First Aid for the®: Obstetrics & Gynecology Clerkship, 5<sup>th</sup> Edition

Chapter 1: Reproductive Anatomy

INTRODUCTION

An adequate knowledge of the normal female anatomy is essential in obstetrics and gynecology. Each time a physician delivers a baby or performs a gynecologic surgery, he or she must be well versed in the anatomy of the region. This chapter will discuss the major structures of the pelvis. The major blood supply to the pelvis is from the internal iliac artery (hypogastric artery) and its branches. The lymphatics drain to the inguinal, pelvic, or para-aortic lymph nodes. The major parasympathetic innervation is via S2, S3, and S4, which forms the pudendal nerve. The major sympathetic innervation is via the aortic plexus, which gives rise to the internal iliac plexus.

VULVA

A 30-year-old G1P1 patient presents to the emergency department with a lump in the vulva and acute onset of pain for 2 days. The pain has gradually ↑, and she is unable to sit. She reports no fever, chills, nausea, or vomiting. She has no medical problems and takes no medications. On exam, the right labium majorum is swollen. A 4 × 4-cm fluctuant tender mass is palpated at the 8 o'clock position; no drainage is noted. What is the most likely diagnosis? What is the best treatment?

Answer: Bartholin's gland abscess. The best treatment is incision and drainage followed packing, or placement of Word catheter. If it recurs, consider marupialization. Can consider broad-spectrum antibiotics. If the patient is postmenopausal with recurrent Bartholin's abscess or cysts, consider carcinoma and obtain a biopsy.

The vulva consists of all structures visible externally from the pubis to perineum. It includes the labia majora, labia minora, mons pubis, clitoris, vestibule of the vagina, vestibular bulb, and the greater vestibular glands (see Figure 1-1). The vestibule itself contains the urethral opening, vaginal opening, bilateral Bartholin gland ducts, and bilateral Skene's (paraurethral) glands. The blood supply, lymphatics, and nerve supply of the vulva are detailed in Table 1-1.

Clitoris: Composed of a glans, a corpora, and two crura. Rarely exceeds 2 cm in length, and normal diameter is 1.5 cm. Homologuous to the male penis.
Bartholin glands: Located at 4 o'clock and 8 o'clock of the vaginal orifice and are typically nonpalpable. They function in secreting mucous to provide vaginal lubrication and are homologous to the bulbourethral glands in males.
Skene's glands: Ducts of these glands open on either side of the urethral orifice.

FIGURE 1-1.

(A) External female genitalia. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al. Williams Obstetrics. 23rd ed. New York: McGraw-Hill Education; 2010: Figure 2-2.) (B) Perineal anatomy. (Reproduced, with permission, from Ganti L. Atlas of Emergency Medicine Procedures. New York: Springer Nature; 2016.)