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Posterior tibial artery

The posterior tibial artery (PTA) is one of the terminal branches of the popliteal artery, arising at the lower border of the popliteus muscle. It descends in the posterior compartment of the leg, accompanied by the posterior tibial veins and tibial nerve, supplying deep posterior leg muscles and continuing into the foot as the medial and lateral plantar arteries.

It plays a vital role in lower limb perfusion, particularly in the posterior compartment and plantar aspect of the foot. The posterior tibial artery is of major clinical importance, as its pulse at the ankle (posterior to the medial malleolus) is routinely used to assess peripheral circulation.

Synonyms

  • PTA

  • Medial posterior leg artery

  • Tibialis posterior artery

Origin, Course, and Termination

  • Origin: From the bifurcation of the popliteal artery at the lower border of the popliteus muscle.

  • Course:

    • Passes deep to the soleus arch, descending between the superficial and deep posterior compartments.

    • Lies posterior to the tibialis posterior and flexor digitorum longus muscles.

    • Runs with the tibial nerve and posterior tibial veins within the tarsal tunnel posterior to the medial malleolus.

  • Termination: Divides into the medial and lateral plantar arteries beneath the flexor retinaculum of the ankle.

Relations

  • Superiorly: Popliteus muscle (at origin)

  • Inferiorly: Flexor retinaculum and tarsal tunnel contents

  • Anteriorly: Tibialis posterior, flexor digitorum longus

  • Posteriorly: Gastrocnemius, soleus

  • Laterally: Posterior tibial veins and tibial nerve

  • Medially: Deep fascia and skin near the medial malleolus

Branches

  • Circumflex fibular artery

  • Peroneal (fibular) artery

  • Nutrient artery to tibia

  • Muscular branches to soleus, tibialis posterior, flexor digitorum longus

  • Medial malleolar and calcaneal branches

  • Terminal branches: Medial and lateral plantar arteries

Function

  • Major arterial supply to posterior compartment of leg and plantar foot

  • Nutrient flow to tibia and associated musculature

  • Anastomotic contribution to collateral circulation of the ankle and heel

  • Pulse point for assessing peripheral arterial flow and diagnosing peripheral artery disease (PAD)

Clinical Significance

  • Palpation site: Posterior to the medial malleolus (important in vascular assessment)

  • Peripheral arterial disease (PAD): Reduced or absent PTA pulse indicates distal ischemia

  • Aneurysm/stenosis: Can occur in trauma or atherosclerosis

  • Entrapment: Compression in the tarsal tunnel can affect blood flow to the plantar foot

  • Surgical relevance: Used as a recipient vessel in lower limb bypass grafting and reconstructive flaps

  • Imaging: Evaluation by MRI/MRA/CTA for stenosis, thrombosis, aneurysm, or entrapment

MRI Appearance

  • T1-weighted images:

    • Artery lumen: low signal (flow void) due to flowing blood

    • Surrounding muscles: intermediate signal intensity

    • Fat planes and fascia: bright signal

  • T2-weighted images:

    • Lumen remains dark (flow void) unless flow is slow or turbulent (then appears hyperintense)

    • Wall thickening or thrombus: intermediate-to-high signal intensity

    • Adjacent muscle: intermediate signal, darker than T1

  • STIR:

    • Suppresses fat signal, improving vessel conspicuity

    • Edematous changes or perivascular inflammation appear hyperintense

  • Proton Density Fat-Saturated (PD FS):

    • Arterial wall: low to intermediate signal

    • Pathology (thrombus, mural inflammation): bright signal

    • Excellent for assessing wall edema or vessel wall thickening

  • Normal T1 FS Axial Post-Contrast:

    • Lumen: uniformly bright enhancement with gadolinium contrast (normal flow)

    • Wall: smooth and thin; no focal thickening

    • Surrounding tissues: no abnormal enhancement

    • Artery–vein differentiation enhanced due to timing of contrast bolus

    • Pathology: Stenosis or occlusion appears as focal luminal narrowing or lack of enhancement; mural thrombus shows eccentric non-enhancing area

MR Angiography (MRA)

  • Demonstrates continuity, caliber, and patency of the artery from popliteal bifurcation to ankle.

  • Contrast-enhanced MRA clearly show vessel lumen and branches.

  • Normal MRA:

    • Lumen: bright signal due to flowing blood

    • Wall: thin, smooth contour

    • Stenosis: focal signal drop or tapering

    • Occlusion: absence of flow-related enhancement

    • Aneurysm: focal dilation with preserved signal intensity

CT Appearance

Non-Contrast CT:

  • Artery seen as soft-tissue attenuation structure adjacent to tibial nerve and veins

  • Surrounding calcified plaques (if present) easily visualized

  • Not ideal for flow assessment

Post-Contrast CT (standard):

  • Lumen enhances brightly with iodinated contrast

  • Wall calcifications, atherosclerotic plaques, or mural thrombus visible

  • Soft-tissue relationship and branching pattern well defined

CT Angiography (CTA)

  • Normal CTA:

    • Artery lumen: bright opacification with smooth, regular margins

    • Wall: thin, symmetric

    • Branches: peroneal, nutrient, and plantar arteries visible

    • 3D reconstruction: provides clear visualization of tibial arterial anatomy

  • Pathology:

    • Stenosis: focal luminal narrowing or wall irregularity

    • Occlusion: complete lack of contrast filling distal to lesion

    • Aneurysm: focal saccular or fusiform dilation with full contrast enhancement

    • Dissection: intimal flap dividing true and false lumens

MRI image

Posterior tibial artery axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI image

Posterior tibial artery axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000_00001

MRI image

Posterior tibial artery axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000_00002

CT image

Posterior tibial artery axoal 0

CT image

Posterior tibial artery ct axial 1

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Posterior tibial artery ct sagittal image