These conditions are congenital abnormalities. Separation of S1 from the sacrum is termed вЂњlumbarisationвЂќ, while fusion of L5 to the sacrum is termed вЂњsacralisationвЂќ. Due to the lack of vertebral arches, there is no vertebral canal. It isВ recognisedВ by its lack of vertebral arches. The coccyxВ is a small bone which articulates with the apex of the sacrum. On the lateral walls of the sacrum are facets for articulation with the pelvis at the sacroiliac joints. It is described as an inverted triangle, with the apex pointing inferiorly. The sacrumВ is a collection of five fused vertebrae. Examples include epidural anaesthesia administration and lumbar puncture. Their size and orientation permits needle access to the spinal canal and spinal cord (which would not be possible between thoracic vertebrae). Their spinous processes are shorter than those of thoracic vertebrae and do not extend inferiorly below the level of the vertebral body. However, like the cervical vertebrae, they have a triangular-shaped vertebral foramen. They lack the characteristic features of other vertebrae, with no transverse foramina, costal facets, or bifid spinous processes. Lumbar vertebraeВ have very large vertebral bodies, which are kidney shaped. They are structurally specialised to support the weight of the torso. There are five lumbar vertebrae in most humans, which are the largestВ in the vertebral column. The articular processes are located at the intersection of the laminae and pedicles.ДЇig 6 вЂ“ Lateral view of a thoracic vertebrae. Articular processes вЂ“ form joints between one vertebra and its superior and inferior counterparts.

Lamina вЂ“В connect the transverse and spinous processes.PediclesВ вЂ“В connect the vertebral body to the transverse processes.In the thoracic vertebrae, the transverse processes articulate with the ribs. Transverse processes вЂ“ each vertebra has two transverse processes, which extend laterally and posteriorly from the vertebral body.Spinous processes вЂ“ each vertebra has a single spinous process, centred posteriorly at the point of the arch.The vertebral arches have several bonyВ prominences, which act as attachmentВ sites for muscles and ligaments: The foramina of all the vertebrae line up to form the vertebral canal, which encloses the spinal cord. In combination with the vertebral body, the vertebral arch forms an enclosed hole вЂ“ the vertebral foramen. The vertebral arch forms the lateral and posteriorВ aspect of each vertebrae. Fig 2 вЂ“ The general structure of a vertebrae.

Bones of the spine