Anatomy of the Male Genital Urinary System

Introduction to Male Genital Anatomy

  • Presenter: Hunter, Junior Anatomy Fellow

  • Location: Colorado Campus

  • Acknowledgements: Thank Doctor Moffett for providing slides

  • Learning Objectives:

    • Understand the anatomy of the male genitourinary (GU) system

    • Discuss functions of anatomical structures

    • Review blood supply and nerve innervation

    • Explain clinical correlates associated with dysfunction

Overview of Male GU Structures

  • Key Anatomical Structures:

    • Scrotum and testes

    • Prostate and seminal vesicles

    • Male urethra

    • Penis

  • Importance of Lymphatic Flow

    • Specific lymphatics related to male GU anatomy

Bony Landmarks and Surface Anatomy

  • Ischial Ramus:

    • Located on the lateral posterior aspect

    • Important for locating the crus of the penis

  • Crus of the Penis:

    • Located medial and anterior to the ischial ramus

  • Bulb of the Penis:

    • Found midline between pelvic body tendons

    • Serves as the base of the penis

  • Pubic Symphysis:

    • Attachment between two pubic bones, anterior midline

  • Scrotal Raphe:

    • Skin folding at the base of the scrotum, distinguished surface anatomy

Scrotum and Testes Anatomy

  • Scrotum Composition:

    • Accumulation of skin, muscle, and fascia

    • Contains the spermatic cord

  • Spermatic Cord Components:

    • Testicular Artery: Supplies blood to testes

    • Pampiniform Venous Plexus: Network of veins with interchanged terminology

    • Testicular Veins: Named interchangeably as part of the plexus

  • Testes Functions:

    • Gonad for sperm creation

    • Contains Epididymis for sperm storage

    • Ductus Deferens: Pathway for sperm exiting the scrotum

Anatomical Layers of the Scrotum

  • Significant Anatomical Layers (From Superficial to Deep):

    • Skin

    • Dartos Fascia and Muscle: Derived from Scarpa's fascia

    • External Spermatic Fascia: From external abdominal oblique aponeurosis

    • Cremaster Muscle: From internal abdominal oblique

    • Internal Spermatic Fascia: From transversalis fascia

    • Tunica Vaginalis: Parietal and visceral layers from peritoneum

Scrotal Contents and Clinical Correlates

  • Hydrocele:

    • Serous fluid accumulation in the scrotum

    • Caused by improper closure of the peritoneal cavity or pressure on veins

  • Hematocele:

    • Blood accumulation due to trauma

  • Transillumination Test:

    • Light passed through scrotum to identify fluid nature

    • Positive for hydrocele, negative for hematocele

Testes Developmental Pathway

  • Sperm Pathway from Testes:

    1. Seminiferous Tubules →

    2. Straight Tubules →

    3. Ret testes →

    4. Efferent Ductules →

    5. Epididymis

  • Clinical Correlate:

    • Spermatocele: Epididymal cyst that is the accumulation of sperm

  • Differentiation from Hydrocele:

    • Spermatocele presents as a third testicle

Blood Supply of Scrotum and Testes

  • Asymmetrical Venous Drainage:

    • Left Testicular Vein drains into Left Renal Vein

    • Right Testicular Vein drains into Inferior Vena Cava

  • Summary of Blood Supply:

    • Testicular Arteries: Branch from abdominal aorta

  • Testicular Torsion:

    • Twisting of vessels leading to ischemia and severe pain

Additional Structures: Prostate and Seminal Vesicles

  • Prostate Location:

    • Inferior to the bladder

    • Appearance resembles a walnut

  • Seminal Vesicles:

    • Posterior to the bladder

    • Shape compared to chewed gum

  • Functions:

    • Nutrient supply and protection for sperm during ejaculation

    • Alkaline secretions to neutralize acidity

Anatomy of Prostate Components

  • Prostate Zones:

    • Fibromuscular Zone: Important for ejaculation and retrograde prevention

    • Central Zone: Glandular tissue contributing to seminal fluid

    • Transitional Zone: Associated with benign prostatic hyperplasia (BPH)

    • Peripheral Zone: Common site for prostatic carcinoma

Blood Supply to Prostate and Seminal Vesicles

  • Internal Iliac Artery: Main supply

    • Anterior division supplies vesicles and prostate

    • Umbilical artery gives rise to superior vesicle artery

    • Inferior Vesicle Artery: Supplies seminal vesicles and prostate

  • Prostatic Arteries: Supply capsule and urethra

Male Urethra and Its Divisions

  • Major Divisions:

    • Prostatic Urethra: Connects bladder to prostate

    • Membranous Urethra: Shortest segment, contains external sphincter

    • Spongy Urethra: Passes through penis

External Genitalia: Penis Anatomy

  • Crus and Bulb of the Penis:

    • Crus attached to ischial ramus, bulb is midline

  • Names for the Distal Structures:

    • Crus → Corpus Cavernosum

    • Bulb → Corpus Spongiosum

  • Frenulum and Foreskin: Distal structures of the penis

Muscles Associated with External Genitalia

  • Ischiocavernosus Muscle: Found over the corpus cavernosum

  • Bulbospongiosus Muscle: Found over the corpus spongiosum

Ligaments Supporting Penis

  • Suspensory Ligament of the Penis: Associated with external oblique aponeurosis

  • Fundiform Ligament: Formed from Scarpa's fascia

Clinical Correlates Related to Catheterization

  • Improper catheterization can lead to blood pooling

    • Could involve deep or superficial perineum, leading to swelling or dysfunction

Vaginal Drainage and Lymphatics

  • Testes and Epididymis Drainage:

    • Go to lumbar nodes

  • Inferior bladder, prostate, and seminal vesicles: Drain to internal iliac nodes

  • Superficial Inguinal Nodes: Drain superficial structures

  • Deep Inguinal Nodes: Drain glans penis

Conclusion

  • Importance of understanding male GU anatomy to appreciate clinical conditions

  • Open for questions and further clarifications on topics discussed.