test 4 Flashcards
1
Q
what are the 2 tissues that skeleton is composed of?
A
- bone
- cartilage
2
Q
what are the cell types of the skeleton?
A
- osteoblasts
- osteoclasts
- chrondrocytes
3
Q
what are the 3 embryonic cell linages?
A
- cranial neural crest cells
- paraxial mesoderm cells or somites
- lateral plate mesoderm
4
Q
what is formed from the cranial nural crest cells?
A
craniofacial skeleton
5
Q
what is formed from the paraxial mesoderm cells or somites?
A
axial skeleton
6
Q
what is formed from the lateral plate mesoderm?
A
responsible for limb formation
7
Q
when do limb buds begin to develop?
A
during the 4th week of embryonic life (th mentral week)
8
Q
do the upper limbs or lower limbs form first?
A
upper limbs do (bud appearance, develpment, differentiation and establishment of final relative limb size)
9
Q
what is the order of development of the fetal limbs?
A
- humerus and femur
- radius, ulna, tibia, and fibula
- metacarpal and metatarsal bones
- phalanges
10
Q
what are the 4 steps of skeltognesis?
A
- patterning
- organogenesis
- growth
- homeostasis
11
Q
what is patterning?
A
final size, shape, number and arrangment of bones are determined
12
Q
what is organogenesis?
A
bone and cartillage are formed
13
Q
what is homeostasis?
A
the tendency of the body to seek and maintain a condition of balance or equilibrium within its internal environment, even when faced with external changes
14
Q
where are the long bones measured?
A
between the distal and proximal ossification centers
15
Q
what should the cardio-thoracic circumference be less than throughtout gestation?
A
slowly increases through gestation but should always be less than 0.5
16
Q
why may cardio-thoracic circumferance be increased?
A
cardiac=fetal cardiomegaly
thoracic=pulmonary hypoplasia
17
Q
what is the thoracic/abdominal circumferance after 20 weeks?
A
> 0.8
18
Q
what are the indications for careful survey of the fetal skeleton?
A
- fam history with a known genetic risk
- detection of a fetal anomaly during a routine OB study
19
Q
what is skeletal dysplasia?
A
medical term for what most people refer to as “dwarfism” It is am umbrealla term for a group of hundreds of conditions affecting bone and cartilage growth
20
Q
a child born with skeletal dysplasia will have an abnormal difference in what?
A
shape of:
- legs
- arms
- trunk
- skull
21
Q
how is classification of skeletal dysplasia made?
A
underlyinh molecular abnormalities
22
Q
what is prenatal sonographic diagnosis of skeletal dysplasia centered on?
A
combinations of abnormal finding of the limbs, rib cage, skull, and spine
23
Q
what is the most common severe skeletal dysplasia manifest with?
A
- severe micromelia (shortening of all limbs)
- variabel degrees of thoracic dysplasia
24
Q
what is the most common way skeletal dysplasia is detected?
A
measurment of FL
25
what does it mean when FL is 1-4 mm below 2 SD point?
further serial measurments are required to determine if a skeletal dysplasia is present
26
what does it mean when FL is 5mm below the 2 SD point?
there is a high liklihood of skeletal dysplsia
27
what is used to determine skeletal dysplasia versus severe IUGR?
femur length to feet length ratio
28
what does the femur length and foot length ratio tell us with sever IUGR?
femur length is abnormally small however the femur length to foot length ratio remains essentially normal
29
what does the femur length and foot length ratio tell us with skeletal dysplasia?
the femur length to foot length ratio decreases, since foot length is unaffected and the femur is shortened to different angles
30
what are the 4 patterns of shortnening of the long bones?
- rhizomelia
- mesomelia
- acromelia
- micromelia
31
what is rizomelia?
shortening of proximal segment (femur, humerus)
32
what is mesomelia?
shortnening of middle segment (radius, ulna, tibia, fibula)
33
what is acromelia?
shortnening of distal segment (hands and feet)
34
what is micromelia?
shortnening of entire limb (mild, mild/bowed, severe)
35
with skeletal dysplasia, severe ________ are lethal
micromelia
36
what is thoracic dysplasia associated with?
abnormally snall misshapen chest and is associated with pulmonary hyperplasia
37
what is frontal bossing?
the development of an unusually pronounced forehead which may also be associated with a heavier than normal brow ridge
38
what causes frontal bossing?
enlargement of frontal bone
39
what is the most common LETHAL skeletal dysplasia?
thanatophoric dysplasia
40
what is the most common NONLETHAL skeletal dysplasia?
achondroplasia
41
what are the prevalance of disorders of muscoskeletal?
- Thanatophoric dysplasia
- Achondrogenesis
- Osteogenesis imperfecta
- Achondroplasia
42
what disroders are caused by different lutations in the fibroblast growth factor receptor 3 gene?
- Achondroplasia
- Hypochondroplasia
- Thanatophoric dwarfism
43
achondroplasia is autosomal ___________
dominant
44
what is associated with achondroplasia?
- Rhizomelic shortening
- mild limb bowing
- exaggerated lumbar lordosis
- enlarged head
- bones of hand and feet are short (trident hand)
- frontal bossing
- mid face hypoplasia
- flattened nasal bridge
- broad mandible
45
what is homozygous achondroplasia?
early shortnening of femurs
| -letal in first 2 years of life
46
what is associated with heterozygous achondroplasia?
- short fingers and toes
- large head with prominent forehead
- small midface with a flattened nasal bridge
- spinal kyphosis or lordosis
- varus ir valgus
- ear infections
- sleep apnea
- hydrocephalus
47
what is spinal kyphosis?
convex curvature
48
what is spinal lordosis?
concave curvature
49
what is varvus?
bow leg
50
what is valgus?
knock knee
51
why does macrocephaly occur?
large head associated with hydrocephalus due to obstruction at the level of the foramen magnum
52
at what gestatinal age might the shortened limbs be detected?
varies between 21-27 weeks
53
hypochondroplasia is autosomal __________
dominant
54
what does hypochondroplasia resemble?
achondroplasia but features are milder
- sparing of the head
- lack of tibial bowing
55
what is Thanatophoric dwarfism characterized by?
- Extremely short limbs
- Folds of extra (redundant) skin on the arms and legs
- Narrow chest
- Short ribs
- Underdeveloped lungs
- Enlarged head with a large forehead
- Prominent, wide-spaced eyes.
56
what is type 1 of Thanatophoric dwarfism?
thanatophoric dysplasia is distinguished by the presence of curved thigh bones and flattened bones of the spine (platyspondyly)
57
what is type 2 of Thanatophoric dwarfism?
straight thigh bones and a moderate to severe skull abnormality called a cloverleaf skull
58
do most infants with Thanatophoric dwarfism survive?
no
59
what is associated with Thanatophoric Dysplasia?
- severe micromelia
- severe thoracic dysplasia
- polyhydramnois
- cloverleaf skull deformity
60
what are additional findings of Thanatophoric Dysplasia?
- Ventriculomegaly
- Macrocranium
- Cerebellar hypoplasia
- Prominent forehead
- Saddle nose
- Hypertetorism
- Short ribs
- Platyspondyly
61
what is Platyspondyly?
a radiographic feature and refers to flattened vertebral bodies throughout the axial skeleton
62
what is the most common spinal abnormality?
skelteal dysplasia
63
what does Thanatophoric Dysplasia look like?
significant narrowing of the chest and prominent abdomen
- shortened bowed limbs
- narrow thorax with short ribs
- large head
64
what is the 2nd most common lethal skeltal dysplasia?
achondrogenesis
65
what has the most severe degree of limb shortnening?
achondrogenesis
66
how is achondrogenesis type 1 characterized?
- inadequate ossification of the skull, spine, and pelvis
- extensive shortnening of tubular bones
- multiple rib fractures
67
how is achondrogenesis type 2 characteried?
- various degrees of calcification of the pelvis, skull, and spine
- without rib fractures
- most type 2 cases are sporadic (new autosomal dominant mutations)
68
which achondrogenesis is autosomial dominant and whic is recessive?
recessive=type 1
| dominant=type 2
69
what are the sonographic features of Achondrogenesis?
- short femur length (below 5th percentile)
- trident hand and 4 fingers appearing separated and similar in length
- protruding forehead (frontal bossing)
70
what is taken as a useful measurement for Achondrogenesis?
femur length (FL) to biparietal diameter (BPD)
71
what is Hypophosphatasia?
an inherited disorder that affects the development of bones and teeth (disupts mineralization)
72
what are infants affected with Hypophosphatasia born with?
- short limbs
- abnormally shaped chest
- soft skull bones
73
with Hypophosphatasia the spine is usually ______________
hypomineralized
74
what are the 2 conditions most commonly associated with hypomineralization of the spine?
achondrogenesis type 1
| hypophosphatasia
75
what is not affected with achondrogensis type 1?
skull
76
what does hypomineralized look like?
less echogenic than normal and attenuation of the vertebrae and enhanced visualiation of the spinal cord
77
what is osteogenesis imperfecta?
a congenital bone disorder characterized by brittle bones that are prone to fracture
78
what is associated with osteogenesis imperfecta type 1?
- blue sclera
- hyper laxity of ligaments and skin
- hearing impairment
- no prenatal deformities
79
what is associated with osteogenesis imperfecta type 2?
- lethal
- no ossification of the skull
- beaded ribs
- shortnened and crumpled long bones
- multiple fractures
- throaxis short but not narow
80
what is the most common anomaly associated with fetal fractures?
Osteogenesis imperfecta
81
what is caudal regression syndrome?
a disorder that impairs the development of the lower (caudal) half of the body
82
what are the affected areas with caudal regression syndrome?
lower back and limbs
genitourinary tract
gastrointestinal tract
83
what happens with the spinal system with caudal regression syndrome?
the bones of the lower spine (vertebrae) are frequently misshapen or missing and the corresponding sections of the spinal cord are irregular or missing
-may have scoliosis
84
what are the abnormalties associated with caudal regression syndrome?
- spine
- affect size and shape of chest making it hard to breathe
- small hip bones
- undeveloped bones in legs
- frog like postion
- inward and upward turning feet (clubfeet) or calcaneovagus
85
what are genital abnormalities in males with caudal regression?
- urethra opening on the underside of the penis (hypospadia)
| - cryptorchidism
86
what are the genital abnormalities in females with caudal regression?
an abnormal connection between the rectum and vagina (rectovaginal fistula)
87
what are the malformations of the GI tract in caudal regression?
- abnormal twisting (malrotation) of the large intestine
- obstruction of the anal opening (imperforate anus)
- soft out pouchings in the lower abdomen (inguinal hernias)
88
what are defects with the kidney in caudal regression?
- unilateral renal agenesis
- horseshoe kidney
- ureteral duplication
89
what is sirenomelia also known as?
mermaid syndrome
90
what is sirenomelia?
very rare congenital deformity in which the legs are fused together, giving them the appearance of a mermaids tail
91
do infants usually survive with sirenomelia?
usually fatal with a day or two due to complications with abnormal kidney and urinary bladder development and function
92
how does sirenomelia usually result?
failure of normal vascular supply from the lower aorta in utero
93
what is amniotic band syndrome?
group of congenital birth defects believed to be caused by entrapment of fetal parts in fibrous amniotic bands while in utero
94
what is the exogenous theory for amniotic band syndrome?
an early disruption of the amnion allows the embryo or fetus to enter the chorionic cavity and contact the chorionic side of the amnion leading to fibroud bands, which entrap the fetal body components
95
what is the endogenous theory for amniotic band syndrome?
occurs as a result of vascular compromise, mesoblastic strings are not a casual agent
96
what are detectable anomalies of the hand?
- absent hand
- absent digits
- extra digits
- unusual curvature of the digits
- abnormal flexion of the hand
97
what is radial ray anomaly?
compromise of a large spectum of upper limb anomalies which range from partial (radial hypoplasia) to a complete (radial aplasia) deficiency of the radius with or without accompanying deficiency of the the thumb bones
98
what is polydactyly?
refers to hand or foot with more than 5 digits
99
what is polydactyly most commonly associated with?
tri-13 and meckel-gruber syndrome
100
what is clinodactyly?
inward curvature of the 5th digit of the hand and is due to hypoplsia or the mid phalanx of the 5th digit
101
what is clinodactyly associated with?
tri-21 (61%)
102
what is a common finding with Tri-18?
persistently clenched hand with overlapping fingers
103
what is a clenched hand associated with?
- trisomy 18
- trisomy 13
- pena-shokeir syndrome
- smith-lemli-opitz syndrome
104
what is pena-shokeir syndrome?
autosomal recessive non aneuploidic condition with some clinical features being similar to that of trisomy 18. not often lethal
105
what is smith-lemli-opitz syndrome?
a lack of cholesteral production as well as build up a potentially toxic by products of cholesterol production which accumulate in the blood and other tissues
106
what is a trident hand?
the hands are short with stubby fingers, with a seperation between the middle and ring fingers
107
what is trident hand associated with?
various chondrodysplasias including achondroplasia
108
what is syndactyly?
refers to a congenital fusion of 2 or more digits
109
what fingers does triploidy tent to affect?
3rd and 4th digits of the hands
110
what are detectable abnormalities of the foot?
- absent foot
- absent toes
- extra toes
- club foot
- rockerbottom foot
- sandal foot
111
what is the sonographic diagnosis of club foot?
when the plantar profile of the foot is seen in the same image that shows the long axis of the tibia and fibula
112
what is club foot?
inverted, plantar-flexed, medially deviated foot results in the visualization of the long axis of the foot and tibia/fibula in the same plane
113
what is rocker-bottom?
abnormal curvature of the pedal arch, it appears as a conves curvature (most commonly associated with Tri-18)
114
what is sandle foot?
an apparent increase in the space between the great toe of the foot from the rest of the toes
115
what is sandle foot associated with?
down syndrome
116
fetal ascities is diagnosed when fluid is seen where?
- between bowel loops
- along the abdominal flanks
- around the liver
- outlining the abdominal visera
117
what is solated ascites caused by?
obstructive urinary or gastrointestinal obstruction
118
what does amniotic fluid outline in advanced ascites?
- liver
- spleen
- small bowel
- umbilical vein
- falcifirm ligament
119
what is pseudoascites?
small hyperechoic band (<2cm in thickness) extending along the anterior and lateral fetal abdomen
120
what is a key feature in pseudoascites and ascites?
pseudoascites does not surround the liver and is always a subcutaeous finding whereas the true ascites will extend around bowel loops
121
what is hydrops fetalis?
rhesus (Rh) blood group isoummunization of the fetus
122
what are the hydrops fetalis symptoms?
- placental thickening
- abdnormal fluid in the abdominal cavity, heart, and lungs
- general edema
- excess amniotic fluid
123
what does fetal hydrops refer to?
pathological accumulation of fluid in 2 or more body cavities of tissue
124
what is associated with fetal hemolytic disease?
- anemia
- extramedullary erythopoiesis
- hepatosplenomegaly
- hypoalbuminemia
- congestive heart failure
125
how is immune hydrops prevented?
300mg of RhoGam is given at 28 weeks gestation in sensitized individuals or within 48h invasive fetal procedure
126
what are the causes and associations with maternal non-immune hydrops?
- uncontrolled diabetis
- severe anemia
- severe hypoproteinemia
- indomethacin
- prematire closure of ductus arteriosus
- maternal syphilis
- maternal hyperthyroidism
- cytomegalovirus
- parvovirus B19 (5th diseae)
127
what are the causes and associations with placenta/cord non-immune hydrops?
- large chorioangioma
- umbilical artery aneurysm
- cord torsion, knot, or tumor
128
what is indomethacin (indocin)?
prescription drug used to treat moderate to severe pain, swelling, and stiffness from arthritis (not good during pregnancy)
129
what can syphilis cause in pregnant women?
miscarriage, stillbirth, or the baby's death shortly after birth
130
babies born with congenital syphillis can have what?
- bone damage
- severe anemia
- enlarged liver and spleen
- jaundice
- nerve problems causing blindness or deafness
- meningitis,
- skin rashes
131
what condtion is characterized by decreased fetal movement?
fetal akinesia deformation sequence (FADS)
132
what may FADS be caused by?
mutations in the RAPS or DOK7 genes
133
what is gestational age determined by?
- LMP
- Mean gestational sac
- crown rump length
- BPD, HC, AC, FL
134
SGA babies usually have birth weights below ________
10th percentile
135
how may babies with SGA appear?
proportionally small or they may b of normal length and size but have lower weight and body mass
136
how is intrauterine growth restriction (IUGR) defined?
fetus that is underachievieng its growth potential becuase the fetus does not recieve the necessary nutrients and oxygen needed for proper growth and developement
137
what is early-onset IUGR often due to?
- chromosomal abnormalities
- maternal disease
- severe problems with the placenta
138
what is late-onset IUGR related to?
after 32 weeks is usually related to other problems
139
what are the maternal factors for SGA?
- High blood pressure
- Chronic kidney disease
- Advanced diabetes
- Heart or respiratory disease
- Malnutrition, anemia
- Infection
- Substance use (alcohol, drugs)
- Cigarette smoking
140
what are the factors involving the uterus and placenta for SGA?
- Decreased blood flow in the uterus and placenta
- Placental abruption (placenta detaches from the uterus)
- Placenta previa (placenta attaches low in the uterus)
- Infection in the tissues around the fetus
141
what are factors for SGA related to the devloping fetus?
- multiple gestation
- infection
- birth defects
- chromosomal abnormality
142
why is SGA/IUGR a concern?
When the fetus does not receive enough oxygen or nutrients during pregnancy, overall body and organ growth is limited, and tissue and organ cells may not grow as large or as numerous.
143
what may babies with SGA or IUGR have problems with at birth?
- decreased oxygen levels
- low Apgar scores
- meconium aspiration
- hypoglycemia
- difficulty maintaing normal body temperature
- polycythemia
144
when is IUGR considered?
when baby is lower tha 10th percentile of the gestatonal age curve
145
what causes IUGR?
placental insufficiency, either primary or secondary to a maternal etiology
146
symmetric SGA
ALL measurements (HC, length weight) are reduced
147
Asymmetric SGA
only have a weight reduction
148
what is symmetric SGA's usually caused by?
due to causes that occur at early stages of pregnancy
149
what is asymmetric SGA's caused by?
insults that appear in the 3rd trimester
150
symmetric IUGR has ___________ reduction in all fetal parameters
proportional
151
what is symmetruc IUGR associated with?
chromosome anomalies (most common)or infection (2nd most common)
152
what is the sonographic diagnosis of symmetric IUGR?
-Early onset should be considered in the 1st trimester if there is a CRL - good menstrual dates discrepancy greater than one week.
153
what does asymmetric IUGR result from?
placental insuffciency
154
what does asymmetric IUGR result from?
preferntial blood flow to the fetal brain
155
what is elevated in fetuses with asymmetric IUGR?
FL/AC ratio
| HC/AC ratio
156
what are non-specific findings of IUGR?
- oligohydramnois
- placental senescence
- Grade 3 (calcification)
- delayed sonographic appearance of the distal femoral ossification center
157
when is macrosomia or larger for GA fetus mean?
weight above the 90th percentile
| fetal weight > 4000g
158
what is the most common risk factor for macrosomia?
maternal diabetes
159
what do the ratios means for macrosomia?
FL/AC and HC/AC ratios are low
160
what is the normal chromosomal number?
46
161
what is aneuploidy?
any deviation from the diploid number of 46 chromosomes
162
what are the most common aneuploidies?
- Trisomy 21 (Down’s Syndrome)
- Trisomy 18 (Edward’s Syndrome)
- Trisomy 13 (Patau’s Syndrome)
- Turner’s Syndrome (45, XO)
163
what is the highest risk for chromosomal abnormalities?
- advanced maternal age
| - previously affected child
164
what lab results show risk of aneuploidy?
low maternal serum alpha-fetaprotein and abnormal maternal serum triple-screen-patterns
165
what is the most common chromosomal abnormality?
trisomy 21
166
what is shown is trisomy 21?
- mild ventriculomegaly (10-12mm)
| - nuchal thickening
167
what is needed to be seen in the nuchal thickening scan?
oblique plane showing CSP anteriorly and cisterna magna posteriorly (6mm or greater at 15-20 weeks=abnormal)
168
what is the most common cardiac anomaly associated with trisomy 21?
atrioventricular canal defect (endocardial cushion defect)
| -Echogenic intracardia foci as an isolated finding
169
what is shown in trisomy 21?
- cardiac anomaly
- duodenal atresia
- echogenic bowel
- mild pyelectasis
- widened iliac angle (60-75 degrees)
- shortening of the femur and humerus
- clinodactyly of the 5th digit
- sandal gap toes
170
what is shown in trisomy 18?
- IUGR
- Strawberry shaped head
- choriod plexus
- enlarged cisterna magna
- cardiac anomalies
- congenital diaphragmatic hernia
- omphalocele
- perisstent clenched hand with overlapping digits
- club foot
- rocker bottom feet
171
what is shown in trisomy 13?
- IUGR
- microcephaly
- holoprosencephaly
- facial defects
- cardiac anomalies (ventricular deptal defect)
- genitourinary anomalies
- polydactyly
172
what facial defects are associated with trisomy 13?
- cleft lip
- ocular abnormalities (hypotelorism)
- nose abnormalities (absence of nose)
173
what is the most common genitourinary anomalies?
cystic renal dysplasia
174
who is turners syndrome only affected in?
females (one of the X chromosomes missing)
175
unlike trisomies, what is turners syndrome not associated with?
not associated with maternal age
176
what is shown in turners syndrome?
- fetal hydrops
- cystic hygroma
- cardaic anomalies (coarctation)
177
which condition affects many areas of the body?
noonan syndrome
178
what is noonan syndrome characterized by?
- mildly unusual facial characteristics
- short stature
- heart defects
- bleeding problems
- skeletal malformations
179
in noonan syndrome about _______ have short stature
50-70%
180
what is the mostc common heart defect in noonan syndrome?
pulmoanry valve stenosis
181
what is noonan syndrome caused by?
genetic mutation
182
how does triploidy result?
from an extra haploid set of chromosomes at fertilization with the extra set of chromosomes usuing being paternal (ovum fertilized by 2 sperm)
183
what anomanies occur with triploidy?
- brain=alobar holoprosencephaly
- hands and feet=polydactlyly
- short femur=(60%)
- molar pregnancy=(prior 20 weeks gestation)
184
what is associated with the pentatolgy of cantrell?
- ectopia cordis
- heart defect
- diaphragmatic hernia
- pericardial defect
- omphalocele
185
what syndrome is classified as an overgrowth syndrome?
beckwith-weidemann syndrome
186
what is the usual growth pattern known as in beckwith-wiedemann syndrome?
hemihyperplasia
187
what are common signs and symptoms of beckwith-wiedemann syndrome?
- macrosomia
- macroglossia
- omphacele
- renal neoplasm
188
what are people with beckwith-wiedemann syndrome at increased risk of developing?
- wilms tumor
| - hepatoblastoma
189
what are the common fetures of meckel-gruber syndrome?
- enlarged kidneys with fluid filled cysts
- an occipital encephalocele (sac like protrusion of brain through opening in skull)
- presence of extra fingers and toes (polydactyly)
- scar tissue (fibrosis) in the liver
190
how do most individuals with meckel-gruber syndrome die from?
respiratory problems or kidney failure
191
what is walker warburg syndrome?
in inherited disorder that affects development of the muscles, brain, and eyes
192
what is the most severe of a group of genetic conditions known as?
congenital muscular dystrophies
193
how does walker warburg syndrome affect the brain?
cobblestone lissencephaly
194
how is smith lemli opitz syndrome characterized?
- distinctive facial features
- microcephaly
- intellectual disability or learning problems
- behavioral problems
195
what is fetal alcohol syndrome?
a pattern of mental and physical defects that can develop in a fetus in association with high levels of alcohol consumption during pregnancy
196
how does fetal alcohol syndrome affect baby?
alcohol crosses the placental barrier and can shunt fetal growth or weight, create distinctive facial stigmata, damage neurons and brain structures
