Overview
This lecture covers the anatomical differences among cervical, thoracic, and lumbar vertebrae, focusing on unique features and identification strategies for each vertebral type.
Cervical Vertebrae (C1–C7)
- There are seven cervical vertebrae, abbreviated as C1–C7.
- C1 (atlas) is flat, round, lacks a vertebral body, and articulates with the skull's occipital condyles.
- C2 (axis) has a unique upward projection called the dens, forming a pivot joint for head rotation ("no" movement).
- C1 allows rocking head motion ("yes" movement); C2 enables rotational movement.
- C3–C7 generally look similar, sometimes have bifid (split) spinous processes.
- All cervical vertebrae have transverse foramina (openings in the transverse processes) for vertebral artery passage.
- Transverse foramina are a key identifying feature of cervical vertebrae.
Thoracic Vertebrae (T1–T12)
- There are twelve thoracic vertebrae, T1–T12; individual identification is not required.
- Thoracic vertebrae have sharply downward-tapering spinous processes and large transverse processes.
- The vertebral foramen is round in shape.
- The body shape is distinct; transverse processes provide rib attachment sites.
- Nicknamed “giraffe” due to their shape.
Lumbar Vertebrae (L1–L5)
- There are five lumbar vertebrae, L1–L5.
- Lumbar vertebrae have large, wide bodies for weight bearing.
- The spinous process is short, thick, rectangular ("moose" appearance).
- Transverse processes are slender, not suited for rib attachment.
- Vertebral foramen is more oval than round.
Vertebrae Identification Tips
- Cervical: Presence of three openings (vertebral foramen + two transverse foramina).
- Thoracic: Large, robust transverse processes for ribs; sharply downward spinous processes.
- Lumbar: Large, wide body; short, blunt spinous process; slender transverse processes.
Key Terms & Definitions
- Atlas (C1) — First cervical vertebra, supports the skull, allows nodding.
- Axis (C2) — Second cervical vertebra, contains the dens for head rotation.
- Dens — Peg-like projection on C2, enabling pivot movement.
- Transverse Foramina — Openings in cervical vertebrae for vertebral arteries.
- Superior Articular Facet — Flat surface on vertebra for articulation with adjacent bones.
- Spinous Process — Posterior projection for muscle and ligament attachment.
Action Items / Next Steps
- Practice identifying vertebrae types and unique structures in lab models.
- Review diagrams/images of cervical, thoracic, and lumbar vertebrae to reinforce identification.