All of the following structures come in relation with the urethral crest which is situated in the prostatic pa of the urethra, EXCEPT:

Urethral crest is a midline longitudinal ridge on the posterior wall of the prostatic urethra. Prostatic sinus is a groove on each side of urethral crest. About 15-20 prostatic ducts open into the prostatic sinus to pour secretion of prostate into the urethra.Colliculus seminalis is an elevation at the middle of urethral crest. It has three openings on it, a median for prostatic utricle and lateral for ejaculatory duct of each side.Prostatic urethra is the proximal 3cm of the male urethra lying inside of the prostate gland. It pierces the base of prostate and leaves it at the apex. It lies near the anterior surface. It is the most dilatable and wide pa of the male urethra.Ref: Clinical Anatomy: (a Problem Solving Approach) By Neeta V. Kulkarn page 764.