2. Morphology of Umbilical Cord
It is the connection between placenta and
fetus.
• Length: 50 – 60 cm
• Diameter: 2 cm.
• Shape: Tortous, showing false notes.
• Contents: 2 umbilical arteries, one umbilical vein
embedded in wharton’s jelly and surrounded by
amniotic membrane.
• Attachments: It is attached to fetal surface of placenta
near its center, the other attachment is to ventral
aspect of fetal abdominal wall.
• Functions:
– It contains umbilical vessels that connect the fetus to the
placenta.
Dr. Sherif Fahmy
5. Development of the Cord
• Primitive umbilical ring:
- Expansion of amniotic cavity, leads to folding with
ventral shifting of amnio-ectodermal junction and
formation of primitive umbilical ring
- Contents:
-Connecting stalk containing allantois and umbilical
vessels.
-Vitelline duct and vitelline vessels.
-Connection between intraembryonic and extra-
embryonic coelom.
Dr. Sherif Fahmy
6. Primitive umbilical cord:
- Expansion of amniotic cavity, leads to
elongation of umbilical cord.
Contents:
1- Yolk sac and vitelline duct.
2- Connecting stalk with remnant of allantois.
3- Intestinal loop in its proximal part.
4- Umbilical and vitelline vessels.
Dr. Sherif Fahmy
7. Definitive umbilical cord:
- Return of intestinal loop to abdominal cavity at
3rd
month.
-Obliteration of vitelline duct, allantois, extra-
embryonic part of vitelline vessels.
-Degeneration of one umbilical vein with
persistence of other vein and 2 umbilical
arteries.
-Transformation of mesoderm of connecting
stalk into wharton’s jelly.
17. • Abnormalities of Umbilical Cord
• 1- Short cord: leads to premature separation
of placenta.
• 2- Long cord: It may encircle neck of fetus and
may form true knots.
• 3- Congenital umbilical hernia
(omphalocele): the cord contains coils of
intestine.
• 4- Presence of one umbilical artery.
• 5- Abnormal attachment of the cord:
–Marginal attachment (battledore)
–Through membranes (velamentous).
Dr. Sherif Fahmy
22. Types of TWINS
Dizygotic (Fraternal) twins:
- It is the commonest type as it represent 2/3 of
twins and 7 – 11 / 1000 births.
- Fertilization of 2 separate ova.
- Each embryo has its own placenta, chorion
and amniotic cavity.
- Twins are non-identical and may of same sex
or different.
Dr. Sherif Fahmy
23. Monozygotic (Identical) twins:
Developed from division of a fertilized ovum. Twins of this type are
identical and of same sex. Its incidence is 0.3 – 0.4 %
Division may occure at 3 different stages:
1- At morula stage: Twins has separate amnion,
chorion and placentae (as in dizygotic).
2- At blastocyst stage: due to division of inner cell
mass. Twins has separate amniotic cavity but single
chorion and placenta.
3- At embryonic disc: Midline division of the embryonic
disc. Twins has common amniotic cavity, common
chorion and common placenta .
Dr. Sherif Fahmy
25. SIAMESE (CONJOINED) TWINS
• Fused monozygotic twins that occurs
due to incomplete separation of
emberyonic disc. They could be
either:
Craniopagus: Fusion between 2 heads.
Thoracopagus: Fusion at thoracic region.
Pygopagus: Fusion at the pelvic region.
Dr. Sherif Fahmy
31. 1- Numerical Chromosomal Anomalies
A-Autosomal:
• A- Triosomy 21 (Down or Mongolism).
• Each cell contains 47 chomosomes (45 + XX or
XY).
• B- Triosomy 13, 15, 17 & 18.
Dr. Sherif Fahmy
32. B- Sex Numerical Chromosomal Anomalies
• 1- Klinefelter syndrome: (44 + XXy)
Due to non-disjunction of X chromosome. Male
case suffers from infertility and gynecomastia.
• 2- Turner syndrome: (44 + X0)
Due to non-disjunction of X chromosome.
Female case suffers from gonadal dysgenesis,
short staure and neck skin fold
Dr. Sherif Fahmy
33. 2- Structural Chromosomal Anomaly
• A- Cri-du-Chat Syndrome.
Due to partial deletion of short arm of
chromosome 5 (cat-like cry, microcephaly and
mental retardation).
• B- Angelman Syndrome.
Partial deletion of long arm of chromosome 15
(mental retardation, poor motor development
and prolonged period of laughter.
Dr. Sherif Fahmy
40. A Child of A Mother Treated by
Antiepileptic drug
41. A Child of A Mother Treated with
Antithyroid drug
42. A Child of A mother Exposed to
Rubella Infection
43. External Appearance of the Embryo
(4th
– 8th
week)
At the embryonic period (4th
– 8th
week),
human shape becomes easily identified.
-Head, body and limb buds are easily
identified.
-Eyes, nose and ears are seen.
44. C-R length in mms Age of embryo in weeks
5 – 8 5
10 – 14 6
17 – 22 7
28 – 30 8
46. C-R length in cm Age of embryo in months
5 – 8 cm 3rd
month
18 cm 5th
month
36 cm Full term fetus at birth
47. Relative size of head to body:
-At the beginning of the 3rd
month, the head is ½
the CR length.
-At the beginning of the 5th
month, the head is 1/3
the CH length.
-At birth, the head is ¼ of CH length.
Weight growth:
-At the end of 5th
month, the weight is ½ kg.
-At the 7th
month, the weight is 1.75 kg.
-At full term, the weight is 3.5 kg.
48. Changes in external features:
-Face becomes human looking.
-Limbs become longer.
-External genitalia are differentiated at 12th
week.
-Lanugo hair covers the fetus since the 4th
month.
-The skin is wrinkled till the end of 6th
month.
-Testes descend to scrotum just before birth.
-Skin is covered by fatty substance called vernix
caesosa.
Fetal movement:
It is clearly recognized since the 5th
month.
