The unexpected results from an investigation into hereditary congenital anorectal malformations of pig embryos have demonstrated the weakness of earlier interpretations and constructions and underlined the need for a new inquiry into the normal development of the area in human embryos. It demonstrated that although data from malformations may offer extra information about the normal development of the area, great care has to be taken in using that information for the reconstruction of its normal development which should be firmly based on the observation of the evolving microscopic anatomy of the region in the first place.
Author(s): S.C.J. van der Putte
Edition: 1
Year: 2004
Language: English
Pages: 135
Contents......Page 7
1 Introduction......Page 10
2 Materials and Methods......Page 11
3.1 Introduction......Page 12
3.2.1 Precloacal Perineum (e.3–5 mm Total Length, 24–28 Days Fertilization Age, Carnegie Stage XI–XIII)......Page 13
3.2.2 Cloacal Perineum (e.5–15 mm CRL, 26–45 Days Fertilization Age, Carnegie Stages XIV–XVIII)......Page 14
3.2.3 Postcloacal Sexually Indifferent Perineum (e.15–32 mm CRL, 44–56 Days, Carnegie Stage XVIII–XXIII)......Page 26
3.3 Discussion......Page 40
3.3.2 Cloaca and Allantois: Partition of Mesonephric and Ureteric Systems......Page 41
3.3.3 Division of the Cloaca......Page 43
3.3.4 Urogenital Sinus......Page 45
3.3.5 Anal Canal......Page 49
3.3.6 Perineal Striated Musculature......Page 50
3.3.7 Vascular System......Page 51
4.1 Introduction......Page 52
4.2 Observations......Page 53
4.2.1 Vagina......Page 55
4.2.2 Transformation of the Urogenital Sinus into the Urethra and Vestibulum......Page 59
4.2.3 Urethra......Page 61
4.2.4 Vestibulum......Page 64
4.2.5 Erectile Structures......Page 66
4.2.6 Fascial Tissues......Page 68
4.2.8 Anal Canal......Page 73
4.2.10 External Perineum......Page 76
4.3 Discussion......Page 77
4.3.1 Vagina......Page 78
4.3.2 Transformation of the Urogenital Sinus into the Urethra and Vestibulum......Page 82
4.3.3 Urethra......Page 83
4.3.4 Vestibulum......Page 84
4.3.5 Labia Majora......Page 87
4.3.6 Anal Canal......Page 88
4.3.7 External Perineum......Page 89
5.1 Introduction......Page 90
5.2 Observations......Page 91
5.2.1 Urethra......Page 92
5.2.2 Erectile Structures......Page 103
5.2.3 Fascial Tissues......Page 106
5.2.4 Perineal Raphe, Septum, Body, and Fasciae......Page 108
5.2.5 Scrotum......Page 111
5.2.6 Penis, Prepuce, Preputial Sac and Frenulum......Page 113
5.2.8 Perineal Striated Musculature......Page 116
5.2.9 External Perineum......Page 117
5.3.1 Urethra......Page 118
5.3.2 Erectile Structures......Page 122
5.3.3 Perineal Raphe, Septum, Body, and Fasciae......Page 123
5.3.4 Penis, Prepuce, Preputial Sac, and Frenulum......Page 125
6 Summary......Page 127
References......Page 135
G......Page 141
S......Page 142
V......Page 143
