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Tibialis anterior muscle

The tibialis anterior muscle is the largest and most medial muscle of the anterior compartment of the leg. It runs along the lateral surface of the tibia and inserts on the medial aspect of the foot. It is the primary dorsiflexor of the ankle and also inverts the foot. This muscle plays a critical role in gait, helping to clear the foot during the swing phase and controlling foot placement during stance.

It is commonly affected in conditions such as shin splints, compartment syndrome, tendon rupture, and nerve palsy (foot drop).

Synonyms

  • Anterior tibial muscle

  • TA muscle

  • Dorsiflexor of the foot

Origin and Insertion

  • Origin:

    • Lateral condyle of the tibia

    • Proximal two-thirds of the lateral surface of the tibial shaft

    • Interosseous membrane

    • Deep fascia of the leg

  • Course:

    • Fibers run vertically down the anterior leg

    • Tendon passes under the superior and inferior extensor retinacula

  • Insertion:

    • Medial cuneiform bone

    • Base of the first metatarsal bone (medial and plantar surfaces)

Nerve Supply

  • Deep peroneal (fibular) nerve (L4–L5)

Arterial Supply

  • Anterior tibial artery (primary)

  • Muscular branches from dorsalis pedis artery

Venous Drainage

  • Anterior tibial vein → popliteal vein → femoral vein

Function

  • Dorsiflexion of the ankle (primary function)

  • Inversion of the foot (synergist with tibialis posterior)

  • Maintains medial longitudinal arch of the foot

  • Stabilizes ankle and foot during walking and running

MRI Appearance

T1-weighted images:

  • Normal muscle shows low-to-intermediate signal intensity

  • Fat within intermuscular septa and surrounding tissue appears bright

  • Fatty degeneration (chronic) appears hyperintense

T2-weighted images:

  • Normal muscle shows low-to-intermediate signal

  • Edema, strain, or acute tear appears as bright hyperintense signal

STIR (Short Tau Inversion Recovery):

  • Normal muscle: low-to-intermediate signal

  • Pathology (strain, inflammation, compartment syndrome): bright hyperintensity

Proton Density Fat-Saturated (PD FS):

  • Normal muscle: low-to-intermediate signal

  • Muscle tear, tendinopathy, or edema: focal or diffuse bright hyperintensity

T1 Fat-Sat Post-Contrast:

  • Normal muscle: mild, homogeneous enhancement

  • Myositis, tumor, or infection: heterogeneous or diffuse enhancement

  • Abscess or complete tear with hematoma: rim enhancement with non-enhancing core

CT Appearance

Non-Contrast CT:

  • Normal muscle appears as homogeneous soft tissue density

  • Muscle borders defined by fat planes and tibia laterally

  • Hematoma appears as hyperdense regions

  • Chronic fatty replacement appears as low attenuation areas

Post-Contrast CT:

  • Normal muscle: mild uniform enhancement

  • Inflammatory or neoplastic changes: heterogeneous or intense enhancement

  • Abscess: central low attenuation with peripheral rim enhancement

  • Compartment syndrome: muscle enlargement, reduced definition of fascial planes

MRI image

Tibialis anterior muscle sag cross sectional anatomy 3T MRI radiology anatomy image-img-00000-00000

MRI image

Tibialis anterior muscle anatomy 3t mri image

MRI image

Tibialis anterior muscle anatomy

CT image

Tibialis anterior muscle axial ct image 0

CT image

Tibialis anterior muscle axial ct image 1

CT image

Tibialis anterior muscle axial ct image 2