Structure and function
-Umbilical cord is covered by amnion and contains a
single umbilical vein, and two umbilical arteries
supported in Wharton jelly.
-Amnion covers the umbilical cord except near the
fetal insertion, where an epithelial covering is
-The arteries wind around the umbilical vein in a
spiral fashion and, because the vessels are longer
the cord itself, there are a number of foldings or
tortuorties producing protusions or false knots on
the cord surface.
-The Wharton jelly protects the vessels from undue
torsion and compression.Aboubakr Elnashar
Sonographic anatomy of umbilical cord
-late 1st T
-The umbilical stalk may occasionally be seen,
adjacent to the anterior abdominal wall of the fetus.
2nd and 3rd T:
cord is much more readily visualized.
a portion of cord will be seen as a series of parallel
lines and sometimes the spiral course of umbilical
arteries can be demonstrated.
arteries and veins will be seen as three separately
circular lucencies. Normally: Two arteries & one
vein. Aboubakr Elnashar
Umbilical Cord in
Cross Section Aboubakr Elnashar
By scanning near the center of placenta, the
insertion site of the cord may be demonstrated as
sonolucent area adjacent to the chorionic plate.
At the insertion of the cord into the anterior
abdominal wall of the fetus, the origin of umbilical
vein and hypogastric arteries may be seen.
anterior to the fetal abdominal wall and adjacent to
Nucal: around fetal neck
Between the fetal presentation part and the lower
uterine segment (funic presentation). more common
with malpresentations such as breech or transverse
The normal umbilical cord extends from the
placenta to the fetal umbilicus, twisting (coiling) as
it traverses the distance between these two points.
The umbilical cord contains two umbilical arteries
and an umbilical vein which are normally coiled.
1. Single umbilical artery (SUA)
1% of all singleton births
5% of twins
2.5% of abortuses.
80% normal fetus.
20 % others abnormalities (urinary - Ht - GIT &
Ext. ear karyotyping is mandatory if abnormality
complete parallel course of umbilical artery and vein
only two circular lucencies
TS: normal umbilical cord. Clearly
visible is the large-bore umbilical
vein and two smaller bore vessels
which are the umbilical arteries.
TS: the vessel with only one artery.
Hypocoiled umbilical cord
Uncoiling or hypocoiled umbilical arteries are associated with increased fetal
morbidity, including small for gestational age babies (fetuses).
an almost straight umbilical cord with almost no coils (hypocoiled cord). Such
ultrasound findings are also associated with increased incidence (almost 64 %)
of abnormal umbilical cord insertions, ie: marginal or velamentous
4. Nucal position
Single is safer than multiple umbilical cord loops
around the fetal neck.
Two types of cord loops around the fetal neck
umbilical nuchal cord encircles the fetal neck in a
sliding manner (less dangerous)
nuchal cord encircles the neck in a locking manner
a 360 degree loop around the neck
Sagittal section: a single loop of umbilical
cord ( arrowheads) around the neck.
single cord loop posteriorly- The color
Doppler images suggest a single loop of
cord in a sliding manner.Aboubakr Elnashar
Antenatal ultrasonogram showing umbilical cord around
the fetal neck (axial section) in a 25 weeks pregnancy
A sonographically detected nuchal cord is not
associated with important perinatal complications.
umbilical cord prolapse
21 week gestation had labour contractions with leaking per
vaginum. On color doppler scan, the internal os appears dilated
with umbilical cord seen within the cervix.
umbilical vein varix
a cystic lesion in the umbilical cord close to the fetal abdomen.
On color doppler scan, flow is present in the cystic area which
shows continuity with the umbilical vein.