The spine’s natural curves, either lordotic or kyphotic, provide resistance and elasticity as body weight is distributed and axial loads are supported during movement. Vertebral bodies are the weight-bearing structures of the spine as upper body weight is absorbed throughout the spine. The vertebrae perform many important functions that preserve the spine’s overall health and function.
So now that we have talked about the number and characteristics of vertebrae that make up each of the spine’s main sections, let’s explore the actual purpose of the vertebrae. The last lumbar vertebra (L5) moves with the sacrum, and below the sacrum are 5 additional vertebrae, fused together to form the coccyx, commonly known as the ‘tailbone’. The sacrum rests between the two hip bones that connect the spine to the pelvis. The sacral spine includes 5 vertebrae, abbreviated as S1 - S5, and these vertebrae are fused together into a triangular shape (sacrum). While not commonly included in discussions of the spine’s main sections, there is also the sacral spine, which the lumbar spine connects with. The lumbar vertebrae are the largest of the spine. The lumbar vertebrae (L1 - L5) also get larger from 1 to 5, and these vertebrae bear the brunt of the body’s weight and related biomechanical stress, which is why lower back pain is such a common complaint. The thoracic vertebrae have long spinous processes, which are the bumps of the spine that you can see and feel if you run your fingers down the length of the spine, and it’s the many connections between the ribs and vertebrae, along with the long spinous processes, that limit the thoracic spine’s range of motion. These vertebrae join with the rib cage but don’t attach at T11 and T12, which is why these ribs are referred to as ‘floating ribs’. The thoracic vertebrae include T1 - T12 and increase in size from 1 to 12.
The cervical vertebrae are the smallest of the spine. The second cervical vertebra, axis (C2), is referred to as the ‘dens’ or ‘odontoid process’ and acts as a type of pivot and collar, allowing the head and atlas to rotate around the dens so the head can be moved from side to side, up and down, and forward and back. The atlas (C1) is the first cervical vertebra, and this cervical vertebra supports the weight of the skull. The cervical spine is further divided into two sections: the upper cervical region with the C1 and C2 vertebrae and the lower cervical region with the remaining C3 to C7 vertebrae.Ĭ1 is referred to as the ‘atlas’, while C2 forms the ‘axis’. The cervical spine includes 7 vertebrae and are abbreviated as C1 - C7 the thoracic spine includes 12 and are abbreviated as T1 - T12, and the lumbar spine has 5, abbreviated as L1 - L5. The bones of the spine are known as ‘vertebrae’, and in a healthy spine, these bones are rectangular in shape and stacked on top of one another in a straight, neutral, and natural alignment.Įach spinal section houses a certain number of vertebrae. Now that we have talked about the three main spinal sections, let’s talk about the main component that makes up these sections: vertebrae. The cervical and lumbar spine features lordotic curves, with a healthy cervical lordosis ranging between 20 and 40 degrees and a healthy lumbar lordosis ranging from 40 to 60 degrees a healthy kyphotic curve of the thoracic spine ranges between 20 and 40 degrees.Īs you can see, even in a healthy spine, there is a natural curvature range, but when spinal curves fall beyond that healthy range, this indicates the presence of a spinal condition that can cause problems in the future, especially if left untreated, or not treated appropriately. There are two main types of curvatures, based on whether they bend forwards, towards the body’s center in a soft ‘C’ shape, or backwards, away from the body’s center in a reverse ‘C’ shape the term ‘lordosis’ refers to the spine’s curvatures that bend backwards, away from the body’s center, while ‘kyphosis’ refers to a forward-bending curve. The spine is naturally curved because it makes it stronger, more flexible, and facilitates the even distribution of weight and stress that occurs during movement, and this is important because a variety of common spinal conditions involve a loss of the spine’s healthy curves.
The cervical spine refers to the neck the thoracic spine includes the middle and upper back, while the lumbar spine includes the lower back.Įach section has a corresponding curvature, which is why when viewed from the front and/or back, the spine appears straight, but when viewed from the side, it has a soft ‘S’ shape. The spine is made up of three main sections: cervical, thoracic, and lumbar. Spinal Conditions and the Spine’s Structure.