Vertebral Column

Overview

The vertebral column, also known as the spine, is a central structure in the human skeleton that provides support, protection for the spinal cord, and flexibility. It is composed of individual vertebrae, which vary in structure depending on their location (cervical, thoracic, lumbar).

• Body: The thick, disc-shaped anterior portion of the vertebra that bears weight.

• Spinous Process: The posterior projection that can be felt through the skin; serves as an attachment point for muscles and ligaments.

• Pedicle: The short, thick processes that project posteriorly from the vertebral body, forming the sides of the vertebral arch.

• Lamina: The flattened or arched part of the vertebral arch, forming the roof of the spinal canal.

• Vertebral Foramen: The opening formed by the vertebral arch and body, through which the spinal cord passes.

• Superior and Inferior Facets (Articular Processes): Projections that articulate with adjacent vertebrae, allowing for movement and stability.

• Transverse Foramen (Cervical Only): Openings in the transverse processes of cervical vertebrae for the passage of the vertebral artery.

• Anterior and Posterior Arches (Atlas/C1 Only): Unique structures of the first cervical vertebra (atlas) that support the skull.

• Odontoid Process/Dens (Axis/C2 Only): A tooth-like projection on the second cervical vertebra (axis) that allows rotation of the head.

Key Points

• Cervical Vertebrae: Have transverse foramina and small bodies; atlas (C1) and axis (C2) are specialized for head movement.

• Thoracic Vertebrae: Larger bodies, long spinous processes, and facets for rib articulation.

• Lumbar Vertebrae: Largest bodies, short spinous processes, and robust structure for weight-bearing.

Example

When asked to identify a vertebra, look for the presence of transverse foramina (cervical), facets for rib articulation (thoracic), or large, robust bodies (lumbar).

Sternum

Overview

The sternum, or breastbone, is a flat bone located in the center of the chest. It serves as an attachment point for ribs and protects vital organs such as the heart and lungs.

• Manubrium: The upper portion of the sternum, articulates with the clavicles and first ribs.

• Body: The central, elongated part of the sternum, articulates with costal cartilages of ribs 2-7.

• Xiphoid Process: The small, cartilaginous lower tip of the sternum, which ossifies with age.

• Costal Cartilage: Bars of hyaline cartilage that connect the ribs to the sternum; true ribs attach directly, false ribs do not.

Key Points

• True Ribs: Ribs 1-7, attach directly to the sternum via costal cartilage.

• False Ribs: Ribs 8-12, do not attach directly to the sternum.

Example

The xiphoid process is a landmark for CPR hand placement.

Ribs

Overview

Ribs are curved bones that form the rib cage, protecting the thoracic organs and assisting in respiration. Each rib has distinct anatomical features.

• Head: The end of the rib that articulates with the vertebral column.

• Tubercle: A small bump near the head that articulates with the transverse process of a vertebra.

• Body/Shaft: The long, curved portion of the rib.

Key Points

• True Ribs: Attach directly to the sternum.

• False Ribs: Attach indirectly or not at all to the sternum.

Example

The head of the rib fits into the costal facet of the vertebra, forming a joint for movement during breathing.

Comparison Table: Vertebral Structures

Additional info: Table entries inferred from standard anatomical features of vertebrae.