[Location ] Localized in the erect sitting position or in the upward recumbent position, on the transverse crease of elbow, on the ulnar side of the tendon of m.biceps brachii (Fig.5)
 
[Regional Anatomy] Skin→subcutaneous tissue→the median nerve→brachialis. Superficial layer, the median elbow nerve and the medial branchial cutaneous nerve; deep layer, the brachial artery and vein, the arterial and venous network formed by the palmar side branch of the ulnar recurrent artery and vein, and the inferior collateral ulnar artery and vein, as well as the median nerve.