Prostatic urethra

The prostatic urethra, the widest and most dilatable part of the urethra canal, is about 3 cm long.

It runs almost vertically through the prostate from its base to its apex, lying nearer its anterior than its posterior surface; the form of the canal is spindle-shaped, being wider in the middle than at either extremity, and narrowest below, where it joins the membranous portion.

A transverse section of the canal as it lies in the prostate is horse-shoe-shaped, with the convexity directed forward.

The keyhole sign, in ultrasound, is associated with a dilated bladder and prostatic urethra.

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  Lobes of prostate
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  Zones of prostate
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  Structure of the penis
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  Vertical section of bladder, penis, and urethra.
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  Vesiculæ seminales and ampullæ of ductus deferentes, seen from the front.

This article incorporates text in the public domain from page 1234 of the 20th edition of Gray's Anatomy (1918)

• Anatomy image: malepel2-4 at the College of Medicine at SUNY Upstate Medical University
• Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna
• Anatomy photo:44:05-0201 at the SUNY Downstate Medical Center - "The Male Pelvis: The Prostate Gland"
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