ANATOMY OF THE BONY PELVIS: A STUDY IN ANDROID STRUCTURE

Lateefa Al Dakhyel FRCSC, FACOG

Assistant professor & consultantObstetric & gynecology departmentCollage of medicineKing Saud University

There are some differences in the structure of female pelvis in human.They have significant effects on labor and difficulty in child-birth.

We shall discuss Caldwell-Moloy classification of female pelvis and discuss the causes and effects of the “Android” pelvic stucture.

Pelvic shapes►Caldwell-Moloy classification

-A line drawn through the greatest diameter of the inlet divides it to ant. & post.

•Gynaecoid pelvis:

1.It is the commonest type (60%)2.Inlet is slightly oval or round (TD~APD)3.Sacrum is wide with average concavity and inclination. 4.ischial spines not prominent (transverse diameter is = >10cm) 5.Sacro-sciatic notch is wide.6. wide pubic arch

•Anthropoid pelvis:

1.It makes 30% of white & ~ 50% of nonwhite women.2.All anteroposterior diameters are more than transverse diameters

(Oval anteroposteriorly)3.Ischial spines mostly prominent.4.Sacrum is long and narrow. 5.Sacro-sciatic notch is wide.

6.Subpubic angle is narrow.

• Android pelvis :

1.It is~ 12% of white & ~8% 0f nonwhite women. 2.Inlet is triangular or heart-shaped with anterior narrow

apex. 3.Side walls are converging (funnel pelvis) with projecting

ischial spines. 4.Sacro-sciatic notch is narrow.

5.Subpubic angle is narrow <90o. 6.The extreme android pelvis have poor prognosis for

vaginal delivery.

•Platypelloid pelvis :

1.It is a flat female type, it is rarest ~3% of women only.2.All anteroposterior diameters are short. 3.All transverse diameters are long (oval transverse)4.Sacro-sciatic notch is narrow.

5.Subpubic angle is wide. 6.The sacrum usually is well curved and rotated backward.

Clinical estimation of pelvic size

Among these pelvic structure: Gynaecoid structure is most suitable for

vaginal labor Anthropoid and Platypelloid structures have

lower risks of complexity during labor. Android structure may cause difficulties

during child birth and often subjected to prolonged painful labor.

The reason behind the complexity of labor is Android pelvis has narrower opening at the

bottom to let the baby slide through.

Detecting Android PelvisYou can easily detect a patient’s Android pelvis from x-raying her waist. You should find a heart-shape or triangular pelvic cavity instead of a circle or oval and narrower bottom towards birth canal.

X-raying pelvic girdle is somewhat risky and advised to be avoid unless necessary. You can diagnose android pelvis by examining the patient’s features.

Detecting Android Pelvis (Cont.)

According to Caldwell-Moloy, android pelvis is a result of lack of secondary sexual development. Subject should be fully sexually functional and fertile but she will show some sign of less feminine attributes.

Detecting android pelvis is necessary for taking precautions if subject is willing to give birth vaginally

Detecting Android Pelvis (Cont.)Lower Sex Drive

Subject may or may not have lower attraction for sexual activity

Less Feminine BodySubject should have smaller breasts, stronger body structure and fatty stomach

Harder Vaginal WallSubject should have harder and smaller vaginal interior like teenage girls

Causes of Android Pelvis•There is no definite cause of android pelvic structure.

Some women tend to have this pelvic structure. It is more common in Asian women

•Android pelvis is a result of lack of changes during puberty. A woman with android pelvis shows the

physical attributes of teenage girl or premature woman

•It can be a result of premature puberty. Girls who experience menstrual cycles earlier age can have

android pelvis. It is because their puberty starts before their body is totally ready for the abrupt changes.

Therefore, their physical changes may remain limited to the essential changes needed for reproductive functions

Android pelvis: Narrow Pelvic Canal

•The structure of upper pelvis is normal or circular, therefore no problem during pregnancy. Can bear fully

healthy baby

•The opening of the pelvic canal is narrow. May require extra effort to give birth causing painful prolonged labor

•Once the head of the baby is out of pelvis and reaches vagina, the rest is normal. But she has slightly higher

risk to get vaginal walls damaged as her walls have less elasticity than most other women.

Android Pelvis: Lower Sex Drive•The lack of secondary sexual development which

causes Android pelvis, is also responsible for reduced sex drive in women

•Subject shows no problem in sexual activities or enjoying sex, but she may feel less attracted to sex in

normal cases

•Difficult to excite for sex, but once excited she enjoys the intercourse normally

Android Pelvis: Harder Interior of Vaginal Wall

•During puberty normally vagina goes through a lot of changes and becomes very soft. According to Caldwell-

Moloy android subject’s vagina does not go through many of the normal changes and remain harder

•There are both pros and cons of hard vagina. Hard vagina does not mature and remains like teenage girl’s

for most of the life. Subject remains sexually active up to older ages than normal as her vagina remains young

•Men like teenage-girl-like vagina because harder vaginal wall squeezes penis during sex which triggers more

nerve endings. Therefore men feel more pleasure and stimulation in their penis during coitus

Android Pelvis: Harder Interior of Vaginal Wall (Cont.)

•Although men receive more pleasure, they struggle to satisfy women with hard vagina. With more stimulation from rigid vaginal walls men reach orgasm very quickly and often cannot have coitus for long enough to satisfy

female partner. This may frustrate women and upset men, as they cannot fulfill their instinct of dominating

their women during sex by satisfying them with prolonged coitus

•Harder vagina has higher risk of tissue damage during child birth

Android Pelvis: Less Feminine Body Structure

•According to Caldwell-Moloy, subject having android •pelvis tends to have less feminine body structure

•Subject with high probability does have smaller breasts, stronger body structure, fatty stomach, higher RBC and

deeper breath

•Subject may show athletic skills and symptoms of high blood pressure in later period of life

•Smaller breast is caused by lack of fatty tissue in chest region, there is enough milk gland to produce enough

milk for baby

Android Pelvis: Challenging Sex-life•Subject shows lower libido. Her partner should be

sensible. She will enjoy sex if initiated with care

•Intercourse may be imbalanced, as her teenage-girl-like vagina provides supreme pleasure to her man, but due

to this extra sensation her man is more likely to finish earlier than she needs to be satisfied

•Her partner should learn what makes her happy and how to please her during coitus and apply those skills

carefully. He must resist his male instinct of rough coitus to establish domination. In stead he should keep calm

and make love very slowly to fulfill her desire. This may need some will power but can be achieved by practice

Android Pelvis: In Popular Culture•Most of the sculptures of ancient Greece have body

structures of that of android pelvic women. Greeks did not care about the satisfying the women and as these

women offered more pleasing coitus for man physically, they were selected to represent Greek goddesses

•Girls with smaller breasts were called lotus women in ancient India and were considered to give birth male

children. In India, it was thought that labor pain is harder for male children. As android pelvic women had often

difficulties during labor, they were supposed to mother desirable male children. For this reason they were

ranked high in ancient Indian culture

Android Pelvis: In Popular Cultures (Contd.)

•The art and sculptures of ancient Romans feature women with more feminine structure and Android pelvic

women were categorized as the worst kind. Because Roman culture shaped the males as warriors and

according to their documents they liked to dominate their ladies completely. The process of coitus included

torture and punishments with very rough venereal acts. Women with rigid vaginas were hard to dominate as

intercourse with them does not last longer. Therefore, they were not liked by Romans

Android Pelvis: Further Study

You can read about all four pelvis type and their causes, effects and consequences in detail in the classification of

female bony pelvis by Caldwell-Moloy

You shall find necessary contents to understand the structure of bony pelvis, pelvic muscles and ligaments in

detail in Grey’s Anatomy

END OF PRESENTATIONThank You