目的　为临床应用胸小肌移植重建拇对掌功能手术过程中神经吻接提供解剖学依据。　方法　解剖观测胸内侧神经及尺神经深支分支特点,比较相关神经有髓神经纤维数目，确定手术过程中神经吻接。　结果　胸内侧神经为胸小肌的主要支配神经，其在第3肋间隙近锁骨中线处入胸小肌，有髓神经纤维计数为（868±130）根；尺神经深支穿出内侧肌间隔后在第3、4掌骨间隙分别发出两明显肌支,其有髓神经纤维计数分别为（394±49）根、（708±78）根；P3L4(尺神经深支在第4掌骨间隙的分支，其分布于第3骨间掌侧肌和第4蚓状肌）与胸内侧神经、正中神经返支有髓神经纤维数目都比较接近。　结论　 胸小肌移植重建拇对掌功能手术中，在切取胸小肌时以胸内侧神经作为供体神经，以第3肋间隙与锁骨中线交点为标记寻找该神经；尺神经深支中P3L4肌支与胸内侧神经吻合最匹配。

Objective　To provide anatomic evidence for the reconstruction of the opposition function by pectoralis minor transplantation.　Methods　Dissecting and surveying on the medial pectoral nerves and the deep branches of the ulnar nerves were performed. The number of myelinated ulnar nerve fibers was compared for confirming the possible nerve fiber suture during the operation.　Results　The medial pectoral nerve was the dominant fiber for the innervation of pectoralis minor muscle, which pierced into the pectoralis minor at the midclavicular line from the third intercostal space, with the number of myelinated fibers of about 868±130. Through medial intermuscular septum, the deep branch of the ulnar nerve respectively gave rise to conspicuous branches in the fourth and third spatia interossea metacarpi. The numbers of myelinated fibers of these branches respectively were 708±78 and  394±49. The number of myelinated fibers of the P3L4 was as many as that of the medial pectoral nerve and the recurrent branch of median nerve.　Conclusions　During the operational process of reconstructing the opposition function by pectoralis minor muscle transplantation, the medial pectoral nerve can be taken as the donor nerve, which should be found at the junction of the midclavicular line and the third intercostal space. It's more match with each other by suturing the P3L4 with the medial pectoral nerve.