament (AITFL)

  • Posterior inferior tibiofibular ligament (PITFL)

  • Inferior transverse ligament

  • Synovial-lined recess (may be present in some individuals)

Relations

Anteriorly:

  • Anterior inferior tibiofibular ligament

  • Extensor tendons of the ankle

Posteriorly:

  • Posterior inferior tibiofibular ligament

  • Flexor hallucis longus tendon

Medially:

  • Distal tibia

  • Ankle joint cavity

Laterally:

  • Distal fibula

  • Peroneal tendons (inferolaterally)

Inferiorly:

  • Talus and ankle joint

Superiorly:

  • Interosseous membrane of the leg

X-ray appearance

Ankle radiographs (AP, mortise, and lateral views):

  • Tibiofibular clear space: Uniform and narrow

  • Tibiofibular overlap: Maintained on AP and mortise views

  • Alignment: Fibula aligned properly within the tibial incisura

  • Cortical margins: Smooth and intact

CT appearance

Non-contrast CT:

  • Articular surfaces: Well-defined tibial and fibular cortices

  • Joint space: Narrow fibrous interval

  • Fibular notch: Clearly visualized contour

  • Spatial assessment: Accurate evaluation of syndesmotic alignment and congruency

  • Ligaments: Not directly visualized but inferred by joint integrity

MRI appearance

T1-weighted images:

  • Bone marrow: High signal in distal tibia and fibula

  • Cortical bone: Low signal

  • Syndesmotic interval: Low-signal fibrous tissue

  • Ligaments: Low-signal linear structures

T2-weighted images:

  • Ligaments: Low signal intensity

  • Joint recesses: May show minimal fluid

  • Adjacent soft tissues: Intermediate to high signal

STIR:

  • Bone marrow: Fat-suppressed signal

  • Ligaments: Remain low signal

  • Joint margins: Clearly delineated against suppressed marrow

Proton density fat-saturated (PD FS):

  • Ligaments: Sharply defined low-signal bands

  • Joint space: Minimal high-signal fluid if present

CT VRT 3D image

Inferior tibiofibular joint 3d

MRI image

Inferior tibiofibular joint mri anatomy labelled image-img-00000-00000

CT image

Inferior tibiofibular joint ct axial