Axial Skeleton The Vertebral Column The Vertebral Column

Axial Skeleton The Vertebral Column

The Vertebral Column • Extends from skull (supports the skull) to the pelvis (distributes weight to lower limbs) • Five sections: cervical, thoracic, lumbar, sacrum, coccyx • Born with 33 vertebrae, but nine fuse into two bones (sacrum and coccyx) • Vertebrae separated by intervertebral discs

The Vertebral Column – Vertebrae Structure • Body/Centrum – disc-like part facing anteriorly • Vertebral arch – formed by joining of all posterior extensions of vertebra • Vertebral foramen – opening which spinal cord passes • Transverse processes – two lateral projections from arch • Spinous process – projection from posterior of arch • Articular processes – superior and inferior projections lateral to foramen that articulate with above vertebra

The Vertebral Column – Vertebrae Structure

The Vertebral Column – Cervical Vertebrae • 7 vertebrae (identified as C 1 to C 7) – First two vertebrae are Atlas (C 1) and Axis (C 2) • Allow for the movement/rotation of skull • Do not have a body • Atlas articulates with the occipital condyles of the skull – C 3 through C 7 are remaining cervical vertebrae • Smallest vertebrae • Contain transverse foramen • Spinous processes usually split in middle

The Vertebral Column – Cervical Vertebrae

The Vertebral Column – Thoracic Vertebrae • 12 vertebrae (identified as T 1 to T 12) – Connected with ribs – Typical shape, slightly modified for ribs • Includes costal facets to articulate with ribs in posterior • Spinous process long, pointed down

The Vertebral Column – Thoracic Vertebrae

The Vertebral Column – Lumbar Vertebrae • 5 vertebrae (identified as L 1 to L 5) – Bulkier shape – Hatchet-shaped spinous processes – Receives most of stress on vertebral column

The Vertebral Column – Lumbar Vertebrae

The Vertebral Column – Sacrum and Coccyx • Sacrum is inferior to the L 5 vertebra and superior to the coccyx – Formed from the fusion of five vertebrae – Alae are winglike projections that articulaterally with the hip bones – Forms posterior wall of pelvis – Includes median sacral crest and dorsal sacral foramina • Coccyx is inferior to sacrum – Formed from fusion of three to five tiny vertebrae – Commonly called the “tailbone”

The Vertebral Column – Sacrum and Coccyx
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