11 de março de 2024 Author: Maia Gonçalves The spine consists mainly of vertebrae and intervertebral discs. Its relative position is ensured by joints, tendons, ligaments, and muscles. Along with the bones of the head and thoracic cavity, the spine forms the axial skeleton and has several functions, including: Giving shape the body; Support weight; Stabilize the trunk, allowing it to remain straight and move in different directions: Forward or flexion; Backward or extension; To the right and left, or lateral flexion/extension; Rotation. Protect the spinal cord and the beginning of the nerves that originate from the spinal cord (spinal nerves); Human spine has 33 vertebrae. The first one articulates with the base of the skull, in the occipital bone, and the last corresponds to the tip of the coccyx. There are not two vertebrae exactly alike. However, most of them have a common structure that includes: Vertebral body: the most anterior area, similar to a cylinder, which is involved in spinal stability and weight support. The lower the vertebrae, the larger the vertebral body. Vertebral arch: the most posterior area, shaped like an arch. The overlapping of the vertebral arches of the vertebrae forms the spinal cavity or canal, where the spinal cord is housed. Processes or apophyses, which are bony projections or protrusions originating from the vertebral arch. The main differences between the vertebrae are related to the five spine regions which they belong. Regions of the spine The spine has five regions: Cervical with 7 vertebrae Thoracic or dorsal with 12 vertebrae Lumbar with 5 vertebrae Sacred with 5 vertebrae Coccygeal with 4 vertebrae In each region, the vertebrae can be designated by the initial of the region's name and order number counted from top to bottom. For example, C-4, T-3, L-2, etc. The seven cervical vertebrae are the bony base of the neck and allow movement of both the neck and head. The first two are the only ones that have specific names: The C-1 vertebra is called the atlas; The C-2 vertebra is called the axis and is responsible for the rotational movement of the head independent of the body. The 12 pairs of ribs articulate in the 12 thoracic vertebrae. The vertebrae of the lumbar spine have a larger body. They are involved in supporting the weight of the head, trunk and upper limbs and are the ones that have the most important intervention when carrying or lifting weights. The vertebrae move relative to each other, except in the sacral and coccygeal spine. Sacral and coccygeal spine are often referred to together as the sacrococcygeal spine. The five sacral vertebrae are fused and do not move with each other, and the same happens with the four coccygeal vertebrae. Except in the sacrococcygeal region, the faces of the vertebrae (the area facing the adjacent vertebra) are covered by cartilage which facilitates the vertebrae to slide past each other. Between adjacent vertebrae there are joints and intervertebral discs, which function as shock absorbers. Spine shape Normal spine is not straight. It has four natural curvatures that help mobility and cushion the effect of movements. Cervical lordosis or cervical lordotic curve: it is a posterior concavity (an arch forms forward) in the cervical region. Thoracic kyphosis or thoracic kyphotic curve: it is an anterior concavity (an arch forms backwards) in the thoracic region. Lumbar lordosis or lumbar lordotic curve: it is a posterior concavity (an arch forms forward) in the lumbar region. Sacred kyphosis: is an anterior concavity in the sacral spine. The first three curvatures of the spine are easily noticeable, the last is not visible externally. Meet the Orthopedic clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
