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 C1 to C7)
– First two vertebrae are Atlas (C1) and Axis (C2)
• Allow for the movement/rotation of skull• Do not have a body• Atlas articulates with the occipital condyles of
the skull
– C3 through C7 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 T1 to T12)
– 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 L1 to L5)
– 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 L5 vertebra and superior to the coccyx– Formed from the fusion of five vertebrae– Alae are winglike projections that articulate
laterally 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