Vertebra T12

The twelfth thoracic vertebra T12 (12th thoracic vertebra) is a unique vertebra that serves as a transition between the thoracic and lumbar regions of the spine. Anatomically, T12 has several distinctive features:

1. Vertebral Body: The vertebral body of T12 is larger than those of the upper thoracic vertebrae but smaller than the lumbar vertebrae. It has a more cylindrical shape compared to the heart-shaped bodies of the upper thoracic vertebrae.

2. Transverse Processes: The transverse processes of T12 are shorter and more robust compared to those of the upper thoracic vertebrae. They lack the costal facets that are present in the upper thoracic vertebrae, as T12 does not articulate with ribs.[1]

3. Spinous Process: The spinous process of T12 is shorter and more horizontal compared to the more elongated and downward-sloping spinous processes of the upper thoracic vertebrae.

4. Articular Processes: The superior articular processes of T12 are oriented more like those of the thoracic vertebrae, facing posteriorly. In contrast, the inferior articular processes are oriented more like those of the lumbar vertebrae, facing laterally.[2]

5. Zygapophysial Joints: The zygapophysial joints at T12 exhibit a transition in orientation from the coronal plane (typical of thoracic vertebrae) to the sagittal plane (typical of lumbar vertebrae).[2]

6. Ligamentum Flavum: The ligamentum flavum at T12 covers a larger portion of the caudal lamina ventrally compared to the cranial lamina dorsally, which is consistent with the gradual increase in ligamentum flavum height and width from T1 to T12.[3]