Vertebrae are the individual bones that make up the backbone, also known as the spinal column.

Here's a breakdown:

* Structure: Vertebrae are irregularly shaped bones with a central hole (vertebral foramen) that allows the spinal cord to pass through. They have various projections (processes) that serve as attachment points for muscles and ligaments.

* Function: Vertebrae provide support and structure for the body, protect the spinal cord, and allow for flexibility and movement.

* Types: There are 33 vertebrae in the human body, divided into five regions:

* Cervical vertebrae (7): Support the head and neck.

* Thoracic vertebrae (12): Connect to the ribs and form the chest cavity.

* Lumbar vertebrae (5): Support the lower back and abdomen.

* Sacral vertebrae (5): Fused to form the sacrum, which connects to the pelvis.

* Coccygeal vertebrae (4): Fused to form the coccyx (tailbone).

* Intervertebral discs: Between each vertebra is a cartilaginous disc that acts as a shock absorber and allows for flexibility.

Let me know if you have more questions about the vertebrae!