9.4 Perineum Anatomy and Functions

Male & Female Perineum

• Anatomy of male and female perineum includes various structures pertinent to urogenital functions.

• Diagrams and diverse labeled structures are crucial for understanding anatomy.

Pelvis and Perineum

• Greater Pelvis: Contains abdominal cavity, lower gastrointestinal tract.

• Lesser Pelvis: Pelvic cavity housing bladder, lower ureters, reproductive organs, and rectum.

• Perineum: anus, external genetalia

• Divisions of the Pelvis and Perineum

• Determined by bony landmarks (iliac alae and pelvic inlet).

• Contents of perineum are separated from the true pelvis by pelvic diaphragm and fascial layers.

• False Pelvis Components: Ileum, cecum, appendix, sigmoid colon.

• True Pelvis Components: Distal ureters, urinary bladder, rectum, female (vagina, uterus), male (ductus deferens/prostate).

PERINEUM in both genders
• Pubic symphysis (ant) to coccyx (post)
– transverse line between ischial tuberosities
• urogenital triangle – “closed” by fascia
• anal triangle
• perineal body (centre point)

Deep and Superficial Perineal Pouches

• Deep Pouch: Contains perineal membrane, pelvic diaphragm, and structures crossing the diaphragm.

• Superficial Pouch: Contains ischiocavernosus & bulbospongiosus muscles; aids in erectile function.

Muscles of Deep and Superficial Perineal Pouches support the perineal body and pelvic floor muscles

Muscles of the Pelvic Floor and Perineum

• Levator Ani: Supports pelvic organ position and assists in defecation. (Perineal membrane and deep and superficial perineal pouch)

• Coccygeus: Forms the posterior part of pelvic diaphragm.

• Perineal Muscles: Important for support and stability; includes external urethral sphincter, deep/superficial transverse perineal muscles, bulbospongiosus.

Perineal Blood Supply and Innervation

• Blood Supply: Branches from internal iliac arteries and femoral arteries (e.g., pudendal artery).

• Venous Drainage: Tributaries leading to internal iliac veins

• Nerve Supply:

  • Pudendal Nerve: Somatic innervation (L1-S4).

  • Parasympathetic Nerves: Responsible for erection (S2-S4) somatic

  • Sympathetic Nerves: Control ejaculation and thermoregulation (L1-L2).

• Lymphatic drainage: iliac nodes, inguinal nodes

Summary

• Knowledge of anatomical structures is essential for clinical applications, particularly relating to reproduction and urinary functions.

• Understanding of neural control is crucial for recognizing physiological events such as erection and ejaculation.

• Anatomy study integrates blood supply, nerve supply, and muscle functions pertaining to male and female reproductive systems.