1. Vertebrae

2. Vertebral column Extends from skull to pelvis Consists of many vertebrae separated by cartilaginous intervertebral disks that are connected by ligaments Forms central axis of the skeleton

3. Supports the head and the trunk of the body Flexible to permit movements Protects the spinal cord

4. How many vertebrae do we have? Adult: 26 Infant: 33 separate bones –Five vertebrae fuse to form the sacrum and four others join to become the coccyx

5. Components of vertebral column Cervical vertebrae Thoracic vertebrae Lumbar vertebrae Sacrum coccyx

7. Curvatures of vertebral column fig 7.34 Names correspond to the regions in which they occur 1. thoracicconcave anteriorly (primary 2. pelviccurves) 3. cervicalconvex anteriorly (2ndary 4. lumbar curves)

9. 3 parts of Vertebra Body: (centrum) –Transfers weight along the axis; separated by intervertebral discs Arch: surrounds vertebra foramen Articular process: –Intervertebral foramina: gaps b/t ea vertebra; permits passage of nerves to or from spinal cord

11. Cervical Vertebrae Comprise the bony axis of the neck Smallest of the vertebrae, but tissue are denser than those in any other region of column Allows for 180 degree range of motion Atlas: (C1) holds up head –Practically no body or spine –Pivots around the dens of axis Axis: (C2) during development fuses with atlas

12. Atlas: (C1) holds up head –Practically no body or spine –Pivots around the dens of axis Axis: (C2) during development fuses with atlas

13. Atlas

14. Axis

15. Distinctions of Cervical Transverse processes of cervical are DISTINCT b/c of transverse foramina –Passageways for arteries leading to the brain Spinous processes: Uniquely forked (bifid): provide attachment for muscles Vertebra prominens: longer and protrudes beyond other cervical (can be felt thru skin)

17. Thoracic Vertebrae Total of 12 Larger than cervical Long pointed spinous process slopes downward Bear increasing loads of body weight due to the increase in the body size of the vertebra

18. Thoracic Demi facets: on side of body to articulate with ribs Injury: compression-dislocation fractures of vertebrae occur b/t throacic and lumbar due to heavy weight bearing load

20. Lumbar Total of 5 in small of back Supports more weight b/c of larger and stronger bodies Transverse processes project posteriorly at sharp angles Large Bodies

21. Lumbar Short spinous processes are nearly horizontal: provide surface area for muscle attachment of lower back muscles Smaller vertebral foramen Injuries: Compression, Slip Disk

23. Sacral Vertebrae fig 7.39 Originates as 5 vertebrae Complete fusion by age 25 (18-30)

24. Dorsal sacral foramina: blood vessels pass thru sacral promontory: first sacral vertebra Sacral canal: opening Sacral hiatus: opening at end of sacrum Sacral foramina: 4 pairs that provide passageways for blood vessels and nerves

26. Coccygeal Originates as 4 vertebra, fuses as 1 bone Fusion of time varies Attached by ligaments to margins of the sacral hiatus