Corpus: Vertebra

A vertebra is the fundamental bony structure of the spinal column. In a typical human spine, there are 34 vertebrae.

The vertebrae are grouped based on their location in the spine:

• Cervical vertebrae (7)
• Thoracic vertebrae (12)
• Lumbar vertebrae (5)
• Sacral vertebrae (5)
• Coccygeal vertebrae (4-5)

3.1. Basic structure

Each vertebra consists of a vertebral body, a vertebral arch, and various processes, which differ depending on the location of the vertebra. The vertebral body is the load-bearing part of the bone. The compact bone layer of the vertebral body, which interfaces with the adjacent intervertebral discs, is called the superior plate (cranially) and the inferior plate (caudally).

The vertebral body and arch enclose the vertebral foramen. Collectively, the vertebral foramina form the vertebral canal, which houses the spinal cord.

Between the vertebral bodies of adjacent vertebrae lie intervertebral discs, which, together with the vertebral bodies, form the intervertebral symphysis. In the thoracic region, the vertebrae also articulate with the ribs at the costovertebral joints.

3.2. Vertebral processes

3.2.1. Spinous process

A single spinous process projects backward (dorsally) from the vertebral arch along the midline.

3.2.2. Transverse processes

Each vertebra has two paired transverse processes extending laterally. These vary in shape and size across different regions of the spine

3.2.3. Articular processes

Each vertebra has four articular processes, which connect with the articular processes of the neighboring vertebrae to form facet joints.

3.3. Ligaments

Numerous ligaments connect the anatomical components of the vertebrae, maintaining the stability of the spine.

3.3.1. Between the vertebral bodies

• Anterior longitudinal ligament: located on the front surface of the vertebral bodies.
• Posterior longitudinal ligament: located on the back surface of the vertebral bodies.

3.3.2. Between the vertebral arches

• Ligamenta flava

3.3.3. Between transverse and spinous processes

• Intertransverse ligaments: between the transverse processes.
• Interspinous ligaments: between the spinous processes.
• Supraspinous ligament: along the tips of the spinous processes.
• Nuchal ligament: connects the base of the skull to the supraspinous ligament.

3.3.4. Between the sacrum and coccyx

• Superficial posterior sacrococcygeal ligament
• Deep posterior sacrococcygeal ligament: a continuation of the posterior longitudinal ligament.
• Anterior sacrococcygeal ligament: a continuation of the anterior longitudinal ligament.
• Lateral sacrococcygeal ligaments

Vertebrae develop through endochondral and perichondral ossification from one central and two lateral bone precursors.

Osteoporosis can weaken the vertebral bodies, increasing the risk of fractures. Diagnosing osteoporosis requires ruling out other conditions that affect bone metabolism. It is typically diagnosed using X-rays or bone density testing (bone densitometry).