Nerve Supply of female genital tract edited.pptx

This ppt describes the nerve supply of female reproductive system and its applied aspect.

1. Nerve Supply of female genital tract Dr. Shivani Siddhpura M.S.ObsGyn

2. Middle Rectal Ovary & Fallopian Tube

3. Pudendal Nerve It a mixed nerve, mainly supplying the pelvic floor & perineum. Nerve roots  – anterior rami of S2-S4 Sensory  – innervates the external genitalia of both sexes and the skin around the anus, anal canal and perineum Motor  – innervates various pelvic muscles ( bulbospongiosus , ischiocavernous & levator ani), the external urethral sphincter and the external anal sphincter.

4. Course of Pudendal Nerve It descends and passes between the piriformis and  ischiococcygeus muscles. It leaves the pelvis through the lower part of the  greater sciatic foramen . It then crosses the sacrospinous ligament (close to its insertion to the ischial spine) ,  and then re-enters the pelvis through the lesser sciatic foramen. Then it accompanies the internal pudendal artery and vein, coursing  anterosuperiorly through the  pudendal canal  (Alcock’s canal – a structure formed by the fascia of the obturator internus muscle). Inside the pudendal canal, the nerve divides into branches: inferior rectal nerve, perineal nerve, & the dorsal nerve of the penis or clitoris.

5. Innervation of vulva The vulva receives sympathetic and parasympathetic nervous supply. To describe the sensory distribution, the vulva can be divided into anterior and posterior sections: Anterior  – ilioinguinal nerve (L1), genital branch of the genitofemoral nerve (L1,2) Posterior  – pudendal nerve, posterior cutaneous nerve of the thigh (S1,2,3) The clitoris and the vestibule also receive parasympathetic innervation from the  cavernous nerves  – derived from the uterovaginal plexus. Motor Fibres to Vulva comes from pudendal nerve (S2,3,4).

6. Applied anatomy of pudendal nerve Pudendal Nerve Entrapment syndrome: Seen post childbirth commonly. Also seen due to horse-riding, bicycle/motor bike riding. Caused due to sacrospinous/ sacrotuberous ligament trauma Requires MRI for diagnosis. Management: Nerve Block. Inferior Cluneal nerve is the inferior part of Posterior Femoral Cutaneous Nerve of Thigh (S1,2,3). Genitofemoral Nerve is a mixed branch of anterior rami of Lumbar Plexus (L1L2).

7. Pudendal Nerve Block The pudendal nerve is blocked near ischial spine for pain relief during instrumental deliveries & stitching of episiotomy.

8. Inferior hypogastric plexus The  inferior hypogastric plexus , also known as the pelvic plexus or pelvic ganglion, is a paired collection of nerve fibers situated on each side of the  rectum  in males, or on sides of the rectum and  vagina  in females. The inferior hypogastric plexus is formed by the contributions from the  pelvic splanchnic nerves , sacral splanchnic nerves, and  superior hypogastric plexus  along with the afferent fibers from pelvic viscera. The hypogastric plexus contains both  parasympathetic  and  sympathetic   nervous fibers. The main  function  of this plexus is to supply the  pelvic and perineal organs .  In females, it supplies the  ovary ,  fallopian tubes , uterus, cervix and vagina. 

9. Innervation of vagina Innervation is predominantly from the autonomic nervous system through the inferior hypogastric plexus via the uterovaginal plexus: Sympathetic through thoraco-lumbar (T12-L1) and parasympathetic through pelvic splanchnic nerves (S2-S4). Only the inferior 1/5 of the vagina receives somatic innervation. This is via a branch of the  pudendal nerve , the  deep perineal nerve .

10. Innervation of uterus Sympathetic nerve fibers of the uterus arise from the  uterovaginal plexus . This largely comprises the  anterior  and  intermediate  parts of the  inferior hypogastric plexus . Parasympathetic fibers of the uterus are derived from the  pelvic splanchnic nerves (S2-S4). The cervix is largely innervated by the  inferior  nerve fibers of the  uterovaginal plexus. The afferent fibers mostly ascend through the  inferior hypogastric plexus   to enter the spinal cord via  T10-T12  and  L1  nerve fibers. The uterus and cervix are insensitive to touch, heat, cutting and pain but are sensitive to dilatation.

11. Innervation of fallopian tubes The uterine tube receives sympathetic innervation from the  superior hypogastric plexus  (T10-L2) via the  hypogastric nerve . Parasympathetic innervation stems from the  pelvic splanchnic nerves  and the  vagus nerve .  Sensory afferent fibres run from  T11- L1 . Tubes are sensitive to handling and the pain is referred to lower abdomen & mid-inguinal region.

12. Innervation of ovaries The ovaries are innervated by the  ovarian nervous plexus  which receives fibers from the aortic, renal and hypogastric ( superior,inferior ) plexuses. Sympathetic fibers are derived from the  lesser splanchnic nerves  (T10-T11). Parasympathetic innervation arises from the  pelvic splanchnic nerves  (S2-S4).  The nerves reach the ovaries via the  suspensory ligament of the ovary , to enter the ovary at the hilum.

13. Quick Revision of Nerve supply Genital Organ Nerve Root Value Uterine Body Pelvic splanchnic nerves (parasympathetic) Superior hypogastric Inferior hypogastric (sympathetic) (sensory & motor) S2,3,4 T11,12, L1 Cervix, Upper Vagina Pelvic plexus (parasympathetic) S 2,3,4 Lower Vagina, Perineum Pudendal Nerve (sensory & motor) S 2,3,4 Labia majora, Perineum Inguinal Nerve & Genital Branch of Genitofemoral Nerve L1 L2

14. obstetric analgesia

15. Paracervical block B locks transmission of pain impulses at the paracervical  ganglion. Provides satisfactory pain relief during the first stage of labour .

16. Epidural Analgesia

17. Spinal anaesthesia