Male Urethra Anatomy

Male Urethra

• The male urethra is approximately 18-20 cm long, extending from the internal urethral orifice in the urinary bladder to the external opening (meatus) at the end of the penis.
• The urethra is divided into two main parts: posterior urethra and anterior urethra.

Posterior Urethra

• The posterior urethra is relatively short, lying in the pelvis, proximal to corpus spongiosum, and is acted upon by urogenital sphincter mechanisms.
• It is composed of three segments: preprostatic, prostatic, and membranous segments.

Anterior Urethra

• The anterior urethra is relatively long, surrounded by corpus spongiosum, and functions as a conduit.
• It is composed of bulbar (proximal component) and penile parts.

Prostate

• The prostate is a small, walnut-shaped gland that surrounds the urethra.
• It produces a fluid that helps nourish and transport sperm.
• The prostate is divided into four lobes: two lateral lobes, an anterior lobe, and a posterior lobe.
• It is responsible for producing a fluid that makes up about 30% of the volume of semen.

Other Male Reproductive Organs

• Testes: Produce sperm and testosterone.
• Epididymis: A coiled tube located on the back of the testes where sperm mature and are stored.
• Vas Deferens: Tubes that carry sperm from the epididymis to the urethra.
• Seminal Vesicles: Glands that produce a fluid that nourishes and protects sperm.
• Prostatic Urethra: The part of the urethra that passes through the prostate.
• Membranous Urethra: The shortest part of the urethra, passing through the pelvic floor.
• Penile Urethra: The part of the urethra that passes through the penis.
• Glans Penis: The head of the penis.
• Prepuce: A fold of skin that covers the glans penis.

Muscles of the Abdomen and Pelvis

• Muscles of the Abdomen: Important for core stability, internal organ support, breathing, and trunk rotation.
• Muscles of the Pelvis: Essential for proper bladder and bowel control, as well as supporting the organs in the pelvic cavity.

Clinical Anatomy

• Common injuries in the abdominal and pelvic regions include strains and tears.
• The peritoneal fascia is vulnerable to compromise due to trauma.

Anatomy of the Urethra

• The urethra is surrounded by a coat and inner lining of mucous membrane that is continuous with that of the bladder.
• The outer sheath is composed of striated muscle (external urethral sphincter), controlled by the somatic nervous system.
• The inner sheath is composed of smooth muscle (internal sphincter).
• Smooth muscle fibers, perpendicular to the axis of the urethra, are the innermost layer.
• The urethra receives its innervation from the pelvic splanchnic nerves and the pudendal nerve.