All of the following are true about somites except:
They begin to develop in the 6th week
They form the craniocaudal sequence for the embryo and are the origin of most of the axial skeleton and associated musculature
They develop from the paraxial mesoderm as the neural tube is forming
They differentiate into 2 parts, the sclerotome and dermomyotome
They appear as bead-like elevations along the dorsolateral surface of the embryo
Which of the following structures will eventually form vertebrae and ribs?
Notochord
Sclerotome
Dermomyotome
Meningotome
Which answer best describes the kind of bones developed through intramembranous ossification?
Femurs and Humerus
Rubs and Sternum
Flat bones of the Calvaria/Skullcap, Maxilla, Mandible
Malleus, Incus, Stapes, Hyoid
All of the following are considered to be lethal birth defects except:
Anecephaly
Bilateral renal agensis
Pierre Robin sequence
Thanatophoric dysplasia
All of the following are true regarding Rickets except:
It ca be due to vitamin D deficiency and hypophosphatemia
Affected individuals have short stature
Affected individuals have abnormal appearing bones/limbs aside from just short stature
Affected individuals rarely have other clinical manifestations
There are both recessive and X-linked forms
Which of the following ultrasound findings is not associated with renal agenesis?
Contractures
Brachycephaly
Anyhdramnios/Oligohydramnios
Absent blood flow to renal arteries
Which type of joint is capable of secreting protective fluid to cushion the surrounding bones?
Fibrous joint
Cartilaginous joint
Synovial joint
All of the following are part of the axial skeleton except:
Cranium
Vertebral column
Ribs
Clavicles
Sternum
In the 5th week the sclerotomes in the vertebral column have loosely arranged cells cranially and densely packed cells caudally. By the ___ week the vertebra are in the cartilaginous stage, arranging bone models and by the ___ week ossification beings. By ___ the bony halves are fused.
6th, 7th, 3-5 years of life
6th, 10th, the end of the 1st year of life
8th, 12th, birth
8th, 9th, 3-5 years of life
All of the following birth defects can be features of Down syndrome except:
Congenital heart defects
Pyelectasis
Macroglossia
Splayed cerebellum/banana sign
Congenital megacolon/Hirschsprung's
Which structure(s) describe where the cranial sutures meet and enable the bones of the skull to undergo shape changes during birth?
Fontanelles
Calvaria
Fibrous neurocranium
Hyaline cartilage
The increase in the size of the skull bones is greatest during which period?
Embryonic period
Fetal period
Birth-2 years
3 to 5 years
All of the following statements are true regarding sex determination except:
The female phenotype requires 2 X chromosomes
The male phenotype requires a functional Y chromosome
Ovarian and testicular development being around the same embryonic age
Hormones are required for male sex determination but not for female sex determination
Which of the following causes a long, wedge shaped cranium caused by early closer of the sagittal suture and is the most common type of idiopathic/isolated craniosynostosis?
Scaphocephaly
Plagiocephaly
Trignocephaly
The most common type of skeletal dysplasia is:
Camptomelic dysplasia
Chondrodypslasia punctata
Achondroplasia
Osteogenesis imperfecta
The myotome regions of the somites form _______ and the splanchnic mesoderm forms ______.
Limb muscles; head and neck muscles
Skeletal muscles; cardiac and smooth muscles
Head and neck muscles; skeletal muscles
Cardiac and smooth muscles; limb muscles
Which of the following is a risk factor for having a child with a skeletal dysplasia?
Advanced maternal age
Advanced paternal age
Maternal age <25 years old
Uncontrolled type 2 diabetes
The appearance and number of sites is used to determine embryonic age.
Intramembranous ossification occurs within a membranous sheath without prior cartilage formation.
Endochondral ossification occurs in preexisting bone models made from cartilage tissue.
Both the diaphyses (center bones) and epiphyses (ends of bone) remain cartilaginous throughout childhood/adolescence until bone growth is completed.
Prenatal detection methods can rarely detect forms of skeletal dysplasia.
Hyaline cartilage is the most widely distributed throughout the body (ie joints).
Joints develop from condensed mesenchyme and by 8 weeks resemble adult joints.
Short long bones identified on ultrasound can be a marker for skeletal dysplasia as well as for Down syndrome.
The FGFR3 gene is implicated in craniosynostosis syndromes but not skeletal dysplasias.
Accessory ribs, absence and/or variation of muscles, and unilateral multicycstic dysplastic kidneys are early common findings and usually of no clinical significance.
The micro deletion in DiGeorge/Velocardiofacial syndrome is
A potential cause of arthrogryoposis/joint contractors is ; ;
Describe 3 clinical features of CHARGE syndrome: ; ; ; ; ;
Describe 3 clinical features of VACTERL association: ; ; ; ; ; ;
is a condition characterized by absence of the pectorals major muscle that results in hypo plastic fused ribs, unilateral absence of breast nipple, areola, hemivertebrae, syndactyly, brachydactylyl, and in some cases dextrocardia.
The most common cytogenetic abnormality observed in spontaneously aborted fetuses is .
A physiological omphalocele should be resolved by the th week of gestation.
A MSAFP value above MoM will result in a prenatal screening test that indicates an increased risk for neural tube/abdominal wall defects.
A nuchal translucency (NT) measurement greater than mm will result in a prenatal screening test that indicates a greater than 20% chance for an underlying chromosome abnormality.
