Documentation:FIB book/Spine
Overview
Spinal Anatomy
The typical shape of a vertebrae consists of two primary structures, the vertebral body, which is positioned anteriorly, and the vertebral arch positioned posteriorly, as can be seen in Figure 1 [1]. The vertebral body is the component of the vertebrae that primarily carries the weight of the body and thus increases in size from the cervical spine through the lumbar spine as the load of the upper body increases [1]. The vertebral arch creates the lateral and posterior sections of the vertebral foramen, which together with the vertebral body outlines a hollow opening forming the vertebral canal with adjacent vertebrae through which the spinal cord extends from C2 to the beginning of the lumbar region of the spine [1]. The spinal cord does not extend the full length of the spine because the spinal cord grows slower than the vertebral column during development, resulting in the end of the spinal cord anywhere between T12 and L3 [1]. After the end of the spinal cord, the cauda equina extends the remaining length of the spinal cord, providing major nerve roots for lower body function [1].
Other important features of the vertebral body include characteristic projections located on the vertebral arch which serve as attachment points for muscles and ligaments, levers for muscle movement, and sites of articulation between adjacent vertebrae [1]. The vertebral elements also contain rib elements throughout the spinal column. Rib elements in the thorax articulate with the ribs through synovial joints while the remaining vertebral rib elements are fused costal elements incorporated into the transverse process of the vertebral body [1].
The spine consists of 33 vertebrae, categorized by location as cervical, thoracic, lumbar, sacral, and coccygeal vertebrae, each characterized by differing structure and movement at the various body regions [1]. These spinal segments can be seen in Figure 3 as well as the spinal nerves which exit the vertebral canal laterally between adjacent vertebrae.
Thoracic Spine
The thoracic spinal region, located inferiorly to the cervical spine, contains twelve vertebrae and spinal nerves. Vertebrae in this region are characterized by the presence of articulated ribs, connected to the vertebral body via synovial joints and the transverse process [1]. Movement in the thoracic spine is dictated by the vertical orientation of zygapophysial joints, facilitating transverse rotation, and limiting flexion and extension [1].
Lumbar Spine
Inferior to the thoracic region of the spinal column is the lumbar region. The lumbar spine supports the entire upper body, including the thorax and upper limbs and is responsible for transmitting loads to the pelvis and lower limbs. The five lumbar vertebrae are characterized by their large size and cylindrical vertebral body shape designed to support the upper body and absorb large axial compressive loads [1], [2]. A typical lumbar vertebra is shown in Figure 4. The spinal cord does not extend through the lumbar spine, although, the region also contains five lumbar spinal nerves. Curved surfaces of the zygapophysial joints in the lumbar spine facilitate flexion and extension through the lumbar region of the vertebral column [1].
Types of Injuries
Summary
Practice Problems
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Drake, Richard L.; Vogl, Wayne; Mitchell, Adam W. M.; Gray, Henry (2015). Gray’s Anatomy for Students, 3rd Edition. ISBN 9780702051319.
- ↑ Bogduk, Nikolai (2016). "Functional anatomy of the spine". Handbook of Clinical Neurology. 136: 675–688. doi:10.1016/B978-0-444-53486-6.00032-6.