目的    为尺动脉腕上皮支降支小鱼际皮瓣修复手掌心皮肤缺损提供临床解剖学基础。 方法　自2018年5月至2019年5月，采用42侧上肢新鲜标本，其中28侧经肱动脉灌注红色乳胶并进行解剖，14侧经肱动脉灌注ABS后制作铸型标本，解剖观察尺动脉腕上皮支降支在小鱼际区的分支、走行、分布、交通和吻合形式，测量其外径。  结果    从豌豆骨到环、小指指蹼间画一连线，并将其分成3等份。结果显示每侧尺动脉腕上皮支降支发出14.5条分支，其中在远、中、近1/3段共发出皮支6.8支，交通支7.7支。各皮支在小鱼际浅筋膜内相互吻合，形成1~2级皮支链,皮支长(1.80±0.60)cm，直径(0.23±0.10)mm。交通支分别与深部的尺动脉掌深支、掌浅弓尺侧缘、尺侧指掌侧总动脉或小指尺掌侧动脉吻合，交通支长(1.60±0.50)cm，直径(0.16±0.06)mm。在近、远1/3段各有1~2支较大的交通支，是转位较理想的血管蒂。  结论    小鱼际皮瓣的尺动脉腕上皮支降支血管蒂位置恒定，皮瓣内皮支链丰富，皮肤结构与手掌心部位同源,是修复手掌心小面积皮肤缺损的较理想的供区之一。

Objective     To provide the clinical anatomical basis for repairing the palm skin defect with the hypothenar skin flap of the descending branches of supracarpal cutaneous branch of the ulnar artery. Methods    From May, 2018 to May, 2019, a total of 42 side upper extremities were used in the research. Twenty-eight side through brachial artery were perfused with red latex for anatomy, 14 side through brachial artery were perfused with ABS and eroded to be vascular cast mold. The branch, course, distribution, communication, outer diameter and anastomosis of the descending supracarpal cutaneous branch of the ulnar artery were anatomically observed and measured.    Results    A line from lentiform bone to the ring, webbing of the little finger was drawn and the line was divided into 3 equal sections. The descending branches of supracarpal cutaneous branch of the ulnar artery arised 14.5 branches, including 6.8 cutaneous branches and 7.7 communicating branches in the distal, middle and proximal 1/3 segments. The cutaneous branches anastomosed with each other to form 1-2 grade cutaneous branch chain in the superficial fascia of hypothenar. The length of cutaneous branches was (1.80±0.60) cm and the diameter of cutaneous branches was (0.23±0.10) mm. The communicating branches was anastomosis with deep branch of ulnar artery, the ulnar margin of superficial palmar arch, the common palmar digital artery or ulnar volar artery of little finger, respectively. The length of communicating branches was (1.60±0.50) cm and the diameter was (0.16±0.06) mm. There was one or two large communicating branches in the proximal and distal 1/3 segments, which can be used as an ideal flap vascular pedicle.   Conclusions     The hypothenar flap is an ideal selection to repair the small tissue defect of palm skin, for it has a constant position of the descending supracarpal cutaneous branch of the ulnar artery in the hypothenar skin flap, with abundant endothelium branch chains, and its skin structure is the homology with the center of the palm.