VERTEBRAL COLUMN/SPINAL COLUMN - basic embryology

Question 1

What are the 3 layers of the embryo called?

Answer 1

ectoderm, mesoderm, endoderm

Question 2

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

Answer 2

notochord

Question 3

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

Answer 3

paraxial mesoderm

Question 4

What does paraxial mesoderm give rise to that will form the vertebral column?

Answer 4

somites

Question 5

Name the areas of cellular differentiation formed within the somite

Answer 5

sclerotome, myotome and dermatome

Question 6

what part of the somite will give rise to the vertebral column?

Answer 6

sclerotome

Question 7

List, in order, the names of the successive vertebral columns formed during development?

Answer 7

membranous, cartilaginous, skeletal or osseous

Question 8

Migration of sclerotomes 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 processes and costal processes

Question 10

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

Answer 10

intersegmental artery

Question 11

Cell proliferation within the perichordal blastema will result in what features?

Answer 11

a loose cranial scerotomite and a dense caudal sclerotomite

Question 12

What forms between the sclerotomies of a periochordal blastema

Answer 12

the intrasclerotomal fissure (fissure of von Ebner)

Question 13

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

Answer 13

the perichordal disc

Question 14

The perichordal disc in the presumptive location of what adult feature?

Answer 14

the intervertebral disc

Question 15

What is the earliest embryonic feature that will identify the position of the adult intervertebral disc?

Answer 15

the intrasclerotomal fissure (fissure of von Ebner)

Question 16

The union of a dense caudal scerotomite and a loose cranial sclerotomite from adjacent periochordal blastemae gives rise to what feature?

Answer 16

the vertebral blastema

Question 17

What vessel will be identified adjacent to the vertebral blastema?

Answer 17

the segmental artery

Question 18

when will cartilage first form in the membranous vertebral blastema?

Answer 18

beginning in the 6th embryonic week

Question 19

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

Answer 19

chondrification

Question 20

Chondrification begins in which region of the embryonic vertebral column?

Answer 20

the cervical region

Question 21

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

Answer 21

centrum center, neural arch center, transverse process center

Question 22

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

Answer 22

six: 2 for the centrum, 2 for the neural arch, 2 for each transverse process

Question 23

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

Answer 23

during the 7th embryonic week

Question 24

Ossification begins in which region of the embryonic vertebral column?

Answer 24

the lower cervical upper thoracic region

Question 25

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

Answer 25

primary centers appear in utero, secondary centers appear after birth

Question 26

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

Answer 26

3 primary centers: 5 secondary centers

Question 27

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

Answer 27

centrum centers and neural arch centers

Question 28

How many primary centers of ossification appear in the typical vertebra?

Answer 28

three: 1 for the centrum, 2 for the neural arches

Question 29

What is the classification of the joint forming between primary centers of ossification?

Answer 29

cartilage synchondrosis/amphiarthrosis synchondrosis

Question 30

What are the names of the synchondroses forming between primary centers of ossification in the typical vertebra?

Answer 30

neurocentral synchondrosis and neural arch synchondrosis

Question 31

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

Answer 31

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

Question 32

How many secondary centers of ossification appear in the typical vertebra?

Answer 32

five: 1 for the tip of each transverse process, 1 for the tip of the spinous process, 1 for each epiphyseal plate

Question 33

What are the names of the synchondroses forming between secondary centers of ossification and the rest of the typical vertebra?

Answer 33

tip of the transverse process synchondrosiss, tip of the spinous process synchondrosis, and epiphyseal ring synchondrosis

Question 34

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

Answer 34

during puberty, typically ages 11-16 years old