1. Anatomy of the female pelvis
and
vaginal birth

2. Take a look at the bony pelvis you have been given.
View it from the front.
In the following slides, the bony landmarks will be described.

4. Innominate bone

5. Sacrum

6. Coccyx

7. Sacroiliac joint

8. Sacrococcygeal joint

9. Symphysis pubis

10. Ischial spine

11. Ileopectineal line

12. Obturator foramen

13. Pubic arch

14. Sacral promontory

15. Anterior foramina

16. Now look at the pelvis from one side.
In the following slides, more landmarks will be shown.
You will also see how the pelvis is orientated when a woman is standing up straight.

17. Anterior superior iliac spine
Symphysis pubis
Vertical plane

18. Ileum
Pubis
Ischium

19. Acetabulum
Obturator foramen

20. Look at the pelvis from the front again.
In the following slides, you will be shown a little more anatomy.
Look at the position of the sacrotuberous and sacrospinous ligaments.

21. Sacrotuberous ligament

22. Sacrospinous ligament

23. Look at the pelvis from behind.
Look at the position of the sacrotuberous and sacrospinous ligaments.
These delineate the greater and lesser sciatic foraminae.

25. Sacrospinous ligament

26. Sacrotuberous ligament

27. Greater sciatic foramen
Lesser sciatic foramen

28. We are now going to add in some muscles.
You will see piriformis from front and back.
You will see obturator internus from the back.

29. Piriformis

30. Piriformis

31. Obturator internus

32. We are now going to add in blood vessels and nerves.
Look at the pelvis from the front again.

35. Common Iliac A
Internal Iliac A

36. External Iliac A

37. Common Iliac V
Internal Iliac V 37

38. The Lumbosacral Plexus

39. Sciatic nerve

40. Pudendal nerve

41. Obturator nerve

42. Look at the pelvis from the side.
We will look at the muscles and ligaments on the side wall of the pelvis.
You will see where the levator ani muscles originate.
You will also see the critical dimensions of the pelvis.

44. Sacrotuberous ligament

45. Sacrospinous ligament

46. Obturator canal

47. Obturator internus
Muscle
Covered by
Fascia

48. Pudendal canal

49. Line of attachment of levator ani

50. Critical pelvic dimensions
Pelvic inlet

51. Critical pelvic dimensions
Pelvic midplane

52. Critical pelvic dimensions
Pelvic outlet

53. Female
Male
Pelvic inlet
Pelvic outlet
Pelvic cavity
Pubic arch

54. Look at the pelvis from the front again.
Imagine a ‘coronal’ plane through the middle of the pelvis.
You will see the rectum coming through the pelvis.
You will see where the levator ani muscles originate.
You will see which structures form the pelvic diaphragm.

55. Iliac crest
Pelvic brim
Ischial tuberosity

56. Rectum

57. Obturator
Internus
With Fascia

58. Levator ani
Plus coccygeus
Makes
Pelvic diaphragm

59. There are some structures above the pelvic diaphragm.
There are some structures below the pelvic diaphragm.

60. Peritoneum

61. Subperitoneal space

62. Contains:
Pubocervical
Trans cervical
Sacrocervical
Ligaments

63. everything under pelvic diaphragm
Perineum
everything under pelvic diaphragm

64. Ischiorectal fossae

65. Now look at the pelvis from below.
Look at the layout of the bones and the ligaments.
They define the pelvic outlet.

66. Obturator membrane
Obturator canal

67. Pubic arch
Symphysis pubis
Inferior pubic ramus
Ischial ramus

68. Ischial tuberosity
Sacrotuberous ligament
Sacrum / coccyx

69. Pelvic outlet

70. Urogenital triangle
Anal triangle

71. Keep looking at the pelvis from below.
Imagine the anatomy above the pelvic diaphragm.
The following slides show the structures encountered as you descend through the pelvis.

72. Bladder
Above the
Pelvic diaphragm
Cervix
Rectum

73. Pubocervical ligament
Above the
Pelvic diaphragm

74. Above the
Pelvic diaphragm
Transverse cervical ligament

75. Above the
Pelvic diaphragm
Sacrocervical ligament

76. Pelvic diaphragm
Levator ani:
Pubococcygeus
Iliococcygeus
Ischiococcygeus
Coccygeus

77. Keep looking at the pelvis from below.
Imagine the anatomy as you descend below the pelvic diaphragm.
The following slides show the structures encountered as you continue to descend through the pelvis.

78. Urogenital diaphragm
Superior layer
of fascia

79. Urogenital diaphragm
Sphincter urethrae
Deep transverse peroneal muscles

80. Perineal membrane

81. Structures in
Superficial pouch
Clitoris & crus
Bulb of vestibule
Vestibular glands

82. Muscles in
Superficial pouch
Ischiocavernosus
Bulbospongiosus
Supl transverse peroneal muscles

83. Perineal body

84. Keep looking at the pelvis from below.
You have now reached the most superficial level.

85. Labium majus
Labium minus

86. Mons pubis
Prepuce of clitoris
Vestibule
vagina
Fourchette

87. Here is the female abdomen and pelvis viewed from one side.
The structures shown should now be familiar to you.

89. Peritoneum

90. Sacrocervical ligament
Pubocervical ligament

91. Pelvic diaphragm

92. Urogenital diaphragm

93. Look at its anatomical relations.
Here is the rectum.
Look at its anatomical relations.

94. Rectum
Sacrum
Perineal body
Anococcygeal body

95. Puborectalis
Deep
Superficial
Subcutaneous

96. Take your fetal skull and view it from above.
Note the near central position of the anterior fontanelle.

97. parietal eminence
coronal sutures
frontal bones
lambdoid sutures
occiput
anterior fontanelle
posterior fontanelle
saggital suture

98. The following slides will demonstrate the orientation of the fetal skull as it passes through the pelvis in normal labour.

99. the head flexes as the uterus contracts
passenger
the head flexes as the uterus contracts
the head descends and engages in the pelvis
the leading part approaches the ischial spines

100. passenger the occiput starts to rotate anteriorly
the occiput reaches the pelvic floor (levator ani)
internal rotation continues to achieve an occipito-anterior position

101. the occiput clears the symphysis pubis the head extends to deliver
passenger
the occiput clears the symphysis pubis
the head extends to deliver

102. the head sits on the maternal perineum
passenger
the head sits on the maternal perineum

103. the fetal head realigns itself with the fetal shoulders - restitution
passenger
the fetal head realigns itself with the fetal shoulders - restitution

104. the head therefore continues to rotate - external rotation
passenger
the shoulders contact the pelvic floor and rotate so that the bisacromial diameter lies in an anteroposterior orientation
the head therefore continues to rotate - external rotation