Vertebral column
Anatomy
The vertebral column, also known as the backbone or spine, is a complex structure that forms the main part of the axial skeleton. It is composed of a series of small bones known as vertebrae. These are stacked one on top of another to form a column.
The vertebral column extends from the base of the skull to the pelvis. It serves multiple vital functions, including protecting the spinal cord, supporting the body’s weight, and providing a structure for muscle attachment. The vertebral column is divided into five regions: cervical, thoracic, lumbar, sacral, and coccyx, each with a different number of vertebrae.
Cervical Vertebrae
The cervical region of the vertebral column is made up of seven vertebrae (C1-C7). The first two vertebrae, C1 and C2, are highly specialized and are given unique names: atlas and axis, respectively. They support the skull, allow the head to nod "yes" and shake "no". The remaining cervical vertebrae (C3-C7) are more classic vertebrae, providing flexibility and stability to the neck.
Thoracic Vertebrae
The thoracic region of the vertebral column consists of 12 vertebrae (T1-T12). These vertebrae are larger than the cervical vertebrae, as they have to support more weight. Each thoracic vertebra has facets on the sides of its body for articulation with the ribs, making this the only part of the spine connected to the rib cage.
Lumbar Vertebrae
The lumbar region of the vertebral column is made up of five large vertebrae (L1-L5). These are the largest unfused vertebrae in the spine, and they support the majority of the body's weight.
Sacral and Coccygeal Vertebrae
The sacral region of the vertebral column consists of five fused vertebrae (S1-S5) that form the sacrum. The sacrum fits between the two hip bones connecting the spine to the pelvis. Below the sacrum is the coccyx, formed from four fused vertebrae. The coccyx, also known as the tailbone, is the final segment of the vertebral column.
Function
The vertebral column performs several crucial functions. Firstly, it protects the spinal cord, which is the main pathway for communication between the brain and the rest of the body. Secondly, it supports the weight of the body and provides a rigid structure upon which muscles and ligaments can act to produce movement. Lastly, it acts as a flexible rod that can bend and twist, allowing for mobility and flexibility.
Clinical Significance
Due to its central role in the structure and function of the body, the vertebral column is subject to a range of disorders. These include scoliosis, a lateral curvature of the spine; kyphosis, an excessive outward curvature of the spine, causing hunching; and lordosis, an excessive inward curvature of the spine. Other conditions, such as herniated discs, spinal stenosis, and osteoporosis, can also affect the vertebral column.