Gynae Anatomy Integration - Female External Genitalia

Overview of Videos

1. Female External Genitalia (Vulva/Pudendum)

   • Comprehensive exploration of the vulva and its structures.

2. Female Internal Genital Organs

   • Detailed study of the ovaries, uterus, and vagina.

3. Surgical Anatomy of the Pelvis

   • Focus on anatomical considerations relevant to pelvic surgeries.

Female External Genital Organs (Vulva/Pudendum)

Model Presentation

The lecture employs a clay model to provide a tangible representation of the female external genitalia, enhancing understanding of spatial relationships and anatomical structures.

Mons Pubis

• Hair-bearing area overlying the pubic symphysis, serving as a protective cushion for the pubic bone.

• Contains subcutaneous fat, contributing to its rounded appearance and providing insulation.

Labia Majora (Outer Lips)

• Outer, hair-bearing lips containing sweat, sebaceous, and apocrine glands, essential for protection and lubrication.

• Posteriorly meet at the posterior commissure, forming the lower boundary of the vulva.

• Anteriorly, at the anterior one-third, the round ligament and processes vaginalis attach, contributing to structural support and embryonic development.

• Homologous to the male scrotum, sharing embryological origins and structural similarities.

Labia Minora (Inner Lips)

• Inner lips, typically not as visible, lying within the labia majora and surrounding the vestibule.

• Medial part: Non-keratinized stratified squamous epithelium, providing a moist, protective surface.

• Lateral part: Keratinized stratified squamous epithelium, offering a tougher, more resistant outer layer.

• Hartz line: Separates the keratinized and non-keratinized epithelium, marking a transition in tissue type and function.

• Posteriorly meet at the fourchette, the point where the labia minora converge behind the vaginal opening.

• Anteriorly enclose the clitoris, forming the prepuce (superiorly) and frenulum (inferiorly), providing protection and support.

• Do not contain hair, and have only sebaceous glands, distinguishing them from the labia majora.

Clitoris

• Erectile organ, homologous to the male penis, responsible for sexual sensation and arousal.

• Normal length: $2$ to $2.6$ cm, though size can vary among individuals.

• Anteriorly enclosed by labia minora forming the prepuce and frenulum, which contribute to its sensitivity and protection.

• Lining: Stratified keratinized squamous epithelium, similar to the skin.

Vestibule

• Space bounded by the clitoris anteriorly, labia minora laterally (Hartz line), and fourchette posteriorly, containing several important openings.

• Contains six openings:

  1. Urethra: The opening through which urine is expelled from the body.

  2. Paraurethral glands (Skene's glands) at 1:00 and 11:00 position, homologous to the prostate gland in males and contributing to lubrication.

  3. Introitus (vaginal opening), covered by the hymen (typically perforate), the entrance to the vagina.

  4. Bartholin duct openings just outside the introitus at 4:00 and 8:00 position (or 5:00 and 7:00), secreting lubricating mucus.

• Bartholin glands are located in the groove between labia majora and labia minora, ensuring proper lubrication during sexual activity.

• Bartholin glands are homologous to bulbourethral glands (Cowper's glands) in males and provide lubrication during intercourse, aiding in comfortable sexual function.

Fossa Navicularis

• Depression between the introitus and the fourchette, a common site for minor skin irritations or infections.

Clinical Correlation

• Blockage of Bartholin gland ducts leads to swelling between labia majora and minora, not typically in the vaginal wall, which can cause discomfort and pain.

• Ducts open at the junction of anterior two-thirds and posterior one-third, an important consideration during surgical procedures or examinations.

Diagram of Female External Genitalia

Key Structures Labelled

• Mons Pubis (Mons Venereum): Hair-bearing area, providing a protective cushion.

• Clitoris: Homologous to male penis, central to female sexual sensation.

• Labia Majora: Outer lips, protecting the inner structures.

• Posterior Commissure: Where labia majora meet posteriorly, forming the lower boundary.

• Labia Minora: Inner lips, surrounding the vestibule.

• Fourchette: Where labia minora meet posteriorly, a sensitive area.

• Prepuce: Fold above the clitoris, providing protection.

• Frenulum: Fold below the clitoris, contributing to sensitivity.

• Vestibule: Area between clitoris, fourchette, and labia minora: Contains six openings

  • Urethral opening: For urine excretion.

  • Paraurethral glands (Skene's glands): Contributing to lubrication.

  • Introitus: Opening of the vagina; covered by the hymen.

  • Openings of Bartholin ducts: For mucus secretion.

• Fossa Navicularis: Area between introitus and fourchette, susceptible to irritation.

Terminology

• Vulva and Pudendum are other names for the female external genitalia, used interchangeably in medical contexts.

Mons Pubis/Mons Venereus

• Rounded fat pad ventral to the pubic symphysis, covered by hair, protecting the pubic bone and providing cushioning.

• Pubarche: Appearance of pubic hair at puberty, dependent on androgens, marking the beginning of sexual maturation.

• Tanner staging: Hair appears on Mons pubis in Tanner stage three, a key indicator in assessing pubertal development.

Labia Majora

• Posteriorly meet at posterior commissure, forming the lower boundary of the vulva.

• Subcutaneous layer similar to the anterior abdominal wall with Camper's fascia (superficial fatty layer) and Colles' fascia (deep membranous layer/superficial perineal fascia), influencing the spread of infections.

Colles' Fascia Attachments and Clinical Significance

• Anteriorly: Continuous with the anterior abdominal wall, allowing potential spread of infection.

• Laterally: Attached firmly to ischiopubic rami, limiting lateral spread of infection.

• Posteriorly: Attached to the perineal membrane, defining the boundaries of the superficial perineal space.

• Clinical Significance:

  • Infection from the superficial perineal space can spread to the anterior abdominal wall but not to the thigh due to the attachments of Colles' fascia, guiding clinical interventions.

• Anteriorly, at the anterior one third part structures attach:

  • Round Ligament (RL): Homologous to the gubernaculum of testes; originates from the angle of the uterus, passes through the inguinal canal, and attaches to the labia majora, providing structural support.

  • Processes vaginalis: A remnant of the processus vaginalis, which can sometimes persist.

• Contains all types of glands and hair follicles, contributing to their protective and sensory functions.

• Lymphatic drainage is into superficial inguinal lymph nodes, important for understanding the spread of vulvar cancers.

Differential Diagnosis for a Mass on Labia Majora

• Leiomyoma arising from the round ligament, a benign smooth muscle tumor.

• Persistent processes vaginalis, a cystic mass due to incomplete closure.

• Breast tissue along the distal milk line, ectopic breast tissue that can present as a mass.

• Indirect inguinal hernia, protrusion of abdominal contents into the labia majora.

Labia Minora

• Posteriorly meet at the fourchette, forming the posterior boundary of the vestibule.

• Hartz line separates the medial (non-keratinized stratified squamous epithelium) from the lateral part (keratinized stratified squamous epithelium), influencing their respective functions.

• No sweat, apocrine, or ecrine glands, and no hair follicles, but abundant sebaceous glands are present, providing lubrication to the area.

• Anteriorly splits into two folds: Prepuce and frenulum, protecting and supporting the clitoris.

Clitoris

• Three parts: Glans, body, and two crura, each contributing to its erectile function and sensitivity.

• Glans drains into deep inguinal lymph nodes (lymph node of Cloquet or Rosenmuller lymph node), a key consideration in cancer staging.

• Body and crura drain into superficial inguinal lymph nodes, then deep inguinal lymph nodes, influencing the patterns of lymphatic spread in vulvar cancers.

• Homologous to the penis in males, erectile and highly vascular, enabling sexual arousal and sensation.

• Normal length: $2$ to $2.5$ cm; > $4$ cm indicates clitoromegaly, which is associated with ambiguous genitalia, requiring further investigation.

Ambiguous Genitalia

• Genitalia where the sex is unclear, requiring careful evaluation and management.

• Clitoromegaly is a sign, prompting further investigation.

• Requires further evaluation and is covered in disorders of sexual development, emphasizing the complexity of these cases.

Vestibule

• Area bounded by clitoris anteriorly, labia minora laterally, and fourchette posteriorly; contains six openings, each with specific functions:

  • Urethra: For urine excretion.

  • Paraurethral glands (Skene's glands): Contributing to lubrication.

  • Introitus: Opening of the vagina; covered by the hymen.

  • Openings of Bartholin ducts: For mucus secretion.

Fossa Navicularis

• Shallow depression between the vaginal orifice (introitus) and fourchette, a site prone to minor skin irritations.

Paraurethral Glands (Skene's Glands)

• Homologous to prostate glands, sharing similar developmental origins.

• Located at 1:00 and 11:00 position, contributing to urethral lubrication.

• Skene's cyst: Anterolateral to urethral opening, a potential site for cyst formation.

Bartholin Gland (Greater Vestibular Gland)

• Pea-sized glands, two in number, of racemose variety; normally non-palpable, unless inflamed or cystic.

• Located in the superficial perineal pouch between labia minora and majora at 4:00 or 8:00 position, ensuring strategic placement for lubrication.

• Gland lined by columnar epithelium; duct lined by transitional epithelium and stratified squamous non-keratinized epithelium, influencing their secretory functions.

• Homologous to Cowper's glands (bulbourethral glands) in males, reflecting shared embryological origins.

• Function: Secretes alkaline mucus at the time of intercourse, neutralizing vaginal acidity and facilitating sperm motility.

• Ducts open in the vestibule outside the hymen at the junction of the anterior two-thirds and posterior one-third, allowing for targeted lubrication.

Bartholin Cyst Presentation

A 23-year-old female complains of a 3 cm intermittent, painless mass on her vulva, aggravated by intercourse, resolving on its own.

• The mass is located between labia majora and minora, just outside the introitus, not in the wall of the vagina, aiding in proper diagnosis.

Bartholin Cyst Management

If a Bartholin cyst is happening in a female who is more than 40 years or who is postmenopausal, if there is a solid mass and if the solid mass is fixed to some structure, then the next step should be biopsy of the cyst wall because the cancer is suspected.

Else if the condition mentioned above is not met, then the below process should be followed.

• Recent management (updates):

  • Symptomatic:

  • Incision and drainage (I&D), irrespective of size, providing immediate relief.

  • If it recurs, repeat I&D (total of three times), following a step-wise approach.

  • If recurrence persists after three I&Ds, then marsupialization is indicated, addressing persistent issues.

  • Asymptomatic:

  • <3 cm: No treatment needed, adopting a conservative approach.

  • ≥3 cm: Incision and drainage, preventing potential complications.

Marsupialization Exteriorizes the lining of the gland to prevent recurrence by stitching it with the lining of the vestibule, creating a new, permanent opening.

• Bartholin abscess is also treated by I&D followed by insertion of Word catheter, promoting continuous drainage.

• The most common organism in Bartholin abscesses is E. coli, followed by gonorrhea, guiding antibiotic therapy.

Bartholin Cancer

• Most common variety: adenocarcinoma, an important consideration in diagnosis.

• The most common symptom: a vulval mass followed by dyspareunia, prompting clinical evaluation.

• Honen criteria: Classification of Bartholin gland cancer, aiding in staging and treatment planning.

General Vulva Anatomy

Blood Supply

• Internal pudendal artery, providing the primary arterial supply.

Nerve Supply

• Pudendal nerve (S2-S4), responsible for sensory and motor innervation.

Lymphatic Drainage

• Superficial inguinal lymph node (sentinel lymph node) → deep inguinal lymph nodes (femoral nodes), affecting the spread of vulvar cancers.

• In vulvar cancer, inguinal femoral lymph node dissection is performed, an important surgical procedure.

• Clitoris drains into superficial inguinal lymph node, except the glans, which drains directly into deep inguinal lymph node (lymph node of Cloquet/Rosenmuller), influencing patterns of metastasis.

Homologous Organs Table

Organs in male and female with the same embryological origin: