The Fetal MSK System: Watch the Hands and Feet - HD

Introduction and Objectives

My name is Dr. Beverly Coleman
and today I will be lecturing on
the fetal musculoskeletal system.
Watch the hands and feet.

The objectives of this talk are to emphasize the importance
of more detailed evaluation of the hands
and feet on ultrasound examinations.
I intend to illustrate examples of normal
and abnormal anatomy that we can currently see
with the available ultrasound technology
and also to emphasize an organized approach
to evaluating the hands
and feet, which can assist in diagnosing multiple
musculoskeletal disorders that may be associated with
syndromes and aneuploidy.

Our approach is not only to document the presence
of the four extremities, including the hands and feet,
but we also cover all that you see here.
For example, the number of digits, the size of the digits,
whether there's normal alignment
and we look for specific pathology
and other conditions.

Normal Evaluation of Hands and Feet

Let's start with what is normal.
You probably have not really thought about it, but the hands
and feet are much easier to
evaluate earlier in pregnancy rather than late in pregnancy.
And the reason for that is probably the degree
of intrauterine crowding as the pregnancy advances.
And so the fetus is larger relative
to the amniotic fluid volume with less motion
and the hands and feet can get hidden under body parts
or adjacent to the placenta and the uterine wall.

This table lists much of those skeletal structures
that we can see from the very early part of gestation
to the late third trimester.
Clearly the hands
and feet should be visible in all cases
if normal at approximately 12 to 14 weeks.

Here on this very early transvaginal scan, we can see
that the limb buds are in motion
and there are four buds clearly visible
a little bit later in gestation.
We can see the increase in activity at approximately
12 to 13 weeks.
Notice the movement of the embryo here.

The very first long bone we can measure in pregnancy is
the femur and there are nomograms
from 12 weeks and beyond.

A normal axiom that I would like to point out to you is
that it is really important for there
to be active fetal motion in order
to have normal development of the extremities.
And here we can see the very active motion
of all four extremities in this pregnancy
that is a little bit further along here.

At 14 weeks we can see we get an excellent view
of all five digits on the hands and feet.
And when there is normal motion
and normal fluid, we can capture routinely images
that look like this.

Pitfalls in Evaluation

What are the pitfalls again?
There is intrauterine crowding later in gestation,
which can be problematic.
Also, the fetuses are less active
and they can transiently be in a fixed position for
a greater degree of time.

Abnormalities: Limb Reduction Anomalies

I'm gonna start this talk of abnormalities
with limb reduction anomalies
and let's go with abnormal number.
As you all know, there can be too many or too few digits
or absolutely complete absence of the digits
or even the entire hand and foot.

Polydactyly

One of the most common anomalies we see is polydactyly
and that is an extra digit on the hand or foot.
It can be completely soft tissue
or it can have osseous structures.
It's important to identify the location
of the extra digits post axial occurring laterally on the
ulnar or fibular side and pre axial medially
or on the radial side.
It's also always really critical to review family history
as a lot of these conditions can occur in families.

Here we see the most common type of extra digits
and that is post axial polydactyly.
This patient was referred for possible renal agenesis
and there's an extra digit on both the left foot
and on the left hand.
Notice that the extra digit on the left hand is flexed
and a little bit more difficult to see.

This is the clip in the exact same patient
and we can see that the extra digit actually has two tiny
little phalanges in it.
It's really important for orthopedic surgeons in planning for removal of these extra digits to know whether there is soft tissue only or soft tissue
and bony structures.

This is a very unusual case of eight toes, but
otherwise normal digits.
The parents wanted to continue this pregnancy.
Here we can see that there is club with a club foot deformity,
which we will talk about a little later.
And at birth there was a leg length discrepancy in hip dysplasia.
The orthopedics were able
to easily remove the three extra digits and cast the foot,
and the parents were very happy with the ultimate outcome.

Pre axial polydactyly is a lot
less common than post axial polydactyly.
Here in this case we can see that there was bilateral clubfoot
and a total of seven toes notice
that the extra digit was bifid and in addition, there was kyphoscoliosis absent fibula
and ventricular hypertrophy.
This was a 40-year-old mom who had been trying to conceive
and basically the diagnosis was made relatively
late in pregnancy.

Oligodactyly

What does oligodactyly look like?
It's much less common than polydactyly and so
whenever you see abnormal digits, it's important
to assess all of the long bones.

Here is a case of twins where twin B has only three
toes or three metatarsals on the left extremity.
Note the markedly bowed right femur
and there's also, if you notice,
the right lower leg has a tibia that's very,
very shortened and there was abnormalities
and malformation of the fibula on both sides.

Acheiria and Apodia

Let's talk about terms as acheiria is a term that refers
to complete absence of the hand.
And as you can see here on this 3D, there's no bone
or soft tissue beyond the distal lower extremity.
Notice the difference in the measurements
of the bones on the normal left extremity compared
with the right upper extremity.
And notice the shortening that we see here.

When we turn on color doppler for comparison, we can see
that there is a significant difference in blood flow
with a small right singular ulnar artery
and compared to the normal radial and ulnar artery.
On the left side, a apodia is a condition that refers
to complete absence of the foot.
This was a case of limb regression syndrome
that had a very shortened and abnormal sacrum,
but notice there's only one bone in the distal lower extremity
and there is no foot and no osseous structures.
To suggest a foot below the level of the ankle.

We are gonna move from number of digits,
both polydactyly and oligodactyly to abnormal size of digits.
There are various terms that you see here that refer
to the abnormal size or length of the digits.
They can be large or small, short long
and there's one measurement that we have
for digits currently and that is mainly the foot length
and you can compare the foot length to the femur length when you suspect possible intrauterine growth restriction.
And the normal femur
to foot length ratio is usually about 1.0, so they're equal
as a constant from about 14 weeks
until the end of gestation.

Abnormal Size Examples

Here's an example of enlarged digits.
Notice that the thumb,
the first digit
and the great toe was enlarged on both of the hands.
In this case of proven Ellis Van Creveld syndrome,
we can see these very large digits
and in addition, there were extra digits on both hands.

Here's an example of a Trident hand.
This is a proven case of thanatophoric dysplasia
and this fetus had severe micromelia
with all of the long bones.
Seven to eight weeks delayed.
We can see the telephone receiver femur
with the marked curvature
and we can see the bell-shaped thorax.
The thoracic circumference was less than the two point fifth
percentile and we can see
how the abdomen looks bulging compared
to the very small AP diameter of the chest.

Here we have the Trident hand appearance with all
of the digits of equal length
and the foot length was short compared to the nomograms.
For this expected gestational age.
The parents in this case chose to terminate.

Here's another case of severe micromelic skeletal dysplasia
and this refers to brachydactyly where all
of the digits are very short
and you can see the right hand displays a very short digits.

Here's a view of the corresponding left
hand and the left thumb.
In rare cases we will do low dose fetal ct
and this corresponds to the ultrasound findings.
Notice that all of the digits
are very short on both the hands and feet.

This was an unusual case
where we couldn't get any agreement on the final diagnosis.
And whenever that happens, we send our very difficult cases
to the International skeletal society
and they could not agree on the
ultimate diagnosis in this case.
And again, the parents elected to terminate the pregnancy.

Alignment Abnormalities

Let's move to alignment abnormalities.
This can involve both the hands and the feet
and you can see the corresponding terms
that we have listed here.
And I'm going to show you examples of
what these conditions look like.

Clubfoot Deformity

Starting with the most common alignment abnormality,
which is the clubfoot deformity or talipes.
And there are many types of talipes,
but the most common is gonna be talipes equinovarus
where there's plantar flexed foot
and there's medial deviation.
So what happens is in the coronal view, you are able
to see the foot
and the leg in the same plane, which is
what you don't want to do.
Clubfoot is bilateral in approximately two thirds of cases.
There's often a positive family history,
but it also can be a marker for various anomalies
and different syndromes.
We also use 3D at our institution as a way
of avoiding possible false positive
or false negative findings.

Here in this case we can see that there's bilateral talipes.
One of the tip offs is
that the feet can often be crossed at the ankles
for a significant part of the examination.
Notice the muscle thinning in a case
of proven muscle atrophy.
And again, the legs were persistently crossed throughout this examination,
which is an unusual and atypical finding.

Club Hand

Let's move to club hand.
Club hand is a lot less common than clubfoot
and the most common abnormality you will see will be the
radial ray malformation,
which occurs much more frequently than an ulnar club hand.
In radial ray malformation, there's usually an absent
or hypoplastic radius
and the hand is deviated variably the thumb can appear
either absent or hypoplastic or be abnormally angled.
The radial club hand is frequently associated with syndromes,
whereas the ulnar club hand is usually isolated.
So let's look at examples.

Here we can see
that there is severe fixed flexion at the level
of the wrist joint.
Here we see that here. These are the digits of the hand.
Here's the ulnar and the radius area.
This is the humerus and the elbow.
And notice that there is no change in the appearance of the wrist or of the digits of this right hand.
And in addition, the thumb was absent.

This is an example of ulnar club hand.
It is a very, very rare condition.
I've seen very few cases in my many years of work.
Here we can see that there is severe ulnar hypoplasia.
Notice that the bone is not as mineralized
as the adjacent radius.
It is also discontinuous
and if you look very closely at the hand,
there is a proximal phalanx and a distal phalanx
but no third middle phalanx.

This was a really unusual case that was subsequently proven
by our geneticist to represent Roberts syndrome.
This is that same fetus.
You can see the hand moving
and notice again that there is a proximal phalanx
and a distal phalanx,
but just soft tissue in the middle
without the middle phalanx.

This is that same fetus. Here's the face.
We can see that there is micrognathia.
There was also a cleft palate
and notice that the nasal bridge is abnormally flattened.

Rocker Bottom Foot

Let's move on now to rocker bottom foot.
This is different from a club foot.
It has a rounded configuration on the bottom of the foot
or the plantar surface.
It is important to notice this condition
because there's a strong association with trisomy 18.
It can be seen in association with clubfoot deformity
and it's rarely isolated.
And all of these are a list of conditions where you can actually see rocker bottom foot deformity.

Here's an example of a unilateral rocker
bottom foot notice the rounding curvature
and the fatness of the heel.
This was in a case of myelomeningocele
and we can see the large myelomeningocele sac there distally
involving the lumbosacral spine.

Sandal Gap Foot

Sandal gap foot is a specific term that refers
to an increased space between the first and second digits.
The great toe is usually abducted
and it is a marker for trisomy 21.
It can be associated
with either rocker bottom foot deformity
or club foot deformity or it can be isolated.

Here's an example of a sandal gap deformity.
Notice a wide space between the first digit,
the great toe and the second toe.
This fetus also had a thickened nuchal fold
that measured eight millimeters and absent nasal bone.
This was a proven case of Trisomy 21.

Here is another case of bilateral sandal gap deformity.
Notice the large great toe, the big gap between the first
and the second digits.
This fetus had mild renal ectasia
and you can see that the pelviectasis are both over four
millimeters and a cleft lip and palate.
However, this was proven not to represent Trisomy 21.

Clinodactyly

Clinodactyly is a term that refers
to fixed inward curvature of a finger.
It's usually associated with asymmetric hypoplasia
of the middle phalanx.
It most often involves the fifth digit of the hands
and it can be associated with a number of trisomies,
but it's known to be a common marker of Trisomy 21.

Here's an example of multiple different patients
who have clinodactyly.
Notice that the middle phalanx is small
in every single case.
This was an unusual case
where we actually showed the soft tissue palmar crease.
Again, proven cases of Trisomy 21.

Camptodactyly

Camptodactyly refers to a flexion contracture
of the proximal interphalangeal joint.
This is again a fixed deformity.
It can involve multiple digits
and be associated with various trisomies.
As we see here, it is often asymmetric
and it can be isolated.

There's an example in this proven case of Trisomy 21
of camptodactyly, which was bilateral.
Notice that the digits are flexed
and they are persistently flexed.

Here on the 3D rendering we can see the third
and fourth on both hands are persistently together
and fixed flexion in a proven case of camptodactyly.

Syndactyly

Let's move to syndactyly.
This refers to fusion of the digits
and there are four distinct types of syndactyly.
Complete means it affects the entire length of the digit.
Partial is generally the proximal segment of the digits
and syndactyly can be associated with additional digits
as well and fusion of the joints.
So let's look at some examples.

Here is a spinning clip that shows syndactyly of the second
and third digits of the right foot.
Here on this fixed image you can see
how these two digits stay together,
whereas we can see amniotic fluid that intervenes
between the first digit and the second digit.

This is a 3D rendering, again showing syndactyly,
which is the most common type complete
that involves the entire length of the digit.
This is that same patient that had a proven diagnosis
of CHARGE syndrome.
Here we can see the VSD that was associated with tetralogy of Fallot.
There were malformed low set ears,
micrognathia on this 3D image exophthalmos
with a bulging globe.
And notice that there is a double bubble sign.
This was actually duodenal stenosis, not atresia.
We can see the stomach, the proximal duodenum
or the duodenal bulb,
but notice that there is fluid distally in small bowel loops
that are adjacent to the bladder in the lower
abdomen and pelvis.

Here's an example of complete syndactyly.
This was a proven case of Pierre Robin syndrome.
Notice a severe retrognathia, there is no thumb.
And we can see how
the hand looks like a mitten on this right
hand compared to the normal left hand
that has individual digits
that we can distinctively identify.
Incidentally, in this case there was also a apodia.
A total absence of the left foot.

Incomplete syndactyly again refers to proximal fusion.
Notice how as this fetus moves this hand
that the digits are together proximally,
but there's clear fluid insinuated
between the distal aspects of the digits.

We can see those findings here on the 3D examination.
And on the 2D examination with the extended fingers,
this was a proven case of Mosaic Trisomy 17 where some
of the chromosomes had the trisomy 17 and others did not.

Here is a proven case of polysyndactyly.
It's very unusual.
Notice that there is partial duplication of the left foot
so we can see extra digits
and not only are there extra digits,
but the digits are fused.
So you can never separate the metatarsals
and phalanges in this foot
because they all move together as a single unit compared
to the contralateral normal.
Right foot.

Ectrodactyly

Ectrodactyly is a specific
deformity that has been called the lobster claw deformity.
There is a huge deficiency within the central digits
where there is absence soft tissue.
And this can be an isolated deformity,
it can be associated with a facial cleft.
It can also occur as a new dominant mutation
and it can be familial
and it has been shown to be inherited in various families.

Here's an example of what it looks like.
Notice that there is a large soft tissue cleft
between the digits here on the 3D rendering.
And on 2D we can see this large soft tissue cleft
that is referred to as lobster claw deformity
with the technical name of ectrodactyly.
That was a case involving both hands.

Here is a case involving both feet
and interestingly here is a case involving both
feet and both hands.
So the 3D shows a large soft tissue cleft involving all
four extremities.

Limb Reduction Abnormalities

I'm going to end up with limb reduction abnormality
and here is a long list of the different abnormalities
that can occur under this classification.
They are often associated with hand and foot anomalies,
but in the interest of time we're gonna only
cover a few examples.

Amniotic Band Syndrome

So let's start with amniotic band syndrome.
This is when there's been a disruption of the amnion,
which actually entraps various fetal parts.
It most commonly involves the extremities,
especially the fingers and toes.
It's important to look for free floating bands within the amniotic fluid
and to look at various body parts
to see if we can tell exactly which digits
or which extremities are involved.
At our institution we will go in
and lyse the bands in some cases,
however, this was a case where the band is so deeply
embedded in the soft tissues that there is resultant edema.
You can see the fetal edema involving the right foot there
and notice that there is actually deformity in the bone,
which is rare due to the fact
that this was a severely tight amniotic band
that we were not able to lyse.

Here's a more recent case that I just had last week.
This patient was referred for holoprosencephaly.
You can understand what the physicians were probably thinking.
Notice this abnormal profile is very unusual.
There was a large facial cleft involving both the lip and the palate.
Here you see it measures over a centimeter,
but notice the deformity of the calvarium.
The bones are actually absent from the parietal frontal region on both sides greater on the left than on the right.
Notice the deformity of the calvarium, again,
the dilation of the ventricles.
Here we can see the left ventricle measured
over two centimeters.

This is that same patient.
And at the end of the examination we were able to actually increase the gain
and go to the left upper portion of the uterus.
In this fundus was where the fetal head seemed
to remain even though some
of the lower body parts were moving.
Interestingly, there were no anomalies of the hands
and feet, but we can see here the bands
that are clearly attached to the region of the fetal face
and the calvarium.
And it was difficult
to separate these linear bands from the umbilical cord,
which was also situated in the left upper fundus of the uterus.

Arthrogryposis

I'm going to end with arthrogryposis,
which is a very unusual fetal akinesia deformation sequence.
And what this refers to is multiple joint contractures
that involve two or more areas of the fetus.
There's virtually a lack of extremity motion
with abnormal extremity posturing.
It can be associated with club feet and club hands
and the fetus often doesn't swallow normally.
So there can be polyhydramnios,
which actually allows us better visualization
of the extremities, particularly if the pregnancy is later.

And here we can see this patient was diagnosed late
and we can see the abnormal posturing
with the lower extremities.
Actually at the back of the fetal calvarium we can see the marked scoliosis of the spine.
As the fetus turns backwards.
Notice the narrowing of the soft tissues related
to the posturing deformity
that involved both the hands and the feet.

This child was born and had a neonatal death.
And at autopsy our pathologist believed
that this whole incident probably started with congenital dislocation of both hips.
But notice after birth we can see
that the abnormal posturing of both the upper extremities
and the hands as well as the lower extremities
and the feet clearly simulate the ultrasound examination.

Exactly. I thought I'd never ever see a case of this again.
And here is my second case.
Notice the abnormal posturing again
of the feet in lower extremities posterior to the hands.
And this is a different appearance
where there was fixed flexion at the wrist, which is distinctly different from the case I just showed you.

Conclusion

In conclusion, I think that suspicion of a hand
or foot anomaly clearly warrants a very thorough examination
of the extremities.
Some of these anomalies may be isolated,
but others can suggest a very specific diagnosis,
which is really important for patient counseling
and pregnancy management.
We wanna make sure that the parents are aware of all
of the findings that we can see.
We want to do extensive genetic counseling
because they often have a fear that whatever the anomaly is
that could possibly affect a subsequent pregnancy.

And I would like to leave you with this fetal version
of the Vulcan Salute by Mr.
Spock from the Star Trek movies,
just in case any of you are Trek fans.
Thank you for your attention.