单项选择题
A．sciatic nerve B．inferior gluteal nerve C．obturator nerve D．pudendal nerve E．median nerve
A．hepatic vein B．renal vein C．left common iliac vein D．right testicular vein E．hepatic portal vein
A．prostatic portion of urethra B．membranous part of urethra C．where it crosses superior aperture of lesser pelvis D．where it pierces into the unrinary bladder E．internal urethral orifice