2. Basic Embryology of the Vertebral Column Flashcards
What are the 3 layers of the embryo called?
ectoderm, mesoderm and 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, dermatome and myotome
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 periochordal blastema gives rise to what processes?
neural processes and costal processes
What is the name of the artery located between adjacent perichordal blasternae?
intersegmental artery
Cell proliferation within the perichordal blastema will result in what features?
a loose cranial sclerotomite and a dense caudal sclerotomite
What forms between the sclerotomites of a perichordal blastema?
the intrasclerotomal fissure (fissure of von Ebner)
What is the earliest embryonic feature that will identify the postion of the adult intervertebral disc?
the intrasclerotomal fissure (fissure of von Ebner)
The union of a dense caudal sclerotomite and a loose cranial sclerotomite from adjacent perichordal blasternae gives rise to what feature?
the vertebral blastema
What vessel will be identified adjacent to the vertebral blastema?
the segmental artery
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 transver process
What is the earlies time that centers of ossificationappear in the cartilaginous vertebra?
During the 7th embryonic week
What is the ratio of primaryt 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
What is the classification of the joint forming between primary centers of ossification?
cartilage synchondrosis/ampiarthrosis synchondrosis
What are the names of the synchondroses forming between primary centers of ossification in the typical vertebra?
neurocentral synchondrois and neural arch synchondrosis
What are the names of the 5 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 a 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 is the classification of the joint forming between secondary centers of ossification and rest of the typical vertebra?
cartilage synchondrosis/ampiarthrosis synchondrosis
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 synchondrosis, tip of the spinous process synchondrosis, and epiphyseal ring synchondrosis
What is the range of apearance for secondary centers of ossification of a typical vertebra?
during puberty, typically ages 11-16 years old
