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Fibula shaft

The shaft of the fibula is the long, slender part of the fibula extending between the fibular head proximally and the lateral malleolus distally. It lies lateral to the tibia and plays a minor role in weight-bearing but serves as a key site for muscle origins, tendon attachments, and interosseous membrane anchoring. Its importance lies in stabilizing the lateral compartment of the leg and providing attachment for multiple muscles and ligaments.

Surfaces and Borders

  • Surfaces: Lateral, medial, posterior

  • Borders: Anterior, posterior, interosseous (medial)

Joint and Ligament Attachments

  • Interosseous membrane: Attaches along the medial border, linking fibula to tibia

  • Crural interosseous ligaments: Reinforce distal shaft to tibia

  • Anterior/posterior tibiofibular ligaments: Attach distally but extend partly along shaft

Muscle Attachments

  • Lateral surface: Peroneus longus, peroneus brevis

  • Anterior surface: Extensor digitorum longus, extensor hallucis longus, peroneus tertius

  • Posterior surface: Tibialis posterior, soleus, flexor hallucis longus

  • Medial crest/interosseous border: Anchors interosseous membrane and tibialis posterior

Tendon Relations

  • Lateral compartment tendons: Peroneus longus and brevis run distally along shaft

  • Posterior compartment tendons: Tibialis posterior and flexor hallucis longus pass behind fibula

  • Anterior compartment tendons: EDL, EHL, and peroneus tertius cross anteriorly

Nerve Supply

  • Superficial peroneal nerve: Supplies lateral compartment muscles attaching to shaft

  • Deep peroneal nerve: Supplies anterior compartment muscles (EDL, EHL, peroneus tertius)

  • Tibial nerve: Supplies posterior compartment muscles related to shaft (tibialis posterior, soleus, FHL)

Arterial Supply

  • Peroneal artery: Primary supply to fibular shaft

  • Branches from anterior tibial and posterior tibial arteries contribute to periosteum and marrow

  • Nutrient artery: Enters middle third of shaft

Venous Drainage

  • Drains into peroneal, anterior tibial, and posterior tibial veins

Function

  • Provides attachment for multiple muscles and interosseous membrane

  • Contributes to stability of ankle and leg compartments

  • Minor role in weight transmission but essential for lateral support

Clinical Significance

  • Fractures: Common in trauma; often associated with tibial fractures

  • Stress fractures: Occur in athletes due to repetitive loading

  • Compartment syndrome: Fibula forms lateral wall of anterior and lateral compartments

  • Surgical relevance: Shaft used for vascularized bone grafts (fibular grafts in reconstruction)

MRI Appearance

  • T1-weighted images:

    • Marrow: intermediate-to-high signal depending on fat content

    • Cortical bone: uniform low signal (dark)

    • Fractures: linear low-signal lines across marrow and cortex

  • T2-weighted images:

    • Marrow: intermediate to high signal depending on fat content

    • Cortex: consistently dark (low signal)

    • Edema or stress fracture: bright hyperintense marrow with surrounding soft tissue edema

  • STIR:

    • Normal marrow suppressed (dark)

    • Pathology: stress fractures, bone bruises, periosteal reactions → bright hyperintense

  • Proton Density Fat-Saturated (PD FS):

    • Normal: uniform low-intermediate signal marrow, cortical rim low signal

    • Pathology: fractures or periosteal edema show bright signal

  • T1 Fat-Sat Post-Contrast:

    • Normal: uniform mild marrow enhancement

    • Stress fracture: linear non-enhancing line with peripheral enhancement

    • Osteomyelitis: diffuse marrow enhancement with cortical irregularity

MRI Arthrogram Appearance

  • Rarely performed for shaft itself

  • Surrounding joints (ankle, superior tibiofibular) may show contrast leakage if associated with ligament or capsule injury

CT Appearance

Non-Contrast CT:

  • Cortical bone: high-density, sharply delineated rim

  • Marrow: intermediate density relative to cortex

  • Excellent for detecting fractures, cortical irregularities, callus formation

  • Stress fractures: sclerotic bands or cortical thickening

  • Osteomyelitis: cortical destruction, sequestrum, or periosteal reaction

CT Arthrogram Appearance:

  • Contrast extravasation visible if cortical fracture extends to joint capsule

  • May show periosteal reaction or cortical breach associated with intra-articular extension

CT VRT 3D image

Fibula shaft 3d

MRI image

Fibula shaft MRI axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

CT image

Fibula shaft coronal ct image

CT image

Fibula shaft ct sagittal image