Anatomy & nerve supply of birth canal .pptx

Anatomy & nerve supply of birth canal .pptx

1. Anatomy & nerve supply of birth canal Dr.zikrullah mallick

2. Birth canal The passageway through which the  fetus  is expelled during parturition, leading from the uterus through the cervix and the vagina Also consists of vulva

3. VULVA Mons veneris Labia majora Labia minora Clitoris Vestibule Perineum

4. Mons veneris / Mons pubis : Pad of subcutaneous adipose connective tissue lying in front of pubis Covered with hair Labia majora : Vulva on either side bound by elevation of skin and subcutaneous tissue Join medially to form posterior commissure infront of anus Squamous epithelium Contain sebacious glands , sweat glands , hair folllicles

5. Labia minora : Two thin folds of skin, devoid of fat Anteriorly enclose clitoris Unite with each other in front and behind clitoris to form prepuce and frenulum Lower portion fuses across midline to form fourchette Between fourchette and vaginal orifice : Fossa navicularis Clitoris Small , cylindrical , erectile body 2.5cm Glans , body and two crura Squamous epithelium Rich nerve supply

6. Vestibule Triangular space : Anterior - clitoris Posterior - Fourchette Lateral -Labia minora 4 openings : Urethral , Vaginal orifice and hymen,opening of Bartholin ducts occasionally two skene ducts

7. Blood supply of Vulva Arteries Br. of internal pudendal artery Labial A., Transverse perineal A., A to vestibular bulb, deep & dorsal arteries to clitoris Br. of Femoral A : Superficial & deep external pudendal A Veins Internal pudendal vein Vesical/ vaginal venous plexuses Long saphenous vein

8. Nerve supply Ant-sup part Ilio inguinal & genital br. of genitofemoral N (L1,L2) Post- inf part Pudendal br. of post.cut . N of thigh (S123) In between Labial & perineal br.of Pudendal N (S234) Lymphatics Superf . Inguinal nodes Gland of Cloquet Ext. & Int. Iliac nodes

9. VAGINA Fibromuscular membranous sheath Excretory channel Organ of copulation Birth canal of parturition 45° with horizontal 2.5cm diameter distensibility

10. Walls Ant : 7cm Post : 9cm 2 lateral walls Fornices : Ant : shallow 2 lateral Post : deep

11. Structures: Mucous coat – Stratified squamous epithelium without glands Submucous layer of loose areolar vascular tissues Muscular layer : inner circular, outer longitudinal Fibrous coat:endopelvic fascia Secretions:Acidic (4-5 pH) Doderlein’s bacilli Oestrogenic activity

12. Blood Supply of vagina Arteries Cervicovaginal br. of uterine A Vaginal A Middle rectal A Internal pudendal Anastomose---form 2 azygos arteries ant and post Veins drain into: Internal iliac V Internal pudendal V

13. Lymphatics : Upper one third : External iliac group Middle one third upto hymen : Internal Iliac group Lower one third : superficial inguinal group Nerve supply Lower one third pain sensitive- pudendal nerve nerve through the inferior rectal and posterior labial branches of the perineal nerve The upper two-thirds of the vagina are pain insensitive and are supplied by sympathetic LI, L2 and parasympathetic segments S2, S3 nerves derived from the inferior hypogastric and uterovaginal plexuses

14. UTERUS Hollow, pyriform muscular organ in pelvis Position: anteversion & anteflexion uterus dextrorotated cervix levorotated Measurements 7.5cm long 5cm wide, 2.5 cm thick Weight : 30-40gm

15. PARTS OF UTERUS Body/Corpus Fundus : 1.5 cm Body proper: 3.5 cm cornua Isthmus Constricted part 0.5 cm Between anatomical & histological internal os (of Aschoff )

16. Cervix 2.5cm, cylindrical Supravaginal & infravaginal ( portio vaginalis ) parts Cervical canal External os opening shape Secretion: alkaline & thick, rich in fructose, NaCl and mucoprotein

17. RELATIONS OF THE UTERUS Anterior Above int.os : uterovesical pouch Below int.os : separated from UB by loose areolar tissue Posterior Pouch of Douglas with coils of intestine

18. Lateral Broad ligament Mackenrodt’s ligament Uterine A & ureter

19. Structures Body Perimetrium : Invests entire organ except on lateral borders Myometrium : Smooth muscle fibres held by connective tissue Endometrium : mucous lining Cervix : Squamocolumnar junction at external os

20. Blood supply Arteries: Uterine A Ovarian & Vaginal A. Veins drain into Internal iliac veins

21. Nerves Sympathetic Motor : T5 & T6 Sensory : T10 – L1 Somatic distribution of uterine pain : area of abdomen T10 to L8 Parasympathetic Pelvic N ( S2,3,4) : both motor & sensory : ends in ganglia of Frankenhauser

22. Supports of the uterus Primary Muscular or active : Pelvic / Pelvic floor Perineal body Urogenital diaphragm Fibromuscular or mechanical : Uterine axis Pubocervical ligament Transverse cervical – Mackenrodt Uterosacral ligament Round ligament of uterus Secondary : Broad ligament Uterovesical fold of peritoneum Rectovaginal fold of peritoneum

23. Fallopian tubes 10 cm in length 3 layers : Serous Muscular Mucous membrane

24. Blood Supply Arteries Uterine A Ovarian A Veins Through pampiniforn plexus into ovarian veins Lymphatics Para-aortic nodes Nerve supply Uterine & ovarian nerves

25. Ovary Oval in shape 3cm in length , 2cm in breadth and 1cm in thickness Relations of ovary Mesovarium / anterior border Posterior border : free Medial surface : fimbrial part of the tube Lateral surface : in contact with ovarian fossa on lateral pelvic wall

26. Blood Supply Arterial : Ovarian A Veins : Through pampiniform plexus to form ovarian V. Lt. Renal Vein IVC Lymphatics Para-aortic nodes Nerve supply Sympathetic supply from T10 along ovarian A.

27. Thank you