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Ossification Centers
FAB - Ossification Centers
Question | Answer |
---|---|
Primary ossification centers begin before or after birth? | Before |
Secondary ossification centers begin before or after birth? | after |
Ossification is the 1st, 2nd, etc.. stage of vertebral development? | the Last stage |
What happens in chondrification? | The embryo has the mesodermal layer being replaced by the cartilage. |
When has chondrification completed? | Usually by the 3rd fetal month |
When does ossification occur, time wise? | In the 10th week of embryonic development. |
When are primary ossification centers usually completed? | By 3 to 6 yrs of age |
In cervical vertebrae except C1 & C2, where are the primary ossification centers? | 1 in vert body; 1 in each of the vert arches (lamina and pedicles) |
Where are the 2ndary ossif. centers in C3-C7? | epiphyseal plates of the vert body, tip of each TP, and tip of each SP |
Where are primary ossif. centers in all thoracic vert? | 1 in vert body; 1 in each of the vert arches (lamina and pedicles) |
Where are 2ndary ossif. centers in all thoracic vert? | epiphyseal plates of the vert body, tip of each TP, and tip of each SP |
Time wise, when do 2ndary centers appear and complete? | Appear during 18th yr of life, completed by 25. |
Where are the secondary ossifications of the Lumbar? | epiphyseal plates of the vert body, tip of each TP, and tip of each SP |
Where are the 1 ossif. centers of ATLAS? | 1 in each of lateral masses. |
Where are the 2ndary ossif. centers of ATLAS? | On the anterior arch. |
Where are the prim. ossif. centers of C2? | 1 in the body, 1 in each arch, 2 in base of odontoid process. |
Where are the 2ndary ossif. centers of C2? | 1 in apex of dens. 1 @ bottom of vert body where ant-inf. lipping starts. |
The mesodermal stage is marked by the ____condensation of the ___ ____ around the ____. | mesenchymal; paired sclerotomes; notochord |
What happens to each of the sclerotomes during the mesodermal stage? | They become more dense |
In mesodermal stage, how do the sclerotomes get separated in half? | a horizontal fissure aka intervertebral fissure occurs to separate the sclerotomes in half |
Where does chondrification initially appear? | In the cervical region. |
What's the purpose of the primary ossif. centers | To protect the spinal cord |
Where do primary ossif. centers begin and progress? | Begin in lower thoracic or upper lumbar and progress to cervical spine. |
Which sections of the spine are last to show ossification? | sacral and coccygeal |
How many primary ossif. centers do C3-C7 and thoracic have? | 5 |
How many secondary ossif. centers do C3-C7 and thoracic have? | 5 |
How many primary ossif. centers do lumbar vertebrae have? | 7 |
Where are the prim. ossif. centers of lumbar? | 1 in vert body, 1 in each arch, 1 in each mamillary process |
How many prim. ossif. centers of atlas? | 2 |
How many second. ossif. centers of atlas? | 1 |
How many prim. ossif. centers of axis? | 7 |
How many sec. ossif. centers of axis? | 2 |
Where are the prim. ossif. centers of sacrum? | 1 in body of each segment; 1 in each vert arch of each segment; 2 on anterior part of each side of S1, S2, S3 only |
Where are the sec. ossif. centers of sacrum? | 1 in each epiphyseal plate in each segment; 1 in each auricular surface. |
How many prim. ossif. centers in coccyx? | ZERO |
How many sec. ossif. centers in coccyx? | 1 in center of each segment |
What is a hemivertebra? | A failure of 1 lateral half of vert. to develop or ossify with the opposite half. |
What is a butterfly vertebra? | A malformation in posterior vertebral segments (mostly laminae) |
In a buttefly vertebra, what happens to the ossif. centers? | Lateral ossif. centers fail to grow and unite ENOUGH |
What is a block vertebra? | A failure of the formation of IVD resulting in fusion of adjacent vert. fusion during ossification. |
What are 2 types of block vertebra? | Congenital & acquired/surgical |
What's the appearance of congenital block vert. on x-ray? | Flat, smooth, peripheral surface in region of missing intersegmental disc. |
What's the appearance of acquired/surgical block vert. on x-ray? | appears prominent and irregular at disc level. |
What is spina bifida? | Failure of fusion of lamina of arch during embryonic period. |
What % of population has spina bifida? | 10% |
What are transitional vertebra? | Vertebra in 1 region of spine takes on appearance of vert they are approaching |
What % of ppl have sacralization? | 5% |
What is sacralization? | When L5 vert is partially or completed fused into sacrum |
What is lumbarization? | When S1 does not fuse w/ sacrum. Feels like a 6th lumbar vertebra. |
What is spondylosis? | General degeneration of spinal column. |
What is spondylolysis? | A defect in interarticular part of vert. |
Which segment of spine is spondylolysis usually seen ? | Lumbar |
What is spondylolosthesis? | Slippage of vert. body on vert below. |
Which segment of spine is spondylolosthesis usually seen? | Lumbar |