THE BONY PELVIS for all Midwifery students

Bony pelvis

1. THE BONY PELVIS BY Ms Alice Osei 1

2. Objectives By the end of this lecture, students should be able to: Describe the anatomy of the female pelvis and its importance in the practice of obstetrics and gynecology. To describe the divisions and measurement of the pelvis. To describe the types of pelvis and their effects on labour or child birth. 2

3. The Bony Pelvis The bony pelvis serves as a protective bony ring encircling the reproductive organs bladder and rectum in a female It varies in shape and size . The shape influences the passage of the fetus during labour . Therefore a knowledge of the bony pelvis helps the midwife in the following: To assess the progress of labour . To detect deviation from normal and refer to the doctor 3

4. The Bony Pelvis To recognize the abnormalities that must require medical attention. 4

5. Situation, Shape and Size of the Bony Pelvis Situation: It articulates with the 5 th lumber vertebra above and the head of each femur in the right and left acetabulum below. Shape: It is similar to the bony basin. Size: The Pelvic girdle is the largest formation of bone in the body. 5

6. Pelvic Bones There are 4 pelvic bones. One sacrum One coccyx Two innominate (hip) bones. 6

7. The Normal Female Pelvis 7

8. The Sacrum It is a wedge-shaped bone consisting of 5 fused vertebrae The upper border of the first sacral vertebra juts forward and it is known as the sacral promontory The anterior surface of the sacrum is concave and it is referred to as hollow of the sacrum . In a gynaecoid pelvis,the concavity of the sacrum allows fetal head to descend as well as play a part in directing the fetus through the pelvis around the curve of carus 8

9. The Sacrum cont . The sacral promontory is the central part of the upper boarder of the first sacral vertebra that protrudes the hollow of the sacrum. Laterally, the sacrum extends into a wing or ala . .Four pairs of foramina or holes pierce through the sacrum and through these nerves from the cauda equina emerge to supply the pelvic organs Posterior surface is roughened to receive attachment of muscles . 9

10. The Sacrum Cont. Superiorly, the sacrum articulates with the last lumbar vertebra and inferiorly with the coccyx. NOTE: Below the 2 nd sacral vertebrae spinal anesthesia could be given to relieve pain during labour or for surgery. 10

11. Diagram of the sacrum 11

12. The Coccyx It consist of four fused vertebrae which is triangular in shape It articulates with the sacrum. It has slight degree of movement. During the birth of the fetus, the coccyx moves backwards to help enlarge the pelvic outlet, which assists the fetus passage to facilitate a vaginal birth. 12

13. The Coccyx Cont. The coccyx also provides attachment points for the pelvic ligaments, the muscle fibres of the anal sphincter and the ischiococcygeus muscle of the pelvic floor. 13

14. The Coccyx 2/5/2023 14

15. Diagram of the Innominate Bone 15

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17. The Innominate bone Each innominate bone is composed of 3 parts: The ilium The ischium The pubic/ pubis They meet in a cup- shaped depression which is known as the acetabulum MS ALICE OSEI 17

18. The Innominate bone cont. The illium : This is the flared upper part and the bone of the flank. The ilium forms the upper 2/5 th of the acetabulum. The upper margin is the iliac crest and this is where the hand rest when is placed on the hip.. Where the iliac crest ends in front is known as the anterior superior iliac spine. MS ALICE OSEI 18

19. The Illium cont. About 2.5 cm below the anterior superior iliac spine is a small projection called the anterior inferior iliac spine. posterior superior iliac spine is located on the posterior portion of the ilium On a living person , the posterior superior iliac spine are marked by small dimples on the left and right just above the cleft of the buttocks. 19

20. The ischium This forms the lowest part of the innominate bone and forms the lower 2/5 th of the acetabulum.(an L-shaped bone that connects to the ilium posteriorly and to the pubis anteriorly) It has a large prominence known as ischial tuberosity which is the thickened portion of the body of the ischium. Ischial tuberosity is the part which the body rest on when sitting. Ischial spine is a sharp projection of bone found behind and a little above the tuberosity. In labour station of the head fetal head is estimated in relation to the ischial spines 20

21. The pubic bone/ Pubis This is the smallest and the anterior portion of the innominate bone. It forms the lowest 1/5 th of the acetabulum. The two pubic bones unites anteriorly by a pad of cartilage known as the symphysis pubis. It has a body and two oar-like projections known as the superior and inferior rami. 2/5/2023 MS ALICE OSEI 21

22. The pubic bone/ Pubis cont. The two inferior pubic rami forms the pubic arch . The angle of the pubic arch should not be less than 90 . The space enclosed by the body of the pubic bone, the rami and the ishium is called the obturator foramen In life it is covered by obturator membrane through which the obturator nerve and blood vessels pass leading to the thigh   22

23. Pelvic Joints There are four pelvic joints namely: Two sacroiliac joints One Symphysis pubis One Sacrococcygeal joint MS ALICE OSEI 23

24. The Pelvic joints cont . 1 . Two sacroiliac joint : They are the strongest joints of the body. They join the sacrum to the ilium and thus connect the spine to the pelvis There is slight synovial movements at the point where the ilium joins the first sacral vertebrae under normal conditions but during pregnancy the rate of movement increases under the hormone progesterone and relaxin. 24

25. The Pelvic joints cont. 2 . The Symphysis Pubis: It is formed at the junction of the two pubic bones and united by a pad of cartilage. There is increase mobility and size in this cartilage in the last months during pregnany 2/5/2023 MS ALICE OSEI 25

26. The Symphysis Pubis MS ALICE OSEI 26

27. The Pelvic joint cont . 3. The Sacrococcygeal joint: It is formed between the lower end of the sacrum and the upper boarder of the coccyx. It also has supporting ligament. Normally, movement of this joint is very little but increases with the influence of progesterone during pregnancy . MS ALICE OSEI 27

28. The Sacrococcygeal Joints Cont . This makes the coccyx tips backwards at the sacrococcygeal when the fetus is being born. NOTE: The extra movements at the joints during pregnancy may cause local aching . Again there is a little widening of the joints during labour and delivery and this is referred to as the “give” of the pelvis. MS ALICE OSEI 28

29. MS ALICE OSEI 29

30. The Pelvic Ligaments These are strong fibrous tissue which binds the pelvis bones together and strengthens the pelvic joints. The sacroiliac ligaments: This is the strongest ligament of the body. It passes infront of and behind each sacroiliac joint 2. The interpubic ligament : Named according to their position they binds the symphysis pubis anterior, superior and inferior. 30

31. The Pelvic Ligament cont . 3. Sacrococcygeal ligament: This join the sacrum to the coccyx 4. The Sacrotuberous ligaments: This is a strong ligament that runs from the lower border of the sacrum to the ischial tuberosity. 5. The Sacrospinous ligaments: This stretches from the lower border of the sacrum to the ischial spines. NB: These two ligaments cross the sciatic notch and form the posterior wall of the pelvic outlet . They are important in midwifery. MS ALICE OSEI 31

32. The Pelvic Ligament cont . Obturator membrane: This is the ligament that occupies the obturator foramen , except for small opening which allows the passage of blood vessels, lymphatics and nerves. The inguinal or Pourpart’s ligament: It runs from the anterior superior iliac spine to the body of the pubis. 32

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34. Divisions Of The Pelvis The pelvis is divided into 2 parts: The false pelvis: This lies above the pelvic brim. It is formed by the flared out portion of the iliac bones and protects the abdominal organs. It is of no significance in obstetrics. 34

35. Divisions Of The Pelvis Cont . The True pelvis: The part of the pelvis significant in childbirth or it is a bony canal through which the fetus must pass during birth. The true pelvis has a brim, cavity and the outlet and it forms the Curved Canal through which the fetus must pass to be born. 35

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37. The Pelvic Brim/ Inlet The brim is round in shape except where the promontory of the sacrum projects into it. The promontory and the wings of the sacrum forms its posterior wall/borders and the pubic bones form the anterior border. The midwife must be familiar with the landmarks of the brim which are 8 in number from back to front: The promontory of the sacrum The ala of the sacrum MS ALICE OSEI 37

38. The Pelvic Brim/ Inlet cont. Sacroiliac joint. Iliopectineal line which is the edge formed at the inward aspect of the ilium Iliopectineal eminence which is the roughened area where the superior ramus of the pubic bone meets the iium Inner border of the superior pubic ramus. The body of the pubic bone. Upper boarder of the symphysis pubis. 38

39. The pelvic brim/ inlet BERNICE OFOSU NTIAMAOH 39

40. The Cavity It is round or circular in shape in a gynaecoid pelvis It extends from the brim of the pelvis above to the pelvic outlet below. The posterior wall is formed by the hollow of the sacrum/curve of the sacrum and measures 12 cm in length. The anterior wall is formed by the symphysis pubis and the pubic bones and it measures 4cm in length. 40

41. The Cavity cont. Its lateral walls are the sides of the pelvis which are mainly covered by obturator internus muscle. The boundaries of the cavity are: The hollow of the sacrum The sacroiliac joints sacrospinous ligament ischia 41

42. The Cavity Cont. 5. Body of the pubic bone. 6. Symphysis pubis . 7. Superior pubic ramus 8. Inferior pubic ramus 42

43. The Pelvic Outlet: The outlet is described in anatomical and obstetrical. Anatomical outlet : is made up of the tip of the coccyx, sacrotuberous ligaments , ischial tuberosities and the pubic arch 43

44. The Pelvic Outlet Cont. The Obstetric Outlet : The obstetrical outlet is of greater practical significance because that is the space available through which the fetus must pass during birth. It is diamond or kite in shape. It is bounded by: The lower border of the symphysis pubis. The ischial spines. MS ALICE OSEI 44

45. The Pelvic Outlet Cont. c. The sacrospinous ligament. The lower border of the sacrum. 45

46. The Pelvic outlet 46

47. The Pelvic Measurements They are important to the midwife because: if they are reduced or shortened, the baby either can not pass through the pelvis to be born. or the baby may pass through it with difficulty, thus causing injury to the mother and baby . 47

48. Measurement of the Pelvic Brim The Anterior Posterior Diameter/True Conjugate: The anterior posterior or true conjugate is taken from the promontory of the sacrum to the inner upper border of the symphysis pubis. It measures 11 cm. 48

49. Pelvic inlet/ brim measurement H 49

50. Diameter of the pelvic brim b . The Transverse Diameter: This is taken between the two points further most apart the iliopectineal lines. It measures 13cm. c. The Oblique Diameter: This is the distance between the sacroiliac joint and the opposite iliopectineal eminence. It measures 12cm. MS ALICE OSEI 50

51. Measurement of the pelvic brim cont. d . The Diagonal Conjugate: This is also measured anteroposteriorly from the lower boarder of the symphysis to the sacral promontory. It measures 12 -13cm and may be estimated per vaginum as part of the pelvic assessment. e. The Sacrocotyloid Diameter: It measures 9.5 cm. It measures from the sacral promontory to the illoipectineal eminence on each side. 2/5/2023 51

52. Diameter of the Pelvic Cavity a . The Anteroposterior Diameter: Measures 12cm. It is taken from the inner border of the symphysis pubis to curve /hollow of sacrum b. The Transverse Diameter: It measures 12cm. It is taken between the 2 points furthest apart on the lateral walls of the pelvis. 52

53. Diameter of the pelvic cavity cont. c . The Oblique Diameter: Measures 12 cm. They are measured from the right inner surface of the ischium to the left inner surface of the ischium . 2/5/2023 53

54. Measurement of the pelvic outlet The Anteroposterior Diameter: This is measured between the lower border of the symphysis pubis to the Sacrococcygeal joint. It measures 13cm. b) The Oblique Diameter: It measured between the obturator foramen and the spinous ligament, though there are no fixed points. It measures 12cm 54

55. Measurement of the pelvic outlet c) The Transverse Diameter: This is estimated between the ischial spines and measures 11 cm. It is the narrowest diameter in the pelvis. 55

56. The Pelvic Cavity Measurements. 2/5/2023 BERNICE OFOSU NTIAMAOH 56

57. The Pelvic Planes. These are imaginary flat surface at various levels of the pelvic canal. The ones commonly described are the brim, cavity and outlet. Plane of the brim: The plane marks the boundary between the false and true pelvis . 57

58. The Pelvic Planes cont. It is at an angle of 60ﹾc when standing. It is measured from the promontory of the sacrum to the upper bother of the symphysis pubis. 2/5/2023 58

59. The Pelvic Planes Plane of the cavity: This is the greatest pelvic dimension. That is the most roomy part of the pelvic. It is at an angle of 30 ﹾ c. It is from the upper border of the 3 rd sacral vertebrae and the midpoint of the symphysis pubis. 2/5/2023 MS ALICE OSEI 59

60. The Pelvic Planes cont. Planes of the outlet: This is the least pelvic dimensions. It is an angle of 15 ﹾ c. It extends from the lower border of the sacrum to the lower border of the symphysis pubis. 60

61. The Pelvic Planes 61

62. Axis of the pelvic canal. This describes the direction in which the fetus moves in order to pass through the pelvis canal. The fetus passes through the pelvic brim and the cavity in a downward and backward manner but at the level of the ischial spine, it turns sharply forwards. This corresponds with an imaginary line drawn at right angles to each of the pelvic planes. This imaginary line is also known as the Curve of Carus or the birth canal. MS ALICE OSEI 62

63. The Pelvic Inclination When a woman is in an upright position the pelvic is on an incline and the brim makes an angle of 60ﹾ with the floor. The cavity is 30 ﹾ and the outlet also makes an angle of 15 ﹾ . The anterior superior iliac spines lies above the symphysis pubis in the same vertical plane. The above angles are the same when the woman is in the recumbent position. MS ALICE OSEI 63

64. The pelvic inclination Cont. This must be kept in mind in abdominal examination The above angles are the same when the woman is in the recumbent position. This must be kept in the mind in abdominal examination. 64

65. PELVIC ASSESSMENT The function of pelvic assessment is to estimate whether the fetus will successfully pass through the pelvis during labour and delivery. The aim of the examination is to assess the pelvic size and outlet. Although this can be undertaken at any time before or during pregnancy, the relationship of the pelvis to the fetal skull can only be assessed from 37 weeks’ gestation (antenatally or during labour ) 65

66. Pelvic assessment cont. The following are done during pelvic assessment. 1. History Medical: A good medical history is taken to exclude conditions like osteomyelitis and rickety which might have effect on the pelvis. Surgical : A surgical history is also taken to exclude accident or injuries to the spine, pelvis or leg. Congenital dislocation of the hip may affect the shape of the pelvis. 66

67. Pelvic Assessment cont. Obstetric : A comprehensive history of previous pregnancies, delivery and puerperium should be taken. Type of deliveries, cause of caesarean section, still birth, forceps delivery must be stated. A spontaneous delivery of a baby weighing at least 3kg is suggestive of adequate pelvis. 67

68. 2 . General Examination Weight Height: Should not be less than 150cm and also shoe size should not be less than 4. The above observation give impression of clients proportions. E.g. a very tall woman with tiny feet is not well proportioned, neither is a short, stout woman especially with broad shoulder. 3. Abdominal Examination: At 36 – 37 weeks the abdomen is palpated to see if the fetal head is engaged or can be made to engage, that is the widest diameter can be pushed through the pelvic brim. MS ALICE OSEI 68

69. 4 . Vaginal examination In areas where modern techniques are not available, the doctor usually performs vaginal examination on every new patient attending antenatal clinic. (unless there is history of abortion) The doctor does this to confirm pregnancy and also to exclude abnormalities. Another examination is done from 36 th to 37 th week of pregnancy, to be sure the fetal head will pass through the pelvis and also assess the pelvic brim, cavity and outlet. 69

70. Vaginal examination cont . Assessment of the brim: This is made by estimating the diagonal conjugate. The two index fingers are placed in the vagina and an attempt is made to reach the promontory of the sacrum. The thumb is placed externally over the symphysis. If the sacral promontory is felt then the diagonal conjugate is reduced and the pelvis is said to be inadequate. 70

71. Vaginal Examination cont. Assessment of the cavity and the anterior posterior surface of the sacrum: It is palpated from above downwards, nothing if the sacrum is straight or concave. If the sacro spinous ligament is palpated it should be of a length that will accommodate 2-3 finger-breadths, across the greater sciatic notch. 71

72. Vaginal examination cont. Assessment of the outlet: The lateral borders of the outlet are assessed by the fingers feeling for the ischial spines which should be well rounded. The pubic arch should be well rounded to accommodate two fingers. A narrow sub-pubic angle is diagnosed if this is not possible. 72

73. 6. X’ Ray Pelvimetry This is the most accurate method of estimating the relationship between the maternal pelvis and the fetal head. Client is asked to empty her bladder before the examination is carried out. A standing lateral picture is taken so that the radiologist can measure the anteroposterior diameters of the brim, cavity and outlet. 73

74. X’ Ray Pelvimetry cont. The measurements obtained are then compared with the size of the fetal skull after which the obstetrician decides whether a vaginal delivery should be attempted or not. 74

75. Types of Pelvis The pelvis have been classically described as falling into 4 categories according to the shape of the brim. None of the four types are pathological unless any of the diameters are reduced substantially. It is impossible to classify a woman's pelvis in life unless she encounters difficulties in childbirth. It is possible to tell the sex and sometimes the race of a person by the shape of the pelvis. MS ALICE OSEI 75

76. Types of pelvis The normal classification used is that of Caldwell and Molley . Gynaecoid pelvis Android pelvis Platypelloid pelvis Anthropoid pelvis 76

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78. The Gynaecoid pelvis This is the normal female pelvis and it is ideal for child bearing. It goes with the typical feminine figure with hips broader than the shoulders and the limbs length proportionate to the rest of the body. Characteristics: 1. It is  found in approximately 50% of all women and considered a true female pelvis 2. Brim is almost round. MS ALICE OSEI 78

79. The Gynaecoid pelvis cont. 3 . The transverse diameter of the outlet is at least 10cm. Cavity: 4. The true pelvis is shallow 5. Sacrum is well curved 7. The side walls are straight. 8. The sciatic notch is wide. Outlet: 9. The sub pubic angle is 90 ﹾ wide. 10. Ischial spines are not prominent. 79

80. The Gynaecoid pelvis cont. Effect on labour: The gynaecoid pelvis is well rounded anteriorly, this makes the fetus present with the most rounded part of his head (occiput). 80

81. The Android (male type of pelvis) This type of pelvis resembles the male type of pelvis. The bones are heavier than that of the female pelvis. It usually goes with tall women with broad shoulders and male distribution of hair. Characteristics: 1. Incidence 20% of females. 2. Brim is triangular or heart in shape with a narrow fore pelvis and broad at the back. 81

82. The Android (male type of pelvis) cont . 2. The transverse diameter does not cross the center of the anterior posterior diameter but it is much nearer the sacrum. Cavity : 3. The true pelvis is deep. 4. The hollow of the sacrum is almost straight. 5. The side walls converge which cause funneling and contraction towards the outlet. 82

83. The Android (male type of pelvis) cont. 5 .The greater sciatic notch is narrow. Outlet: 6. The sub-pubic angle is narrow, that is less than 90%. 7. The ischial spines are prominent which sometimes prevent complete internal rotation of the head and the anteroposterior diameter of the outlet is also reduced 83

84. The Android (male type of pelvis) cont. Effect on labour: Occipito -posterior position is favored because of the shape of the brim as there is more room at the back. Usually in the posterior positions labour tends to be prolonged but delivery is normal . 84

85. The Android Pelvis cont. Funneling of the cavity hinders internal rotation and therefore persistence occipito posterior position or deep transverse arrest may occur. Prominent ischial spines will prevent descent and the narrow pubic arch will not allow delivery of the occiput. 85

86. The Anthropoid pelvis This type of pelvis resembles the pelvis of the great ape. It is usually found in tall and well built women with narrow shoulders. Characteristics: Incidence is 25% of females. Brim is oval The anteroposterior diameter is longer than the transverse diameter. 86

87. The Anthropoid pelvis cont. Cavity : 4. The sacrum is long and deeply concave. 5. Side walls diverge. 6. The greater sciatic notch is wide. Outlet : 7.The sub pubic angle is wide . 8. The ischial spines are not prominent . 87

88. The Anthropoid pelvis cont. Effect on Labour : The head engages in direct occipito – anterior or occipito posterior position. No relation is necessary, so the head descends through the cavity and outlet without difficulty. Thus the position adopted for engagement may persist to delivery . 88

89. The Platypelloid pelvis This corresponds with the simple flat pelvis. Characteristics: Incidence is 5% of females. Brim is kidney shaped. Anterior posterior diameter is shortened but the transverse diameter is lengthened. Cavity: 5. The sacrum is flat and the cavity is shallow. 6. The side walls diverge. 89

90. The Platypelloid pelvis cont. Outlet. 7. Sub pubic angle is greater than 90˚ sciatic notch is wide 8.Ischial spines are blunt. 2/5/2023 90

91. The Platypelloid pelvis Effects on labour : Engagement of the head in the Antero transverse diameter of the inlet is favored. Rotation of the head is likely to occur. The biparietal diameter of the fetal skull is held in the sacrocotycoid diameter of the pelvic brim. Good uterine contractions will cause the head to extend as it descends. This results in face presentation . 91

92. The Platypelloid Pelvis Cont. Engagement of the fetal skull may necessitate lateral tilting of the head known as asynclitism , in order to allow the biparietal diameter to pass the narrowest antero posterior diameter of the brim 92

93. Other pelvic variations. Justo- Minor pelvis: This is a small gynaecoid pelvis. It is usually found in less than 1.5m tall petite women. All diameters of the pelvis are reduced. The type of labour and delivery will depend on the size of the baby. 93

94. 2/5/2023 BERNICE OFOSU NTIAMAOH 94

95. 2. High assimilation pelvis This is when the 5 th lumber vertebra is fused to the sacrum and the angle of inclination of the pelvic brim is increased. During labour , it is difficult for the head to engage when engagement is achieved labour progress normally. 3. Deformed pelvis: This may results from a developmental anomaly, dietary deficiency injury or disease. 2/5/2023 MS ALICE OSEI 95

96. Deformed pelvis cont. a . Naegele’s: This may be due to congenital abnormality. In naegele’s pelvis one sacral ala or wing is missing and the sacrum is fused to the ilium causing a grossly asymmetric brim. Delivery by caesarian section is always indicated. b. Robert Pelvis: This may also be due to congenital abnormality. In this, both alae are missing 2/5/2023 96

97. Deformed pelvis cont. It is contracted in all diameters. In both instances abnormal brim prevents engagement of the fetal head. Delivery is by caesarian section. 2/5/2023 97

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99. 4. Dietary Deficiency C. Rachitic Pelvis : Rickets in early childhood can lead to gross deformity of the pelvic brim. The weight of the upper body is on the pelvis. The sacral promontory is pushed downwards and forward and the ilium and ischium are drawn outwards. This results in flat pelvis which is similar to platypelloid pelvis . 2/5/2023 99

100. Rachitic Pelvis 2/5/2023 100

101. Dietary Deficiency cont. Osteomalacic Pelvis: This is caused by acquitted deficiency of calcium and occurs in adults. All bone of the skeleton are soften. The pelvic canal is squashed together until the brim becomes a Y shaped slit. Caesarean section is performed since vaginal delivery delivery is impossible. 2/5/2023 101

102. Osteomalacic Pelvis 2/5/2023 102

103. Injury and diseases of the pelvis Trauma: A pelvis which has been fractured will develop callus formation or may fail to unit properly. This may lead to reduced measurement and some degree of contraction. E.g of disease and injuries are fractures and poliomyelitis. Contracted pelvis: This is where one or more of the essential diameter is reduced by one centimeters or more. 2/5/2023 103

104. Contracted pelvis 2/5/2023 BERNICE OFOSU NTIAMAOH 104

105. The pelvic Joints in pregnancy and labour . There is an increase in mobility of the pelvic joints towards the end of pregnancy. This increase in mobility is caused by the hormone relaxin which acts on collagen which softens and cause relaxation of the pelvic ligaments. 1. The symphysis pubis: The symphysis pubis is widened by at least a further 3mm which brings about an increase in all pelvic diameter of the brim, cavity and outlet. 2/5/2023 105

106. The pelvic Joints in pregnancy and labour cont. The fibrocartilaginous symphysis disc also softens In some women the symphysial widening is so great that there is movement in the pubic bodies when the person is moving to a standing position or when walking. This condition usually causes pain as early as 26 weeks of pregnancy and a firm corset needs to be worn for support . 106

107. The pelvic Joints in pregnancy and labour cont. Sacro iliac joint: The increasing weight of pregnancy coupled with the increased mobility of the pelvic joints makes the pregnant woman adopts the attitude of lordosis. Usually, towards the end of the pregnancy, many women complain of back pain and discomfort. 107

108. The pelvic Joints in pregnancy and labour cont . Sacrococcygeal joint: The hormone causes the coccyx to tilt back to facilitate passage of the fetal head during delivery . 108

109. Functions of the bony pelvis The primary function is to allow movement of the body especially walking and running. It helps the person to sit and kneel. The pelvis is adapted for childbirth. It also transmit the weight of the trunk to the legs acting as a bridge between the femurs. 109

110. Functions of the bony pelvis cont. The pelvis takes the weight of the sitting body onto the ischial tuberosities. It also protects the pelvic organs. 110

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