L1: Female Pelvis Flashcards
Bony Pelvis is formed of ……
Position of False Pelvis
Boundaries of False Pelvis
Importance of False Pelvis
Site of True Pelvis
Parts of True Pelvis
- Pelvic inlet.
- Pelvic cavity.
- Pelvic outlet.
What are another names of Pelvis Inlet?
Pelvic Brim or Superior Striat
Plane of Pelvic Inlet
Imaginary line joining the following points:
Upper border of symphysis pubis.
Superior pubic ramus.
Iliopectineal eminence.
Iliopectineal line.
Sacroiliac joint.
Ala of sacrum.
Pubic tubercle.
Pubic crest.
Promontory of sacrum.
Other points on opposite side.
Axis of Pelvic Inlet
- Represented by imaginary line perpendicular to center of plane of pelvic inlet.
- If this line extends upwards, it will pass to umbilicus & if it extends downwards, it will pass to tip of coccyx.
Pelvic Inclination
- Def
- Plane of pelvic inlet makes angle of 40-60° (average 55) with horizontal line in standing position.
Pelvic Inclination
- Measurment
- Measured in X-ray by measuring angle () pelvic brim & anterior surface of Ls (normally = 135°).
Pelvic Inclination
- Importance
- The higher the pelvic inclination, the more favorable vaginal delivery.
Pelvic Inclination
- Diameters
All (except diagonal conjugate) are measured only radiologically.
Pelvic Brim Index
Diameters of Pelvic Inlet
Diameters of Pelvic Inlet
- AP
Diameters of Pelvic Inlet
Diameters of Pelvic Inlet
- Transverse
Diameters of Pelvic Inlet
- Other Diameters
Length of True Conjugate (Anatomical AP - Conjugata Vera)
11cm
Extent of True Conjugate (Anatomical AP - Conjugata Vera)
- Tip of sacral promontory
to
- Posterior part of upper border of symphysis pubis
Importance of True Conjugate (Anatomical AP - Conjugata Vera)
Divided by anatomical transverse diameter into:
- Anterior sagittal diameter of inlet (7 cm)
- Posterior sagittal diameter of inlet (4 cm)
Length of Obstetric Conjuate Diameter
10.5 cm
Extent of Obstetric Conjuate Diameter
- Tip of sacral promontory
to
- Most bulging point on posterior surface of symphysis pubis
Importance of Obstetric Conjuate Diameter
- Most important A-P diameter it is the shortest one through which fetus must pass)
Length of Diagonal Conjugate Diameter
12.5 cm
Extent of Diagonal Conjugate Diameter
- Tip of sacral promontory
to
- Lower border of symphysis pubis
Importance of Diagonal Conjugate Diameter
- Can be measured clinically & approximate length of true conjugate is calculated by subtracting 1.5 cm.
Length of Anatomical Transverse Diameter
13 cm
Extent of Anatomical Transverse Diameter
() 2 farthest points on iliopectineal line
Importance of Anatomical Transverse Diameter
Divides true conjugate into:
- Anterior sagittal diameter of inlet (7 cm)
- Posterior sagittal diameter of inlet (4 cm)
Length of Obstetric transverse Diameter
12 cm
Extent of Obstetric transverse Diameter
Bisects true conjugate diameter
Importance of Obstetric transverse Diameter
The available transverse diameter for head (the shortest)
Length of Oblique Diameters
12 cm
Extent of Oblique Diameters
- Sacroiliac joint on one side
to
- Iliopectineal eminence on the other side.
Importance of Oblique Diameters
Named (Rt or Lt) according to joint & Lt diameter is slightly shorter than Rt due to:
- More frequent use of Rt leg,
- Encroachment of sigmoid colon on Lt diameter.
Length of Sacrocotyloid Diameters
9-9.5 cm
Extent of Sacrocotyloid Diameters
- Center of sacral promontory.
to
- Iliopectineal eminence
Importance of Sacrocotyloid Diameters
Named (Rt or Lt) according to eminence
Boundaries of Pelvic Cavity
Boundaries of Plane of Greatest Pelvic Dimensions
Boundaries of Plane of Obstetric Midpelvis
Boundaries of Plane of Least Pelvic Dimensions
Plane of Greatest Pelvic Dimensions is the ……. part of the pelvis and is almost ………
Roomiest - Circular
Plane of Greatest Pelvic Dimensions
- Diameters
- AP
- Transverse
Plane of Greatest Pelvic Dimensions
- AP Diameter
Plane of Greatest Pelvic Dimensions
- Transverse Diameter
Plane of Greatest Pelvic Dimensions
- Importance
- Internal rotation of the head occurs when the biparietal diameter occupies this wide plane of pelvis
- Disimpaction of the head to this plane is done before manual rotation in cases of occipito posterior position
Plane of Obstetric Midpelvis
- Diameters
Plane of Obstetric Midpelvis
- AP Diameter
Plane of Obstetric Midpelvis
- Inter-spinous Diameter
Plane of Obstetric Midpelvis
- Anterior Sagittal Diameter
Plane of Obstetric Midpelvis
- Posterior Sagittal Diameter
Plane of Obstetric Midpelvis
- Importance
Plane of Least Pelvic Dimensions
- Diameters
- AP
- Transverse
Plane of Least Pelvic Dimensions
- AP
Plane of Least Pelvic Dimensions
- Transverse Diameter
Plane of Least Pelvic Dimensions
- Importance
- At this plane, the obstetrics pelvic axis turns forwards.
- The vertex is considered engaged when the lowermost bony part reaches this plane (ischial spines).
What is another name of Pelvic Outlet?
Inferior Striat
Types of Pelvic Outlet
Anatomical & Obstetric
Def of Anatomical Outlet
- Lozenge shaped formed of 2 triangles at 2 different planes with common base formed by bituberous diameter.
Triangles & Boundaries of Anatomical Outlet
Anatomical Outlet
- Anterior Sagittal Triangle
Anatomical Outlet
- Posterior Sagittal Triangle
Diameters of Anatomical Outlet
- AP
- Transverse (bituberous)
- Anterior Sagittal
- Posterior Sagittal
Diameters of Anatomical Outlet
- AP
Diameters of Anatomical Outlet
- Transverse (Bituberous)
Diameters of Anatomical Outlet
- Anterior Sagittal
Diameters of Anatomical Outlet
- Posterior Sagittal
Thorn’s (Klein’s) Dictum
- To allow average sized fetal head to pass through pelvic outlet → bituberous diameter + posterior sagittal diameter of pelvic outlet must be > 15 cm provided that bituberous diameter is > 8 cm.
Def of Obstetric Outlet
Segment of pelvis bounded above by plane of least pelvic dimensions & below by anatomical outlet.
Boundaries of Obstetric Outlet
Diameters of Obstetric Outlet
- AP
- Transverse (Bispinous)
Diameters of Obstetric Outlet
- AP
Diameters of Obstetric Outlet
- Transverse (Bispinous)
Types of Pelvic Axis
- Anatomical (Curve of Carus)
- Obstetric
Anatomical Pelvic Axis
Obstetric Pelvic Axis
Diameters of Bony Pelvis (Summary)
- Pelvic Inlet
Diameters of Bony Pelvis (Summary)
- Plane of GPD
12 cm all round
Diameters of Bony Pelvis (Summary)
- Plane of MP
Diameters of Bony Pelvis (Summary)
- Plane of LPD
Diameters of Bony Pelvis (Summary)
- Anatomical Outlet
Classification of Female Pelvis
Classification of Female Pelvis is based on ……
Caldwell & Moloy have classified female pelvises based on radiological studies into four types
Gynecoid Pelvis
- Incidence
- Pelvic Inlet
- Sacrum
- Pelvic Cavity
- Sunpubic Angle
- Head Engagment
- Pelvic Reserve Capacity
- Clinical Importance
Android Pelvis
- Incidence
- Pelvic Inlet
- Sacrum
- Pelvic Cavity
- Sunpubic Angle
- Head Engagment
- Pelvic Reserve Capacity
- Clinical Importance
Anthropoid Pelvis
- Incidence
- Pelvic Inlet
- Sacrum
- Pelvic Cavity
- Sunpubic Angle
- Head Engagment
- Pelvic Reserve Capacity
- Clinical Importance
Platypelloid Pelvis
- Incidence
- Pelvic Inlet
- Sacrum
- Pelvic Cavity
- Sunpubic Angle
- Head Engagment
- Pelvic Reserve Capacity
- Clinical Importance
Compare between Gtnecoid, Android, Anthropoid, Platypelloid Pelvis in terms of:
- Incidence
- Pelvic Inlet
- Sacrum
- Pelvic Cavity
- Sunpubic Angle
- Head Engagment
- Pelvic Reserve Capacity
- Clinical Importance
Incidence of Gynecoid Pelvis
50 %
Pelvic Inlet in Gynecoid Pelvis
oval
Pelvic Inlet in Android Pelvis
- Triangular with narrow anterior segment & wide flat posterior segment
Head Engagment in Android Pelvis
In transverse diameter