31. The female pelvis and pelvic floor for KEATS
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Female pelvis and pelvic floor
Course: Biosciences for Midwifery Practice 4KNIW001
Lecturer: Rebecca Daley, Florence Nightingale Faculty of Nursing, Midwifery & Palliative Care
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Learning Outcomes
Identify bones and joints of the pelvis.
Define pelvic brim, cavity, and outlet; explain their significance in labour and birth.
Identify pelvic floor muscles.
Understand physiological changes during childbearing.
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Preparation for Session
Complete learning activities prior to the teaching day:
Watch HELM videos:
The Maternal Pelvis (9 min)
Pelvic Joints (3 min)
Pelvic Ligaments (4 min)
Landmarks of Pelvic Brim, Cavity, and Outlet (6 min)
Diameters of the Pelvis (3 min)
Complete eLFH module "Introduction to the Pelvic Floor during Pregnancy."
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Introduction
Fetus navigates the maternal pelvis during vaginal birth.
Knowledge of female pelvis and pelvic floor is crucial for understanding labour physiology.
Landmarks help to identify fetal position and descent.
Pelvic floor muscles assist in fetal rotation during descent through birth canal.
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Female Pelvis
Strong bony structure articulating with lumbar vertebrae and femoral heads.
Provides movement and protects pelvic organs.
Muscles support bladder, vagina, uterus, and rectum.
Four bones: two pelvic bones, one sacrum, one coccyx.
Four joints: two sacroiliac joints, symphysis pubis, and sacrococcygeal joint.
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Pelvic Girdle
Pelvic bones unite at the symphysis pubis and sacroiliac joints.
Acetabulum forms part of the hip joint with femur head.
Ilium is the superior part; ischium forms the inferior part.
Ischial tuberosities felt when sitting; ischial spines define fetal descent.
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True & False Pelvis
Pelvis divided into false pelvis above iliopectineal line and true pelvis below.
True pelvis important for vaginal birth; includes brim, cavity, and outlet.
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Pelvic Brim
Oval shape; significant landmarks include sacral promontory and symphysis pubis.
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Pelvic Cavity
Extends from brim to outlet; has a circular shape with a slight inclination.
Fetus follows the curve of Carus during vaginal birth.
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Pelvic Outlet
Ovoid/diamond shaped; landmarks include symphysis pubis and ischial spines.
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Pelvic Diameters
Four principal diameters:
Anteroposterior diameter
Transverse diameter
Two oblique diameters.
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Pelvic Conjugates
Anatomical conjugate (~12cm) and obstetric conjugate (~11cm).
Diagonal conjugate (~13cm) can be estimated vaginally.
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Pelvic Floor
Strong structure to support pelvic contents during upright posture; involved in various functions.
Consists of two layers of muscles, ligaments, and connective tissue.
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Deep Muscle Layer (Levator Ani)
Muscles support pelvic organs and resist intraabdominal pressure; supplied by pudendal arteries and sacral nerves.
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Superficial Muscle Layer
Includes ischiocavernosus, bulbocavernosus, and transverse perineal muscles, as well as sphincters.
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Perineal Body
Vital area where many muscles join; involved in vaginal birth and defecation; commonly torn during childbirth.
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Perineal Trauma
Types of tears during childbirth:
1st degree: skin only.
2nd degree: perineal muscles.
3rd degree: involves anal sphincter.
4th degree: involves sphincter complex and anal epithelium.
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Physiological Changes During Pregnancy
Progesterone relaxes pelvic ligaments; may increase dimensions but cause pain.
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Postnatal Changes
Ligaments tighten; pelvic muscles need recovery post-birth to support pelvic function and prevent long-term issues.
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Pelvic Girdle Pain (PGP)
Pain in pelvis that affects mobility; formerly called symphysis pubis dysfunction; affects quality of life.
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Incontinence
Up to 60% of women experience urinary incontinence during pregnancy; pelvic floor exercises can reduce this risk.
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Pelvic Floor Exercises
Importance of educating women about pelvic exercises; referral pathways for those at risk of pelvic floor dysfunction.
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Consolidating Your Learning
Suggested core learning activities post-teaching include reading specified chapters and viewing recommended videos.
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References
A list of key references related to midwifery, anatomy, physiology, and pelvic health.
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Contact Information
Rebecca Daley, Lecturer in Midwifery Education, King's College London.