Exam 1-Embryology of the Vertebral Column

Question 1

When does the embryonic disc form?

Answer 1

second week in utero

Question 2

When does gastrulation occur or 3-layered embryo form?

Answer 2

third week in utero

Question 3

Invagination of ectoderm along the primitive streak gives rise to what embryonic structure?

Answer 3

notochord

Question 4

What is the name given to the mesoderm that will give rise to the vertebral column?

Answer 4

paraxial mesoderm

Question 5

What embryonic structure gives rise to the somites?

Answer 5

paraxial mesoderm

Question 6

Name the areas of cellular differentiation formed within the somites

Answer 6

sclerotome, myotome,and dermatome

Question 7

What are the names of the successive vertebral columns formed during development?

Answer 7

membranous, cartilaginous, skeletal or osseous

Question 8

Migration of a somite pair to surround the notochord forms what developmental feature?

Answer 8

the perichordal blastema

Question 9

The perichordal blastema gives rise to what processes?

Answer 9

neural and costal processes

Question 10

What is the name of the artery located between adjacent perichordal blastema?

Answer 10

intersegmental artery

Question 11

What forms between the sclerotomites of a perichordal blastema?

Answer 11

the intrasclerotomal fissure (fissure of von Ebner)

Question 12

The intrascleratomal fissure (fissure of von Ebner) gives rise to what developmental feature?

Answer 12

the perichordal disc

Question 13

The union of a dense caudal sclerotomite and a loose cranial sclerotomite from adjacent perichordal blastema gives rise to what feature?

Answer 13

the vertebral blastema

Question 14

What vessel will be identified adjacent to the vertebral blastema?

Answer 14

the segmental artery

Question 15

When will cartilage first form in the membranous vertebral blastema?

Answer 15

beginning in the 6th embryonic week

Question 16

What is the name given to the replacement of mesoderm by cartilage?

Answer 16

chondrification

Question 17

What are the names given to the center of chondrification within the vertebral blastema?

Answer 17

centrum center, neural arch center, transverse process center

Question 18

How many centers of chondrification typically appear in the vertebral blastema?

Answer 18

six…2 for the centrum, 2 for the neural arch, and2 for each transverse process

Question 19

What is the earliest time that centers of ossification appear in the cartilaginous vertebra?

Answer 19

during the 7th embryonic week

Question 20

What is name given to centers of ossification based on time of appearance?

Answer 20

primary centers appear in utero, secondary centers appear after birth

Question 21

What is the ratio of primary to secondary centers of ossification for a typical vertebrae?

Answer 21

3 primary centers: 5 secondary centers

Question 22

What are the names of the primary centers of ossification for a typical vertebrae?

Answer 22

centrum centers and neural arch centers

Question 23

What are the names/locations of the five secondary centers of ossification for a typical vertebra?

Answer 23

tip of the transverse process, tip of the spinous process, epiphyseal plate centers

Question 24

What is the range of appearance for secondary centers of ossification of a typical vertebra?

Answer 24

during puberty, typically ages 11-16 years old