Back and Spine

Excessive curvature of the spine can occur as a result of postural changes associated with habitual activities of work or play, or can be secondary to abnormal spinal development. Scoliosis is a growth deformity of the spine that results in a fixed lateral curvature, torsion, and rotation of the vertebral column. (Hyper-) Kyphosis describes an abnormal increase in the primary convex curvature of the thoracic spine. (Hyper-)Lordosis is an exaggeration of the secondary concave curvature in the lumbar spine. [ L126 ]

Posterolateral disc herniations , spondylophytes , or tumors can lead to a narrowing of an intervertebral foramen and compression of the spinal nerve roots causing deficits in nerve function. [ L126 ]

Spinal stenosis refers to an abnormal narrowing of a (vertebral or intervertebral) foramen within the vertebral column that can lead to pressure on or compression of the spinal cord and spinal nerve roots. It is most commonly caused by wear-and-tear degenerative changes in the spine (e.g. osteoarthritis). Stenosis can lead to symptoms such as pain, numbness, paresthesia, and loss of motor control. The location of the stenosis will determine which area of the body is affected. Approximately 75 % of all spinal stenoses occur in the lumbar spine – leading to symptoms of sciatica (tingling, weakness, or numbness that radiates from the low back into the buttocks and legs). In severe cases, physicians may recommend surgery to create additional space for the spinal cord or nerves within the narrowed foramen.

[ E684 ]

Approximately 25 % of individuals under 40 years of age, and 60 % of people older than 40 years show some evidence of disc degeneration. Degenerative changes of an intervertebral disc are most frequently observed in the lumbar and cervical regions of the spine. It can result in disc protrusion or disc prolapse, with the disc tissue most commonly shifting to the posterior and lateral sides. This can lead to compression of the spinal nerves (radiculopathy) as they exit through the intervertebral foramen. The discs located between L4/L5 and L5/S1 are the most common areas of injury .

[ L127 ]

Plane of orientation of facet joints (a); spinal range of motion (b).

The facet joints in the lower cervical region are oriented 45° to the transverse plane and lie parallel to the frontal plane, with the superior articular processes facing posterior and up and the inferior articular processes facing anterior and down. This facilitates a large range of motion during flexion, extension, lateral flexion, and rotation. The facet joints between adjacent thoracic vertebrae are angled at 60° to the transverse plane and 20° to the frontal plane, with the superior facets facing posterolaterally (and a little upwards) and the inferior facets facing anteromedially (and slightly downwards). This facilitates the movements of lateral flexion and rotation, but allows only limited flexion and extension movements. The facet joints in the lumbar region are oriented at right angles (90°) to the transverse plane and 45° to the frontal plane. The superior facets face medially, and the inferior facets face laterally (this changes at the lumbosacral junction in order to keep the vertebral column stable on the sacrum). The orientation of the lumbar facets facilitates flexion and extension movements of the lumbar spine, but limits the ability of the region to rotate. [ L126 ]

The normal architecture of a healthy C-spine allows the neck to assume a naturally lordotic posture. This lordosis allows for controlled motion and transmission of forces to the supporting muscles and soft tissues. a When the neck is in flexion, the normal lordoctic position of the neck is lost, making it highly susceptible to injuries such as a cervical fracture and/or dislocation. b As the neck moves into an extended position, the size of the lordotic curve increases.

[ G724 ]