الفهرس 
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Abstract
Development of hwnanembryo is a complex, and evolurive process that requires accurate evaluation to detect any fetal malformation that may result in ethalor morbid outcome of pregnancy. Early and accurate antenatal diagnosis of fetal mosco.l.oskeleroI malformations and differentiation between a lethal and a non-lethal varieety has important implications for the managementofa pregnancy and prediction of fetal outcome.Il.ee e,l al. 2002 Three-dimensionel sonography revolutionized
ultrasound imaging with its capacity to depict an unlimited
number of planes in which the objec-t of interest can ’be
displayed. The development of numerous computed modes
of image rendering promotes three-dirnensionejsonography
inobstetrics and gyneooIogy. The main advantage of threedimensional
(3D) ultrasound in prenatal medicine and
antenatal diagnosis indude scanning in the coronal plane,
improved assessment of complex anatomic structures.
sutfaceanalysis of minor de ects, volumetric measuring of
organs, transparent imaging of fetal skeleton, spatial
presentation of blood dow arborization. and, finally,. storage
of scanned volume and images. Three-.dtm.eosionall
sonography has gained a valuable place in prenatal diagnosis.becoming a necessity for every modem perinatal unit.
(Korjak et a], 2000)
This work will review the Iitcratllrcconcemoo with
abnormalities of fetal skeleton and extremities including
skeletal. dysplaslas and spine malformations. Previous
literature concerning different 3D image display modes in
visualizin.g fetal malformations: triplanar orthogonal display;
surface display; and transparent display will be reviewed.
(Merz and Welter, 2008)
Today, every hospital and clinic has some form of
ultrasound instrumentation to provide the clinician with, an
inside look at the soft tissue structures within, the body. The
two dimensional information is now able to be recreated
into a three-dimensional format to provide a surface
rendering of the area in que tion (Hagen, 200 I).
It has boon almost four dec-ades since the first ultrasonic
devices for imaging the fetus were developed.
Conventional B-mode (two dimensional) ultrasound
examination, which has been routinely used for the
evaluation of fdalgrowth and development for more than
two decades, has proved to be a powerful tool in modem
’0bsretrics, Its two major faj lings, have been operator
dependency and the inability to archive and :review a
complete examination. Its utility for dating pregnancies,
assessing fetal growth and in detecting congenital
malfonnations prenatally is well established (Reece and
Chan, 1997).Although very accurate. two dimensional (2D)
ultrasonography is due to phys ieal, anatomical and
topographical reasons, still limited by the rather restricted
number of planes in which the object of Interest can be
depicted, Using 3D ultrasonography it is possible to depict
an unlimited number of’dlfferent planes in which the object
of interest can be displayed (Kos et al, 2002).
bese last years, the use of 3 and mo e recently 4D (life
3D-US) ultrasound has extended greatly and pr-ovides a
clearer image of the fetus, It is used as a complementary
tool to the 2D ultrasound examination of the fetus. It
provides (in selected indications) additional mformation,
especially when searching for dysmorphologic syndromes
(Avni et 31.2006).
The ma}or advantage, OJf 3D, or ”volume” ultrasound, that
it could render US far less operator-dependent, markedly
decrease scanning times, and standardize the entire process
of performing an examination (Benacerraf et al, 2006).
Accurate prenatal diagnosis of skeletal dysplasia. ellows
families to make appropriate decisions for. obstetric
management and delivery. The specific diagnosis of a
skeletal dysplasia in utero requires familiarity with a
complex algorithm of ultrasonogrepbic (US) features.
Although it is often di fficult to determine the specific type
of skeletal dysp,lasia present and whether it is lethal, this
information may be extremely valuable in planning
obstetric care (Kareen et al, 2000).