VERTEBRAL COLUMN/SPINAL COLUMN - basic embryology Flashcards
What are the 3 layers of the embryo called?
ectoderm, mesoderm, endoderm
Invagination of ectoderm along the primitive streak gives rise to what embryonic structure?
notochord
What is the name given to the mesoderm that will give rise to the vertebral column?
paraxial mesoderm
What does paraxial mesoderm give rise to that will form the vertebral column?
somites
Name the areas of cellular differentiation formed within the somite
sclerotome, myotome and dermatome
what part of the somite will give rise to the vertebral column?
sclerotome
List, in order, the names of the successive vertebral columns formed during development?
membranous, cartilaginous, skeletal or osseous
Migration of sclerotomes to surround the notochord forms what developmental feature?
the perichordal blastema
The perichordal blastema gives rise to what processes?
neural processes and costal processes
What is the name of the artery located between adjacent perichordal blastemae?
intersegmental artery
Cell proliferation within the perichordal blastema will result in what features?
a loose cranial scerotomite and a dense caudal sclerotomite
What forms between the sclerotomies of a periochordal blastema
the intrasclerotomal fissure (fissure of von Ebner)
The intrasclerotomal fissure (fissure of von Ebner) gives rise to what developmental feature?
the perichordal disc
The perichordal disc in the presumptive location of what adult feature?
the intervertebral disc
What is the earliest embryonic feature that will identify the position of the adult intervertebral disc?
the intrasclerotomal fissure (fissure of von Ebner)
The union of a dense caudal scerotomite and a loose cranial sclerotomite from adjacent periochordal blastemae gives rise to what feature?
the vertebral blastema
What vessel will be identified adjacent to the vertebral blastema?
the segmental artery
when will cartilage first form in the membranous vertebral blastema?
beginning in the 6th embryonic week
What is the name given to the replacement of mesoderm by cartilage?
chondrification
Chondrification begins in which region of the embryonic vertebral column?
the cervical region
What are the names given to the centers of chondrification within the vertebral blastema?
centrum center, neural arch center, transverse process center
How many centers of chondrification typically appear in the vertebral blastema?
six: 2 for the centrum, 2 for the neural arch, 2 for each transverse process
What is the earliest time that centers of ossification appear in the cartilaginous vertebra?
during the 7th embryonic week
Ossification begins in which region of the embryonic vertebral column?
the lower cervical upper thoracic region
What is the name given to centers of ossification based on time of appearance?
primary centers appear in utero, secondary centers appear after birth
What is the ratio of primary to secondary centers of ossification for a typical vertebra?
3 primary centers: 5 secondary centers
What are the names of the primary centers of ossification for a typical vertebra?
centrum centers and neural arch centers
How many primary centers of ossification appear in the typical vertebra?
three: 1 for the centrum, 2 for the neural arches
What is the classification of the joint forming between primary centers of ossification?
cartilage synchondrosis/amphiarthrosis synchondrosis
What are the names of the synchondroses forming between primary centers of ossification in the typical vertebra?
neurocentral synchondrosis and neural arch synchondrosis
What are the names of the five secondary centers of ossification for a typical vertebra?
tip of the transverse process, tip of the spinous process, epiphyseal plate centers
How many secondary centers of ossification appear in the typical vertebra?
five: 1 for the tip of each transverse process, 1 for the tip of the spinous process, 1 for each epiphyseal plate
What are the names of the synchondroses forming between secondary centers of ossification and the rest of the typical vertebra?
tip of the transverse process synchondrosiss, tip of the spinous process synchondrosis, and epiphyseal ring synchondrosis
What is the range of appearance for secondary centers of ossification of a typical vertebra?
during puberty, typically ages 11-16 years old
