阴茎及会阴浅层肌的解剖学特点及与勃起功能关系

Association of penis and perineal superficial muscle with erectile function

目的:观察男性坐骨海绵体肌、球海绵体肌及阴茎血管的构筑特点,探讨其与勃起生理相关的解剖学因素。方法:实验于2004-07/2005-03在郑州铁路职业技术学院医学分院解剖学实验室完成。18例阴茎均取自死后3～5h内的尸体(年龄18～63岁),流浪死亡者(无名无亲属)及自愿捐献者(捐献者或捐献者家属知情并同意)。应用血管铸型法对18例成人阴茎制作血管铸型标本,再分别取下每具尸体两侧坐骨海绵体肌和球海绵体肌进行观察。用天平测量肌质量、用游标卡尺测量肌长(肌纤维起点最近端至止点最远端的距离)及用量角器测量羽状角(肌矢状切面上测量肌纤维与肌腱之间所形成的夹角)等指数。结果:阴茎海绵体内纵行的动脉发出无数树状分支,其中部分分支为毛细血管,此毛细血管汇合后注入白膜下静脉丛;部分形成螺旋动脉,与海绵窦相交通。引流海绵窦血液的窦后小静脉相互融合形成白膜下静脉丛,再汇合形成导静脉。坐骨海绵体肌肌质量(2.13±0.26)g,肌长(7.36±0.16)cm,羽状角(5.20±0.27)°;球海绵体肌肌质量(2.14±0.58)g,肌长(7.25±0.76)cm,羽状角(28.63±0.18)°。结论:副交感神经作用使阴茎动脉血管扩张,阴茎静脉和静脉分流支的管腔部分闭合,由于静脉回流受阻,引起阴茎海绵体和尿道海绵体充血膨胀,导致阴茎勃起。勃起的阴茎由于海绵体外坚韧的白膜的限制和会阴浅层肌尤其是坐骨海绵体肌的收缩,进一步压迫阴茎静脉,阻碍血液回流,勃起得以维持。球海面体肌收缩在协助勃起、缩窄和缩短尿道,帮助排尿和射精时,需要会阴浅横肌收缩加强会阴中心腱的稳定;坐骨海绵体肌收缩使硬勃起期的阴茎硬度增强,两肌协同作用,使勃起期的阴茎保持中立状态。

AIM： To observe the structural features of male ischiocavemous muscle, bulbocavemous muscle and penis vessels, so as to explore the related anatomic factor of erectile physiology. METHODS： The experiment was conducted in the anatomic laboratory of Medical School of Zhengzhou Railway Vocational Technical College between July 2004 and May 2005. Eighteen penises were obtained from the corpse died within 3-5 hours and aged 18-63 years, wandering dead person without name or relatives and voluntary donors with informed consent. The casting samples were made by vascular corrosion cast method, and the bilateral ischiocavemous muscle and bulbocavemous muscle were harvested for observation. The muscular mass, muscular length （distance from the proximal end of muscle fiber to the distal end） and pinnate angles （angle between muscle fiber and muscle tendon from the muscular sagittal section） ware measured with balance, sliding caliper and conimeter, respectively. RESULTS： Many dendritic branches derived from the longitudinal dorsal arteries in corpora cavemosa of penis; part of the branches were blood capillary, which stretch to the venous plexus below albuginea; part of them formed helicine arteries and connected with cavemous sinus. Post-sinusoidal small veins drained cavemous sinus blood became confiuenced and form venous plexus below albuginea, and finally generated emissary vein. The muscular mass, length, and pinnation angles of average ischiocavemosus was （2.13±0.26） g, （7.36±0.16） cm, （5.20±0.27）°; the muscular mass and length, and the pinnation angles of average bulbospongiosus was （2.14±0.58） g, （7.25±0.76） cm, （28.63±0.18）°. CONCLUSION： Parasympathetic nerve causes arteda penis anapetia, and partial lumina occlusion of penile vein and venous branches; moreover, the venous return is interrupted, which results in the congestive expansion of cavernous body of penis and urethra, and finally the penile erection. As the tenacious albugineous limitation out of cavernous body and contraction of ischiocavemosus of perineal superficial muscle continue oppress the penile vein, and interfere the blood backstreaming, the erectile penis is maintained. Bulbospongiosus could assist erection, shorten urethra, help urination and ejaculation when the contraction of perineal superficial muscle strengthens the stability of central tendon of perineum; Ischiocavemosus helps strengthen the rigidity of perils in rigidity phase. The cooperation of these two muscles could make the penis keep neutrality state.