Vertebral column (English)

Vertebral column seen from the anterior perspective. The individual vertebrae of each of the 5 regions are labelled. Each vertebra is named in numerical order within their region from superior to inferior. The first region, the cervical spine, consists of 7 vertebrae. The first (C1) and second (C2) vertebrae are particularly unique in their anatomical appearance and are known as the atlas and axis, respectively. The seventh cervical vertebra (C7) is also known as the vertebra prominens. The second segment, the thoracic spine, is the longest portion of the vertebral column and comprises 12 vertebrae which house the heads of the ribs. Moving inferiorly, there is a shorter region called the lumbar spine. This region consists of 5 vertebrae. The most inferior portion of the spine consists of two bones (sacrum and coccyx) composed of fused vertebral bodies. The sacrum comprises 5 vertebrae, while the coccyx can have a variable number of vertebrae (usually 3 to 5). When observed from the lateral aspect, the vertebral column presents four curvatures: two concavities and two convexities. The curvatures that are concave anteriorly are called the thoracic and sacral kyphoses. The curvatures that are convex anteriorly are known as the cervical and lumbar lordoses.