persistent median artery of the forearm

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The persistent median artery of the forearm is an accessory artery that arises from the ulnar artery in the proximal forearm and is a persistent embryological remnant of the axial artery that usually regresses by eight weeks gestation.

Epidemiology

It is present in ~10% (range 2.2-23%) of the population.

Gross anatomy

The persistent median artery of the forearm is a continuation of the common or anterior interosseous artery and accompanies the median nerve as it passes through the forearm and carpal tunnel.

It is unilateral ~67% of the time and is associated with anomalous median nerves ~70% (range 63-80%) of the time - most commonly bifid median nerves followed by high division of the median nerve. The persistent median artery is contained within the epineurium of the normal or bifid median nerve.

The persistent median artery is located on the ulnar aspect of the normal median nerve (see Case 1) but if the median nerve is bifid the persistent median artery is located between the two nerve bundles (see Case 2).

Related pathology

The persistent median artery can be a cause of carpal tunnel syndrome and is important to recognize if imaging is performed pre-operatively as it may be damaged during surgery. If it is not recognized intra-operatively due to tourniquet use subsequent damage may be a cause of post-operative bleeding.