Superficial brachial artery: a possible cause for idiopathic median nerve entrapment neuropathy

Nerve entrapment syndromes occur because of anatomic constraints at specific locations in both upper and lower limbs. Anatomical locations prone to nerve entrapment syndromes include sites where a nerve courses through fibro-osseous or fibromuscular tunnels or penetrates a muscle. The median nerve (MN) can be entrapped by the ligament of Struthers; thickened biceps aponeurosis; between the superficial and deep heads of the pronator teres muscle and by a thickened proximal edge of flexor digitorum superficialis muscle. A few cases of MN neuropathies encountered are reported to be idiopathic. The superficial branchial artery (SBA) is defined as the artery running superficial to MN or its roots. This divergence from normal anatomy may be the possible explanation for idiopathic MN entrapment neuropathy. This study presents three cases with unilateral presence of the SBA encountered during routine undergraduate dissection at the University of Johannesburg. Case 1 - SBA divided into radial and ulnar arteries. Brachial artery (BA) terminated as deep brachial artery. Case 2 - SBA continued as radial artery (RA). BA terminated as ulnar artery (UA), anterior and posterior interosseous arteries. Case 3 - SBA continued as UA. BA divided into radial and common interosseous arteries. Arteries that take an unusual course are more vulnerable to iatrogenic injury du-ring surgical procedures and may disturb the evaluation of angiographic images during diagnosis. In particular, the presence of SBA may be acourse of idiopathic neuropathies.