Zvara P, Carrier S, Kour N W, Tanagho E A
Department of Urology, University of California School of Medicine, San Francisco.
Br J Urol. 1994 Aug;74(2):182-7. doi: 10.1111/j.1464-410x.1994.tb16583.x.
To study the nerve supply of the striated urethral sphincter.
The pelvis from six formalin-fixed male cadavers was dissected.
Cadaveric dissection revealed that both the intrinsic and extrinsic segments of the urethral rhabdosphincter receive their innervation from sacral roots S2-S4. The nerve fibres travel to their final destination via both the pudendal nerves and the nerve branches of the sacral roots. The terminal branches of the pudendal nerve enter the sphincteric area from the perineum. They separate shortly after they cross the ischial spine and run further ventromedially. Small branches approach the sphincter after their division from the dorsal nerve of the penis. The course of the pudendal nerve and its branching on the perineum are quite consistent. The pelvic branches travel inside the pelvis above the levator ani muscle. Among the cadavers the number of branches varied markedly, as did their site of termination (2.3 to 3.9 cm from the striated urethral sphincter). A substantial nerve approaching the sphincter from inside the pelvis was found. After it divided from the S2, S3 sacral roots it ran separately, initially just lateral to the fibres of the pelvic plexus and then on the dorsolateral surface of the rectum. In its terminal segment it dived into the levator ani muscle and terminated in the striated urethral sphincter.
We believe that the nerve supply to the striated urethral sphincter consists of branches from both the pudendal nerve and the 'extrapudendal' nerves that run above the levator ani muscle inside the pelvis. The variations in the course of the latter are remarkable.
研究尿道横纹括约肌的神经支配。
解剖6具经福尔马林固定的男性尸体的骨盆。
尸体解剖显示，尿道横纹括约肌的固有段和外在段均接受来自骶神经根S2 - S4的神经支配。神经纤维通过阴部神经和骶神经根的分支到达其最终目的地。阴部神经的终末支从会阴进入括约肌区域。它们在越过坐骨棘后不久分开，进一步向腹内侧走行。小分支从阴茎背神经分出后接近括约肌。阴部神经在会阴的走行及其分支相当一致。盆支在肛提肌上方的盆腔内走行。在尸体中，分支数量差异显著，其终止部位也不同（距尿道横纹括约肌2.3至3.9厘米）。发现一条从盆腔内接近括约肌的粗大神经。它从骶神经根S2、S3分出后单独走行，起初在盆腔丛纤维的外侧，然后在直肠的背外侧表面。在其终末段，它潜入肛提肌并终止于尿道横纹括约肌。
我们认为，尿道横纹括约肌的神经供应由阴部神经和在盆腔内肛提肌上方走行的“阴部外”神经的分支组成。后者走行的变异显著。
