UMBILICAL CORD

Dr. Sherif Fahmy

Morphology of Umbilical CordIt 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.– Allows free mobility of the fetus.

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

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

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

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.

Development

Embryonic disc with removed ectoderm

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

• 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

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

TwinsDr. Sherif Fahmy

Types of TWINSDizygotic (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

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

Morula

stageEmbryonic Disc StageEarly

blastcyste

Dr. Sherif Fahmy

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

Conjoined Twines

Dr. Sherif Fahmy

Birth DefectsDr. Sherif Fahmy

Dr. Sherif Fahmy

1- Enviromental Factors• Infectious Agents: Viruses, Bacteria and

parasites.• Radiations: X-ray, Gamma and atomic

radiation.• Drugs & chemicals: e.g. antiepileptic drugs,

vit. A, Alcohol• Maternal diabetes:

Dr. Sherif Fahmy

Chromosomal

1- Numerical Chromosomal AnomaliesA-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

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

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

Down Syndrome

Dr. Sherif Fahmy

Cri du Chat Syndrome

Turner Syndrome

Achondroplasia

A Child of Alcoholic Mother

A Child of A Mother Treated by Antiepileptic drug

A Child of A Mother Treated with Antithyroid drug

A Child of A mother Exposed to Rubella Infection

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.

C-R length in mms Age of embryo in weeks

5 – 8 5

10 – 14 6

17 – 22 7

28 – 30 8

Fetal Period

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

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.

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.

The End & Beginning

With my best wishes Dr. Sherif

Fahmy