notes on midwifery

1. ANATOMY OF THE FEMALE REPRODUCTIVE SYSTEM
Surface features of the anterior abdominal wall
 The outline of the anterior abdominal wall is approximately
hexagonal.
Superiorly
1. Xiphisternal junction (process) at the summit of the arch
2. Arched costal margin on both sides
Lateral boundary
1. Vertical mid-axillary line on either side extending between
the lateral part of the costal margin and the summit of the
iliac crest
Inferiorly
 On each side, the anterior abdominal wall is bounded in
continuity, from lateral to medial, by
1. The anterior half of the corresponding iliac crest,
2. The ipsilateral inguinal ligament and
3. The upper surface of the pubic bone and
4. The pubic symphysis

2. Layers of the anterior abdominal wall
1. Skin
 The skin of the anterior abdominal wall is capable of
undergoing enormous stretching.
 Undue stretching may result in the formation of whitish streaks
in the skin of the lower part of the anterior abdominal wall;
these are known as lineae albicantes.
2. Superficial fascia
 Below the level of the umbilicus, the superficial fascia of the
anterior abdominal wall is divided into
1. A superficial fatty layer (fascia of Camper)
2. A deep membranous layer (fascia of Scarpa)
 The various contents of the superficial fascia run between these
two layers.
 The membranous layer is continuous below with a similar
membranous layer of superficial fascia of the perineum known
as Colles’ fascia.
 In the median plane, the membranous layer is thickened to
form the suspensory ligament of the penis or of the clitoris
 The fascia contains:

3. 1. An extremely variable quantity of fat, which tends to
accumulate in the lower part of the abdomen after puberty;
2. Cutaneous nerves:
3. Cutaneous vessels; and
4. Superficial lymphatics.
3. Musculo-aponeurotic layer
 The anterior abdominal wall is made up mainly of muscles.
 On either side of the midline there are four large muscles.
These are
1. The external oblique,
2. The internal oblique,
3. The transversus abdominis and
4. The rectus abdominis
 Two small muscles, the cremaster and the pyramidalis are also
present.
 The external oblique, the internal oblique and the transversus
abdominis are large flat muscles placed in the anterolateral part
of the abdominal wall.
 Each of them ends in an extensive aponeurosis that reaches the
midline.
 Here the aponeuroses of the right and left sides decussate to
form a median band called the linea alba.
 The rectus abdominis runs vertically on either side of the linea
alba.

4.  It is enclosed in a sheath formed by the aponeuroses of the flat
muscles named above.
4. Fascia transversalis
 The Inner surface of the abdominal muscles is lined by fascia
which is separated from peritoneum by extraperitoneal
connective tissue.
 That part of the fascia which lines the inner surface of the
transversus abdominis muscle is called the fascia transversalis
5. A properitoneal adipose layer (containing a variable amount
of fat)
6. Parietal peritoneum
BONY PELVIS
Introduction:
 The pelvis is a basin-shaped ring of bones that marks the distal
margin of the trunk
 The 2 major pelvic divisions are the pelvis major (upper or false
pelvis) and the pelvis minor (lower or true pelvis).

5.  The pelvis major consists primarily of the space superior to the
iliopectineal line, including the 2 iliac fossae and the region
between them.
 The pelvis minor, located below the iliopectineal line, is
bounded anteriorly by the pubic bones, posteriorly by the
sacrum and coccyx, and laterally by the ischium and a small
segment of the ilium.
Outlets of the True Pelvis
 The true pelvis is said to have an upper "inlet" and a lower
"outlet."
 The pelvic inlet to the pelvis minor is bounded, beginning
posteriorly, by
1. The promontory of the sacrum;
2. The linea terminalis
3. The upper border or crest of the pubis, ending medially at
the symphysis.
 The conjugate or the anteroposterior diameter is drawn from
the center of the promontory to the symphysis pubica, with 2
conjugates recognized:
1. The true conjugate (obstetric conjugate), measured from the
promontory to the top of the symphysis, and
2. The diagonal conjugate (false conjugate), measured from the
promontory to the bottom of the symphysis

6.  The transverse diameter is measured through the greatest width
of the pelvic inlet.
 The oblique diameter runs from the sacroiliac joint of one side
to the iliopectineal eminence of the other
 Subtracting 1.5 cm from the diagonal conjugate gives a
satisfactory estimate of the true conjugate (conjugata vera), or
the true anterior diameter of the pelvic inlet.
 The pelvic outlet, which faces downward and slightly backward,
is very irregular.
 Beginning anteriorly, it is bounded by
1. The arcuate ligament of the pubis (in the midline),
2. The ischiopubic arch,
3. The ischial tuberosity,
4. The sacrotuberous ligament, and
5. The coccyx (in midline)
 Its anteroposterior diameter is drawn from the lower border of
the symphysis pubica to the tip of the coccyx.
 The transverse diameter passes between the medial surfaces of
the ischial tuberosities.
 The cavity of the true pelvis can be described as an obliquely
truncated, bent cylinder with its greatest height posteriorly,
because its anterior wall at the symphysis pubis measures about
5 cm and its posterior wall about 10 cm
 The ischial spines are of great obstetrical importance because
the distance between them usually represents the shortest
diameter of the pelvic cavity.

7. Planes and diameters of the pelvis
The pelvis is described as having four imaginary planes:
1. The plane of the pelvic inlet (superior strait).
2. The plane of the pelvic outlet (inferior strait).
3. The plane of the midpelvis (least pelvic dimensions).
4. The plane of greatest pelvic dimensions.
1. PELVIC INLET (BRIM)
 At the Brim, the least accepted diameters are:
i) Anteroposterior Diameter
 From upper inner border of pubic symphysis to sacral
promontory: 11 cm.
 The obstetric conjugate is the shortest distance between pubic
symphysis and sacral promontory taken from the inner mid-
point of the symphysis pubis.
 It is approximately 1.5cm ’ 2.0cm less than the diagonal
conjugate.
 The anteroposterior diameter of the pelvic inlet that has been
identified as the true conjugate does not represent the shortest
distance between the promontory of the sacrum and symphysis
pubis
 Normally, the obstetrical conjugate measures 10 cm or more

8. ii) Transverse Diameter
 Widest diameter along the linea terminalis: 13 cm.
 The transverse diameter is constructed at right angles to the
obstetrical conjugate and represents the greatest distance
between the linea terminalis on either side.
 This intersects the obstetric conjugate at right angles 4 cm in
front of sacral promontory.
iii) Oblique Diameter:
 From sacro-iliac joint to iliopectineal eminence: 12 cm.
 Each of the oblique diameters extends from one of the
sacroiliac synchondroses to the iliopectineal eminence on the
opposite side of the pelvis.
 They are designated right and left, according to whether they
originate at the right or left sacroiliac synchondrosis.
2. MIDPELVIS (MID-CAVITY)
 At the Mid-Cavity, the least accepted diameters are:
i) Anteroposterior Diameter

9.  From junction of 2nd & 3rd sacral vertebrae and mid-pubic
symphysis: 12 cm.
ii) Transverse diameter:
 The transverse diameter is 12 cm.
 The distance between the interspinous and the sacral
promontory is 4.5 cm.
 Engagement of foetal head means that it is at the level of
ischial spines.
3. PELVIC OUTLET
 At the Outlet, the least accepted diameters are:
i) Anteroposterior Diameter
 From lower pubic symphysis border to 5th sacral vertebrae: 13
cm.
 The anteroposterior diameter (9.5 to 11.5 cm) extends from the
lower margin of the symphysis pubis to the tip of the sacrum
ii) Transverse diameter
 Intertuberous diameter: 11 cm.

10.  The transverse diameter (11 cm) is the distance between the
inner edges of the ischial tuberosities
iii) Oblique diameter:
 Mid point of the sacrotuberous ligament: 12 cm.
 The distance between tip and sacrum to line joining Ischial
Tuberosities is 7.5cm.
 The posterior sagittal diameter extends from the tip of the
sacrum to a right-angle intersection with a line between the
ischial tuberosities.
 The normal posterior sagittal diameter of the outlet usually
exceeds 7.5 cm
 The intertuberous diameter or bisischial diameter is < 8-10cms
in length.
 This can be measured by Thomas pelvimeter or by applying 4
finger knuckles.
 In obstructed labors caused by a narrowing of the midpelvis or
pelvic outlet, the prognosis for vaginal delivery often depends
on the length of the posterior sagittal diameter of the pelvic
outlet
Pelvic planes
 The pelvic planes are imaginary lines drawn from the brim,
cavity and outlet which subtends with the horizontal passing
through the pubis symphysis when one is standing. They are:

11. 1. Plane of pelvic brim = 60°
2. Plane of pelvic cavity = 30°
3. Plane of pelvic outlet = 15°
Types of Pelves
A. Gynecoid
 In pure form, the gynecoid pelvis provides a rounded, slightly
ovoid, or elliptical inlet with a well-rounded forepelvis (anterior
segment).
 The bones are primarily of medium weight and structure.
B. Android
 The android pelvis has a wedge-shaped inlet, a narrow
forepelvis, a flat posterior segment, and a narrow sacrosciatic
notch, with the sacrum inclining forward.
 The side walls converge, and the bones are medium to heavy in
structure.
C. Anthropoid
 The anthropoid pelvis is characterized by a long, narrow, oval
inlet; an extended and narrow anterior and posterior segment; a

12. wide sacrosciatic notch; and a long, narrow sacrum, often with 6
sacral segments.
D. Platypelloid
 The platypelloid pelvis has a distinct oval inlet with a very wide,
rounded retropubic angle and a wider, flat posterior segment.
The differences between female & male pelvis
1. The vertical height is less in female.
2. Sub-pubic angle is greater in the female.
3. Female sacrum is shorter, wider, less curved
4. Female Ischial spines are less prominent and less curved.
5. Height of pubic symphysis is less in females
6. Greater sciatic notch and wider in females
7. Distance between symphysis pubis and anterior margin of
acetabulum is greater in females than in males.
FETAL SKULL
Diameters
A. Suboccipital-Bregmatic Diameter (9.5 cm)

13.  It follows a line drawn from the middle of the anterior
fontanelle to the undersurface of the occipital bone just where
it joins the neck.
 In full flexion the suboccipito-bregmatic diameter presents.
(Vertex presentation)
B. Occipital-Frontal Diameter (11.5 cm)
 A line extending from a point just above the root of the nose to
the most prominent portion of occipital bone.
 Suboccipital-frontal is 10.5 cm
C. Submento–Bregmatic Diameter (9.5 cm)
 It extends from below the Chin to the centre of the Anterior
Fontanelle (Bregma). (Face presentation).
 Spontaneous delivery can occur with mento-anterior although
with some difficulties because the facial bones do not mold as
easily.
D. Mento–Vertical Diameter (13.5 cm)
 From point of the Chin to the centre of the Posterior Fontanelle.
(Brow presentation)
E. Biparietal Diameter (9.5 cm)

14.  The greatest transverse diameter of the head, which extends
from one parietal eminence to the other
F. Bitemporal Diameter (8.0 cm)
 The greatest distance between the two, (Left and Right)
Temporal Sutures.
Circumferences
A. Suboccipito-Bregmatic x Biparietal Circumference (28 cm)
 These are the engaging diameters of a well-flexed Vertex
presentation. During normal labor, fetal head flexion is essential
for passage (engagement and descent) of the smallest diameter

15. and circumference of the head through the smallest diameter of
the bony pelvis. (The smallest circumference < 28cm and is
subtended by Suboccipital-Bregmatic diameter and Biparietal
diameter).
 The engagement and descent is further aided by fetal muscle
tones, uterine shape and uterine contractions.
B. Occipital-Frontal x Biparietal Circumference. (33 cm)
 These are the engaging diameter of deflexed vertex
presentation and found in occipital posterior positions.
C. Mento-Vertical x Biparietal Circumference. (35.5 cm)
 The largest circumference of the head and is found in bipod
presentation.
Placental Types
A. Circumvallate (Circummarginate) Placentas
B. Succenturiate Lobe
C. Bipartite Placenta
D. Marginal Insertion of Cord (Battledore Placenta)
E. Placenta Membranacea
F. Placenta Accreta
G. Placenta Previa

16. H. Multiple Pregnancy Placenta
CONTENTS OF THE PELVIC CAVITY
 The organs that occupy the female pelvis are the bladder, the
ureters, the urethra, the uterus, the uterine (fallopian) tubes or
oviducts, the ovaries, the vagina, and the rectum
Vagina
Anatomy
 The vagina is a fibromuscular canal that extends from the
uterus to the vestibule of the external genitalia, where it opens
to the exterior
 The anterior wall of the vagina is about 8 cm long and the
posterior wall about 10 cm long.
 It meets the cervix of the uterus at an angle of 45-90 degrees.
 Because the cervix of the uterus projects into the upper portion,
the anterior wall of the vagina is 1.5-2 cm shorter than the
posterior wall.
 Toward its lower end, the vagina pierces the urogenital
diaphragm and is surrounded by the 2 bulbocavernosus
muscles and bodies, which act as a sphincter (sphincter
vaginae).

17. Arteries, Veins, Lymphatics & Nerves
 Arteries: vaginal branch of the internal iliac artery, vaginal
branch of the uterine artery, branches of the middle and
inferior hemorrhoidal arteries
 Veins: The veins follow the course of the arteries.
 Lymphatics: External iliac nodes, Hypogastric channels &
inguinal nodes
 Nerves: The upper two-thirds of the vagina are pain insensitive
and are supplied by sympathetic L1, L2 and parasympathetic
segments S2, S3 nerves derived from the inferior hypogastric
and uterovaginal plexuses. Sympathetic nerves are
vasoconstrictor and parasympathetic nerves vasodilator. The
lower one-third of the vagina is pain sensitive and is supplied
by the pudendal nerve through the inferior rectal and posterior
labial branches of the perineal nerve.
Relationships
 Anteriorly: bladder, ureters, and urethra
 Posteriorly: rectovaginal pouch, rectum, perineal body
 Laterally: broad ligament, levator ani, transverse cervical
ligament, pubococcygeus, urogenital diaphragm, bulb of the
vestibule, the bulbospongiosus and the greater vestibular gland
of Bartholin

18.  Supports: bulbocavernosus muscles and bodies, levator ani
(puborectalis), transverse (cardinal) ligaments of the uterus.
The uterus
Size and Shape
 The uterus is pyriform in shape.
 It is about 7.5 cm long, 5 cm broad and 2.5 cm thick.
 It weighs 30 to 40 grams.
Normal Position and Angulation
 Normally, the long axis of the uterus forms an angle of about
90 degrees with the long axis of the vagina.
 The forward bending of the uterus relative to the vagina is
called anteversion
 The uterus is also slightly flexed on itself: this is referred to as
anteflexion.
 The angle of anteflexion is 125 degree
 Communications: Superiorly, the uterus communicates on each
side with the uterine tube, and inferiorly with the vagina.
 The fertilized oocyte is usually implanted in the posterior wall of
the fundus
 The anterior or vesical surface is flat and related to the urinary
bladder.

19.  The posterior or intestinal surface is convex and is related to
coils of the terminal ileum and to the sigmoid colon.
 Each lateral border is rounded and convex. It provides
attachment to the broad ligament of the uterus which connects
it to the lateral pelvic wall.
 The uterine tube opens into the uterus at the upper end of this
border.
 The uterine artery ascends along the lateral border of the
uterus between the two layers of the broad ligament
Cervix of Uterus
 The cervix is the lower, cylindrical part of the uterus.
 It is less mobile than the body.
 It is about 2.5 cm long, and is slightly wider in the middle than
at either end.
 The lower part of the cervix projects into the anterior wall of
the vagina which divides it into supravaginal and vaginal parts.
 The supravaglnal part of the cervix is related: (a) Anteriorly to
the bladder; (b) posteriorly to the rectouterine pouch,
containing coils of intestine and to the rectum and (c) on each
side to the ureter and to the uterine artery, embedded in
parametrium.
 The fibrofatty tissue between the two layers of the broad
ligament and below it is called the parametrium.
 It is most abundant near the cervix and vagina.

20.  The vaginal part of the cervix projects into the anterior wall of
the vagina. The spaces between it and the vaginal wall are
called the vaginal fornices. In a nulliparous woman, i.e. a
woman who has not borne children, the external os is small and
circular.
 However, in multiparous women, the external os is bounded by
anterior and posterior lips, both of which are in contact with
the posterior wall of the vagina.
 The broad ligament contains the following structures
1. The uterine tube
2. The round ligament of the uterus.
3. The ligament of the ovary.
4. Uterine vessels near its attachment to the uterus.
5. Ovarian vessels in the infundibulopelvic ligament.
6. The uterovaginal and ovarian nerve plexuses.
7. Epoophoron.
8. Paroophoron.
9. Some lymph nodes and lymph vessels.
10. Dense connective tissue or parametrium present on the
sides of the uterus.
 The fibromuscular ligaments are:
1. Round ligaments of the uterus:
2. transverse cervical ligaments; and
3. Uterosacral ligaments.
Arterial Supply

21.  The uterus is supplied:
1. Chiefly by the two uterine arteries a branch of the anterior
division of the internal iliac artery
2. Partly by the ovarian arteries
Venous Drainage
 The veins form a plexus along the lateral border of the uterus.
 The plexus drains through the uterine, ovarian and vaginal veins
into the internal iliac veins.
Lymphatic Drainage
 Lymphatics of the uterus begin at three intercommunicating
networks endometrial, myometrial and subperitoneal.
 These plexuses drain into lymphatics on the side of the uterus.
 Of these, the upper lymphatics from the fundus and upper part
of the body drain mainly into the aortic nodes, and only partly
to the superficial inguinal nodes along the round ligament of
the uterus.
 The lower lymphatics from the cervix drain into the external
iliac, internal iliac and sacral nodes.
 The middle Iymphatics from the lower part of body drain into
the external iliac nodes.

22. Nerve Supply
 The uterus is richly supplied by both sympathetic and
parasympathetic nerves, through the inferior hypogastric and
ovarian plexuses.
 Sympathetic nerves from T12, L1 segment of spinal cord
produce uterine contraction and vasoconstriction.
 The parasympathetic nerves (S2, S3, S4) produce uterine
inhibition and vasodilatation.
Uterine (Fallopian) Tubes (Oviducts)
Anatomy
 The uterine tubes serve to convey the ova to the uterus
 They extend from the superior angles of the uterus to the
region of the ovaries, running in the superior border of the
broad ligament (mesosalpinx).
 Each tube is 7-14 cm long and may be divided into 3 parts:
isthmus, ampulla, and infundibulum.
 The isthmus is the narrow and nearly straight portion
immediately adjoining the uterus.
 It has a rather long intramural course, and its opening into the
uterus, the uterine ostium is approximately 1 mm in diameter.
 Following the isthmus is the wider, more tortuous ampulla.
 It terminates in a funnel-like dilatation, the infundibulum.

23.  The margins of the infundibulum are fringed by numerous
diverging processes, the fimbriae, the longest of which, the
fimbria ovarica, is attached to the ovary
Layers of Wall
 The wall of the tube has 4 coats: serous (peritoneal), subserous
or adventitial (fibrous and vascular), muscular, and mucous.
 The muscular coat has an outer longitudinal and an inner
circular layer of smooth muscle fibers, more prominent and
continuous with that of the uterus at the uterine end of the
tube
 The mucous coat is ciliated columnar epithelium
Ligament
 The infundibulum is suspended from the pelvic brim by the
infundibulopelvic ligament (suspensory ligament of the ovary).
 This portion of the tube may adjoin the tip of the appendix and
fuse with it.
Arteries & Veins
 The blood supply to the tubes is derived from the ovarian and
uterine arteries
 The veins accompany the arteries

24. Lymphatics
 The lymphatic drainage occurs through trunks running
retroperitoneally across and anterior to the ureter, into the
lumbar nodes along the aorta, and inferior to the kidney.
Nerves
 The nerve supply is derived from the pelvic plexuses
(parasympathetic and sympathetic) and from the ovarian plexus
Ovaries
Anatomy
 The ovaries are paired organs situated close to the wall on
either side of the pelvis minor, a little below the brim.
 Each measures 2.5-5 cm in length, 1.5-3 cm in breadth, and 0.7-
1.5 cm in width, weighing about 4-8 g
Relationships
 The upper portion of this surface is overhung by the fimbriated
end of the uterine tube, and the remainder lies in relation to
coils of intestine.

25.  The lateral surface is similar in shape and faces the pelvic wall,
where it forms a distinct depression, the fossa ovarica.
 This fossa is lined by peritoneum and is bounded above by the
external iliac vessels and below by the obturator vessels and
nerve; its posterior boundary is formed by the ureter and
uterine artery and vein, and the pelvic attachment of the broad
ligament is located anteriorly.
 The mesovarian or anterior border is fairly straight and provides
attachment for the mesovarium, a peritoneal fold by which the
ovary is attached to the posterosuperior layer of the broad
ligament.
 Since the vessels, nerves, and lymphatics enter the ovary
through this border, it is referred to as the hilum of the ovary.
 Anterior to the hilum are embryonic remnants of the male and
female germ cell ducts The posterior or free border is more
convex and broader and is directed freely into the rectouterine
pouch.
 The upper or tubal pole is large and rounded.
 It is overhung closely by the infundibulum of the uterine tube
and is connected with the pelvic brim by the suspensory
ligament of the ovary, a peritoneal fold.
 The lower or uterine pole is smaller and directed toward the
uterus. It serves as the attachment of the ligament of the ovary
proper.
Mesovarium

26.  The ovary is suspended by means of the mesovarium, the
suspensory ligament of the ovary, and the ovarian ligament
Vasculature
 Arteries:ovarian artery as branches of the abdominal aorta, the
left frequently originates from the left renal artery
 Veins: follow the course of the arteries and, as they emerge
from the Hilum, form a well-developed plexus (the pampiniform
plexus) between the layers of the mesovarium
 Lymphatics: Lymphatic channels drain retroperitoneally,
together with those of the tubes and part of those from the
uterus, to the lumbar nodes along the aorta inferior to the
kidney
 Nerves: lumbosacral sympathetic chain and passes to the
gonad along with the ovarian artery.
Bladder
Relationships
 Anterior: pubic bones
 Superior: peritoneum
 Posteriorly: vesicouterine pouch, uterus, broad ligament, cervix,
anterior fornix of the vagina

27. Arteries, Veins, Lymphatics & Nerves:
 Superior vesical artery from umbilical artery, a terminal branch
of the hypogastric artery
 Middle vesical artery from superior vessels or umbilical artery
 Inferior vesical artery from hypogastric artery
 The fundus may also receive small branches from the middle
hemorrhoidal, uterine, and vaginal arteries.
 Veins form an extensive plexus at the sides and base of the
bladder from which stems pass to the hypogastric trunk.
 Lymphatics: hypogastric nodes
 Nerves: Hypogastric sympathetic plexus and partly from the
second and third sacral nerves (the nervi erigentes)
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