Vertebral Development PDF

Vertebral Development Prepared and Presented By Hung Bui D.C. Ovulation to Implantation Ovulation to Implantation Bilaminar stage Bilaminar stage Trilaminar stage (Gastrulation) Formation of notochord Neurulation Formation of neural tube Neurulation Somite formation Neurulation Vertebral Development...

Vertebral Development Prepared and Presented By Hung Bui D.C. Ovulation to Implantation Ovulation to Implantation Bilaminar stage Bilaminar stage Trilaminar stage (Gastrulation) Formation of notochord Neurulation Formation of neural tube Neurulation Somite formation Neurulation Vertebral Development There are 3 stages of vertebral development: 1. Mesodermal stage: happens around 4th week of development and completes around 6th week. 2. Chondrification 3. Ossification stage 1. Mesodermal Stage Migration of messenchymal condensation of pair sclerotomes: – around notochord to form the body (centrum) - Around the neural tube to form the neural arches (pedicles, lamina, SPs, APs) - Laterally to form the TPs. 1. Mesodermal Stage Around the notochord the scleretomal segments start: Formation of horizontal fissure called intervertebral fissure (aka. perichordal disc) which divides the sclerotomal segment into 2 halves (cephalic and caudal halves) Fusion of caudal half of segment above with cephalic half of segment below to form the centrum (vertebral body) Formation of the IVD from the Intervertebral fissure and the notochord (nucleus pulposus). 1. Mesodermal Stage Intervertebral Fissure Cephalic Caudal 2. Chondrification Chondrification stage: happens around 4th week of development and completes in 3rd fetal month In this stage the mesodermal layer is completely replaced by the cartilage It starts initially from the cervical region and progresses to other regions. 3. Ossification Ossification happens as early as 10th week of development and completes in 25th years of age. There are 2 stages of ossification: 1. Primary ossification centers: happens before birth during fetal life and can be completed after birth. 2. Secondary ossification centers: happens after birth and completed at different ages for different bones. The latest was 25th years of age Centers of Ossification 1. Atlas (C1): Primary ossification: 2 in total – 1 on the tips of each lateral mass (2) and pread posteriorly to form posterior arch. – Occurs early in fetal life(7th wk) and complete usually at birth Secondary ossification: only 1 center – 1 on arterior arch and spreads posteriorly to unite with the lateral masses and forms the anterior arch – Occurs around birth and completes around 8th year of age Total of 3 ossification centers Centers of Ossification 2. Axis (C2, Epistropheus): Primary ossification: (7) – 1 in each vertebral arch (2nd fetal month) – 1 in the vertebral body (4th fetal month) – 2 in base of odontoid (6th fetal month) Secondary ossification:(2) – 1 in apex of odontoid process – 1 at the bottom of vertebral body. Both primary and secondary centers occur and complete at different age range from 2-12yrs after birth. Total of 9 ossification centers Centers of Ossification 3. C3-C7 and T1-T12: Primary ossification: protection of spinal cord. There are 5: – – – – – Secondary ossification: formation where balance of vertebral structures. There are 5: – – – – 1 in body 1 on each lamina(2) 1 on each pedicle (2) Occurs in different ages depend on each vertebra. General rule, occurs in lower thoracic or upper lumbar region and spreads to cervical. The sacrum and coccyx are last. Completes around 3-6yrs of age. 1 each epiphyseal plate (2) 1 on spinous process (1) 1 on each transverse process (2) Occurs around 17th-18th year of age and completes by age 25. Total of 10 ossification centers Centers of Ossification 4. L1-L5: The primary centers: in lumbar vertebrae are the same as thoracic except there are 2 more primary ossification centers located 1 on each mammillary process. Total is 7. The secondary ossification centers of lumbar vertebrae are the same as the thoracic. Total is 5. Subtotal of 12 ossification centers Centers of Ossification 5. Sacrum: Primary ossification: – – – – – – 1 in each body 1 on each pedicle of each segment 1 on each lamina of each segment 2 in the anterior portions on each side of 1,2,3 segments only Total: ??? Occurs in different time 8th week to 8th month of fetal life Secondary ossification: – 1 in each epiphyseal plate (16th yr.) – 1 on each auricular surface (18th 20th yr.) – Total: ??? – Completes around 25th yr. of age Centers of Ossification 6. Coccyx: Primary ossification: None Secondary ossification: – One on the center of each individual segment – Occurs at different times for each segment(#1:1-4th yr., #2: 5-10th yr., #3: 1015th yr., #4: 14-20th yr.) and completes and fuses around 25-30 years of age. Clinical Abnormalities 1. Hemivertebra: This happens during embryonic migration of sclerotomes. One side of the sclerotomes has failed to migrate toward the notochord leading to failure of ossifying development of one half of a vertebra. The hemivertebra occurs in wedged shape on X-ray. Clinical Abnormalities 2. Butterfly Vertebra: Happens due to not uniting of both halves of the vertebral body Insufficiently grow and unite of lateral ossification centers. Clinical Abnormalities 3. Block vertebra: Fusion of 2 or more vertebrae due to failure to form IVD Two types: I. Congenital II. Acquired Congenital Acquired Clinical Abnormalities 4. Spina Bifida: Happens due to failure of the laminae of the neural arch during embryonic period 10% of population Common in L5-S1 “turf of hair” Clinical Abnormalities 5. Sacralization: Happens when L5 partially or completely incorporated into sacrum. 5% population Clinical Abnormalities 6. Lumbarization: Happens when S1 does not fuse to S2 leads to extra lumbar segment (L6). Clinical Abnormalities 7. Spondylosis: Spondylo – the spine/vertebrae Due to degeneration of spinal column Clinical Abnormalities 8. Spondylolysis: Fracture in one side or both sides of the interarticular part (pars interarticularis) Usually found in lumbar region Clinical Abnormalities 9. Spondylolisthesis: Slippage of the vertebral body of the vertebral above on the vertebral below it or L5 upon the sacrum due to: I. II. Elongation of pedicles Bilateral Fx of Par articularis Usually in L5 Clinical Abnormalities 10. Tropism: Asymmetrical orientation of the articulating facets Usually found in L5-S1 Clinical Abnormalities 11. Transitional Vertebra: This is not an abnormal condition. Occurs in 1 or 2 vertebrae at the area b/t 2 regions. I.e. C7, T11, T12 T12 T11 References Atlas of Human Anatomy. Netter, F. ICON Learning Systems. Basic and Clinical Anatomy of the Spine, Spinal Cord and ANS. Ch. 12, 541-560 by Cramer, G. and Darby, S. Mosby. Clinical Oriented Anatomy, Moore, etal. Lippincott Williamsand Wilkins, Baltimore, Novyland. Correlative Spinal Anatomy. Douglas Gates, D.C.. 3rd printing 1984. http://cdn.yourarticlelibrary.com/wp-content/uploads/2013/10/image50.png https://image.slidesharecdn.com/embryonicdevelopmentafterfertilization-151019143142-lva1-app6892/95/embryonic-development-after-fertilization-5638.jpg?cb=1445268334 http://unbc.biol312.ca/wp-content/uploads/2016/02/gastru.png https://classconnection.s3.amazonaws.com/264/flashcards/1854264/jpeg/notochord1348419211920.jpeg http://ib.bioninja.com.au/_Media/neurulation_med.jpeg https://odontologi.wikispaces.com/file/view/neurulation1336080437307.jpg/548907746/800x508/neurulation1336080437307.jpg https://s3-us-west-2.amazonaws.com/courses-images/wp-content/uploads/sites/1940/2017/05/31173435/69-3d4f-4175-bd35-9dbdc1314c81.png https://image.slidesharecdn.com/developmentofvertebralcolumn-100302145406-phpapp02/95/development-of-vertebral-column-16-728.jpg?cb=1267541703 http://skeletalsystemdev.weebly.com/uploads/7/0/4/3/7043675/2458583_orig.png https://clinicalgate.com/wp-content/uploads/2015/03/B9780443066849500524_gr8.jpg http://img.tfd.com/dorland/hemivertebra.jpg https://www.spineuniverse.com/sites/default/files/legacy-images/lonner2arrow_copy-99.jpg http://www.harms-spinesurgery.com/src/plugin.php?m=harms.2560.preview&t=file&nocache=1&ism=off https://ajns.paans.org/IMG/jpg/Figure11.jpg http://conni60640-ivil.tripod.com/sitebuildercontent/sitebuilderpictures/blockverts.jpg https://asianspinejournal.org/ArticleImage/9998ASJ/asj-9-895-g003-l.jpg https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTejB6jr4od3ak030ez9axIbkMpphRR8JhqFauZDaJq-ZWiJ9TY https://upload.wikimedia.org/wikipedia/commons/thumb/7/7e/Spina-bifida.jpg/1200px-Spina-bifida.jpg http://www.spinabifida.net/wp-content/uploads/2015/01/Spina-Bifida-Occulta-Picture21.jpg https://upload.wikimedia.org/wikipedia/commons/5/51/Sacralization_of_the_fifth_lumbar_vertebra.jpg https://millerfamilychiropractic.wordpress.com/files/2009/10/c-cong.jpg http://callisto.ggsrv.com/imgsrv/FastFetch/UBER1/ZI-4WWZ-2013-APR00-IDSI-79-2 https://upload.wikimedia.org/wikipedia/commons/c/c8/Lumbarization_of_S1.jpg http://fscomps.fotosearch.com/compc/LIF/LIF136/ga207004.jpg http://www.lumbarspondylosis.net/wp-content/uploads/2015/06/lumbar-spondylosis.jpg https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ0kyQFnxiaSF32r-WllrtVqygatuITmDwv-NkIAgPhCk4vW1cC https://44wj5q2j6wo23s4mp6owjohh-wpengine.netdna-ssl.com/wp-content/uploads/2013/01/spondylolithesis.jpg http://3.bp.blogspot.com/-ks389PapFpM/U9GfOE_bDiI/AAAAAAAAAMI/t-QPzhcO0Ls/s1600/c7.png