Fetal Skull And Circulation Ppt 4s354w

Fetal Skull Development 

Develops from the mesoderm and the neural crest.  By end of the 4th week loosely woven tissue – embryonic connective tissue  Differentiation of cells within the skull is different. The flat bones ossifies from the membrane. Whist other bones form cartilage after which ossification takes place

Fetal Skull Development  

Skull is divided into 2 parts: Neurocranium –protecting the brain which is known as the vault. This is subdivided into: 1. Dermatocranium – parietal & frontal 2. Chondrocranium –occipital, temporal, sphenoid – base of the skull. Fusion of cartilage  Viscerocranium – forms the face – starts with the mandible at 6 weeks gestation

Fetal Skull  29 bones  8 form the cranium  14 form the face  7 form the base

The vault of the skull comprises  Two frontal bones  Two parietal bones  One occipital bone  Two temporal bones.

Sutures

 Lambdoidal suture: separates the occipital bone from the parietal bones  Sagital suture: lies between 2 parietal bones  Coronal suture: separates frontal bones from

parietal bones  Frontal suture:runs between two halves of

frontal bones

 Anterior fontanelle /bregma:

Found at junction of sagital coronal and frontal suture. Broad, diamond shaped.

3-4 cm long and 1.5 – 2cm wide. Closes at 18 months

Fontanelles.

 Posterior fontanelle or lambda: located at junction of lambdoid and sagital sutures.  Triangular  Closes by 6 weeks of age

Diameters of fetal skull:  Biparietal diameter : this is 9.5 cm . this is the

diameter between two parietal eminences.  Bitemporal diameter: this is 8.2 cm-

diameter between the furthest points of the coronal suture at the temples.

 Super sub parietal -8.5 cm. – it extends from a

point placed below one parietal eminence to a point placed above the other parietal eminence. Of the opposite side.  Bi-mastoid diameter-7.5cm- it is the distance

between the tips of the mastoid processes. The diameter is incompressible and it is impossible to reduce the length of the bimastoid diameter by obstetrical operation.

 Suboccipitobregmatic: This is 9.5 cm, the

diameter from below the occipital protuberance to the centre of the anterior fontanelle or bregma.  Suboccipitofrontal: This is 10 cm- the

diameter from below the occipital protuberance to the center of the frontal suture  Occipitofrontal: This is 11.5 cm- the diameter

from the occipito protuberance to the glabella.

 Mentovertical: This is 13.5 cm- the diameter

from the point of the chin to the highest point on the vertex  Submentovertical: This is 11.5 cm- the diameter from the point where the chin s the neck to the highest point on the vertex.  Submentobregmatic: This is 9.5 cm-the

diameter from the point where the chin s the neck to the centre of the bregma.

MOULDING OF THE HEAD  Occurs with descent of the fetal head into the

pelvis to reduce the head circumference  Frontal bones slip under parietal bones  Parietal bones override each other

 Parietal bones slip under the occipital bone

MOULDING OF THE HEAD DEGREE OF MOULDING Assessed vaginally  0 suture lines are separate  +1  suture lines meet  +2  suture lines overlap but can be reduced by gentle digital pressure  +3  overlap irreducible

Caput succedaneum

Cephal hematoma



Fetal circulation

 The fetal circulation differs mainly from the

adult ones by the presence of 3 major vascular shunts. Ductus venosus: between umbilical vein and inferior venacava Foramen ovale: Between the right and left atrium Ductus arteriosus: Between the pulmonary artery and descending aorta.

1. The umbilical vein transports blood rich in

oxygen and nutrients from the placenta to the fetal body. This vein travels along the anterior abdominal wall of the fetus to the liver, and then the umbilical vein divides into branches. 2. About half of the blood es into the liver and the rest enters a shunting vessel called ductus venosus that byes the liver. The ductus

venosus travels a short distance and s the inferior venacava.

3. There the oxygenated blood from the placenta

is mixed with deoxygenated blood from the lower parts of the fetal body. This blood continues through the venacava to the right atrium. 4. As the blood relatively high in oxygen enters

the right atrium of the fetal heart, a large proportion of it is shunted directly into the left atrium through an opening in the atrial septum called the foramen ovale.

5. The more highly oxygenated blood that

enters the left atrium through the foramen ovale is mixed with a small amount of deoxygenated blood returning from the pulmonary veins. This mixture moves into the left ventricle and is pumped into the aorta. 6. Some of this blood reaches the myocardium

by means of coronary arteries. And some reaches the tissues of the brain through the carotid arteries.

7. The rest of the blood entering the right atrium,

as well as the large proportion of the deoxygenated blood entering from the superior venacava, es into the right ventricle and out through the pulmonary artery 8. Enough blood reaches the lung tissue to

sustain them. Most of the blood in the pulmonary artery byes the lungs by entering the ductus arteriosus, which connects the pulmonary artery to the descending portion of the aorta arch

9. Some of the blood carried by the descending

aorta leads to various parts in the lower regions of the body. 10. The rest of the blood es into the umbilical

arteries which branch from internal iliac arteries and lead to the placenta.

 REVIEW OF LITERATURE  Noninvasive Assessment of the Early

Transitional Circulation in Healthy Term Infants.  Author: Popat H, Kluckow M.  Source

 Department of Neonatology, Royal North Shore Hospital and University of Sydney, Sydney, N.S.W., Australia.

 Abstract

 Background: The early neonatal circulatory transition usually occurs smoothly but occasionally it is incomplete or reverts to the

fetal state of high pulmonary vascular resistance, resulting in significant neonatal morbidity.

 Objective: To define the normal values for

echocardiographic parameters during the early transitional circulation in term infants.

 Methods: Two-dimensional, M-mode, pulsed

and color flow Doppler echocardiography was used to assess healthy term infants in the first 4

h of life. Left and right ventricular outputs (LVO and RVO) and myocardial performance indices

(MPI), left ventricular fractional shortening, endsystolic diameter and end-diastolic diameter, ductal size, shunt and peak velocities, tricuspid regurgitation and left pulmonary artery diastolic velocities were documented.

 Results: A total of 21 normal term infants were

assessed with median gestation of 39 weeks, birth weight of 3,470 g and postnatal age of 3 h and 22 min. The median echocardiographic values were LVO 193

ml/kg/min, RVO 216 ml/kg/min, left MPI 0.41, right MPI 0.63, and fractional shortening 29%. The ductus was patent in all 21 infants with a median size of 2.3 mm; ductal flow was bidirectional in 86% with median peak left-to-right velocity of 1.07 m/s. The median left pulmonary artery diastolic velocity was 0.31 m/s and physiological tricuspid regurgitation was present in all infants.

 Conclusion: This study defines normal values for

echocardiographic measurements in healthy term infants during the first 4 h after birth.

These normative data may be useful in early identification of infants with abnormal

circulatory transition, allowing more rapid determination of cardiovascular dysfunction.

 2. journal of reproductive medicine. 1976

Jun;16(6):321-4.  Intrauterine spontaneous depression of fetal

skull: a case report and review of literature.  Author: Guha-Ray DK.

 Abstract  Intrauterine depression of fetal skull, with or

without fracture, unassociated with any known trauma during pregnancy or delivery, is extremely rare in Western countries though not so rare in Africa among African women. Usually fetal skull depression is caused by forceps or digital pressure of the obstetrician during manual rotation.

 Forty such cases are reported in the literature-

nine in Western countries and the remaining 31

over a period of three years at Harare Hospital Maternity Centre, Salisbury, Rhodesia, Africa.

There, an incidence of one in 4,000 deliveries was observed among the African women but

none in 6,000 deliveries of European women during the same period at a nearby hospital.

 The presentation of this paper is made in view

of the rarity of intrauterine spontaneous fetal skull depression in Western countries and the not so infrequent occurrence in African and possibly other developing countries and

because of the persistent controversy about the treatment of this condition.

 3.child’s nervous system:ChNS: Official journal





 

of the international society for pediatric neuro surgery . 1996 Feb;12(2):117-20. Craniocerebral birth trauma caused by vacuum extraction: a case of growing skull fracture as a perinatal complication. AUTHOR: Papaefthymiou G, Oberbauer R, Pendl G. Source Universitäts-Klinik für Neurochirurgie, KarlFranzens-Universität Graz, Austria.

 Abstract  A case of growing skull fracture following birth

trauma and caused by vacuum extraction is reported in order to emphasize the incidence of this peculiar head injury at the beginning of extrauterine life and to point out its relation to possible neuropsychological disturbances that

may appear later in childhood.

 Delivery by vacuum extraction increases the

incidence of perinatal injuries and consequently the incidence of neurological deficits in children.

Neurosurgical repair is advocated as the appropriate treatment, with the aim not only of

cosmetically correcting the lesion's typical subgaleal protuberance with cranioplasty, but also of performing a water-tight closure of the dura, enabling the cerebral cortex to "fill in" the intracerebral lesion

 The surgical technique and gross pathology of the

lesion are described together with radiological findings before and after surgery. Reports by other authors are reviewed in an attempt to identify the

conditioning factors and pathological features of this traumatic injury to skull and brain in neonates and infants. The literature on cranial fractures associated with intracerebral lesions at this age shows a significant difference in recovery and outcome from that after similar lesions in older children.

Bibliography  Brian Magowan, Philip Owen, James Drife, Clinical

obstetrics and gynecology, second edition, Edinburgh. Elseviers Ltd. 2009

 D. C Dutta Textbook of obstetrics including

perinatology and contraception, 6th edition. Culcutta. Published by new central book agency private Ltd.

 Diane M Fraser, Margerett A Cooper. Myles

textbook of midwives. 15th edition. London. Elsevier publication 2009

 Holland and Brews. Manual of obstetrics , updated by

Shirish N Daftary, Sudip Chakravarthy 3rd edition . Chennai. Elsevier India pvt ltd 2011.

   Kamini Rao. Textbook of midwifery and obstetrics for

nursing . Newdelhi. Elseviers publication 2011

  Oa Ojo Enang Bassery Briggs . A textbook for midwives

in the tropics. 2nd edition. Newdelhi Jaypee brothers pvt ltd.

  Lowdermilk , Perry. Matternity Nursing 7th edition .

Missouri; Elseviers Pvt Ltd 1983.

 