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Posterior ulnar recurrent artery

The posterior ulnar recurrent artery (PURA) is a major branch of the ulnar artery, arising just distal to the origin of the anterior ulnar recurrent artery. It ascends posteriorly and medially toward the medial epicondyle of the humerus, deep to the flexor-pronator muscles, and contributes significantly to the periarticular arterial anastomosis of the elbow joint.

The PURA is larger and longer than the anterior ulnar recurrent artery and plays a crucial role in collateral circulation, particularly when the brachial artery is compressed or occluded. It supplies blood to the flexor carpi ulnaris, flexor digitorum profundus, and the posterior aspect of the elbow joint.

Synonyms

  • Posterior branch of the ulnar recurrent artery

  • Inferior posterior ulnar collateral branch (historic term)

Origin, Course, and Termination

  • Origin: Arises from the ulnar artery, typically 2–5 cm below its origin in the cubital fossa, distal to the anterior ulnar recurrent branch.

  • Course:

    • Ascends proximally and medially, deep to the flexor digitorum profundus and flexor carpi ulnaris.

    • Passes posterior to the medial epicondyle of the humerus, running with the ulnar nerve in the posterior compartment of the elbow.

    • Curves around the medial epicondyle, joining the posterior aspect of the elbow’s arterial network.

  • Termination:

    • Ends by anastomosing with the superior ulnar collateral artery (branch of the brachial artery) and small branches of the inferior ulnar collateral artery around the olecranon and medial epicondyle.

Relations

  • Anteriorly: Flexor digitorum profundus and flexor carpi ulnaris muscles

  • Posteriorly: Medial head of triceps brachii and olecranon process

  • Medially: Ulnar nerve and medial epicondyle of humerus

  • Laterally: Brachialis and medial intermuscular septum

  • Superiorly: Elbow joint capsule and anastomotic arterial network

Branches

  • Muscular branches: To flexor carpi ulnaris, flexor digitorum profundus, and medial head of triceps

  • Articular branches: To posterior and medial aspects of the elbow joint capsule

  • Anastomotic branches: Join the superior and inferior ulnar collateral arteries and small posterior radial recurrent branches

Function

  • Arterial supply: Provides blood to the posteromedial elbow region, including the flexor-pronator muscle group and joint capsule

  • Collateral circulation: Contributes critically to the posterior elbow anastomosis, maintaining perfusion during elbow flexion or brachial artery compression

  • Clinical role: Important compensatory pathway in arterial occlusion, trauma, or reconstructive surgery

Clinical Significance

  • Collateral importance: Integral to the ulnar and brachial artery anastomotic system around the elbow

  • Vascular trauma: May be injured in fractures of the medial epicondyle or penetrating wounds

  • Surgical relevance: Important consideration during ulnar nerve decompression and ulnar artery harvest procedures

  • Aneurysm or pseudoaneurysm: May present as a pulsatile mass behind the medial epicondyle

  • Stenosis or thrombosis: Can reduce collateral flow, relevant in ischemic or embolic disease

  • Imaging value: Key structure in angiographic evaluation of the ulnar collateral network

MRI Appearance

  • T1-weighted images:

    • Normal artery: flow void (dark signal) due to rapid blood flow

    • Perivascular fat: bright, outlining the vessel

    • Thrombosed or slow-flow segments: intermediate intraluminal signal

    • Vessel wall thickening (vasculitis or trauma): intermediate-to-bright rim signal

  • T2-weighted images:

    • Flowing blood: dark signal (flow void)

    • Wall abnormalities or thrombus: intermediate-to-bright

    • Surrounding muscles and soft tissues well delineated

    • Aneurysmal dilation: focal bright ring signal surrounding dark lumen

  • STIR:

    • Normal artery: dark flow void

    • Pathology: hyperintense perivascular signal in edema, hematoma, or inflammation

  • Proton Density Fat-Saturated (PD FS):

    • Artery: dark, smooth tubular flow void

    • Vasculitis or thrombosis: bright or inhomogeneous wall signal

    • Good for identifying perivascular soft-tissue edema

  • T1 Fat-Sat Post-Contrast:

    • Normal lumen: bright homogeneous enhancement

    • Occlusion: segmental non-enhancement with visible collaterals

    • Vasculitis: concentric mural enhancement

    • Pseudoaneurysm: peripheral rim enhancement with central non-enhancing lumen

MRA (Magnetic Resonance Angiography) Appearance

  • Normal:

    • Appears as a tortuous, enhancing vessel ascending posteriorly from the ulnar artery and curving around the medial epicondyle.

    • Best visualized on contrast-enhanced 3D MRA or time-of-flight (TOF) sequences.

  • Pathology:

    • Stenosis: segmental signal narrowing or reduced flow intensity.

    • Aneurysm: focal bulbous signal enhancement.

    • Thrombosis or occlusion: focal signal dropout with collateral visualization.

    • Vasculitis: mural enhancement and thickened arterial wall.

CT Appearance

Non-Contrast CT:

  • Vessel lumen not directly visualized unless calcified.

  • Perivascular soft-tissue density and adjacent muscle anatomy evident.

  • Chronic vascular calcifications: linear or curvilinear hyperdense foci along arterial course.

Post-Contrast CT (standard):

  • Artery appears as a small enhancing tubular vessel coursing posterior to the medial epicondyle.

  • Helps distinguish artery from adjacent veins and tendons based on enhancement timing and position.

  • Detects wall thickening, pseudoaneurysm, hematoma, or perivascular inflammatory changes.

CTA (CT Angiography) Appearance

  • Normal:

    • Clearly demonstrates a contrast-filled posteriorly directed artery branching from the ulnar artery and looping around the medial epicondyle.

    • Optimal visualization in arterial-phase CTA with thin multiplanar reconstructions.

  • Pathology:

    • Stenosis or occlusion: focal narrowing or cutoff of contrast flow.

    • Aneurysm or pseudoaneurysm: focal saccular or fusiform dilation with homogeneous contrast filling.

    • Collateral network: multiple enhancing fine vessels around the medial elbow, joining the superior ulnar collateral artery.

    • Vasculitis: irregular arterial contour with concentric wall enhancement.

MRI image

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

MRI image

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