The spine, also called the spine, is a bone structure located between the head and the pelvis.

Structure of the spine

The spine is made up of an average of 33 bones, called vertebrae. These bones are linked together to form an axis, which has a double S shape. From the upper part to the lower part, these 33 vertebrae are defined according to their location (2):

• 7 cervical vertebrae
• 12 thoracic vertebrae
• 5 lumbar vertebrae
• 5 sacral vertebrae fused together to form the sacrum
• 4 coccygeal vertebrae fused together to form the coccyx

Being flexible and mobile, the first 24 vertebrae are considered the true vertebrae while the sacrum and coccyx, remaining fixed, are considered the false vertebrae.

Structure of the vertebrae

Each vertebra has the same basic constitution (1) (2).

• The body, the ventral part of the vertebra, is large and solid. She carries the weight of the skeletal axis
• The vertebral arch, the dorsal part of the vertebra, surrounds the vertebral foramen.
• The vertebral foramen is the central, hollowed-out part of the vertebra. The stack of vertebrae and foramina constitutes the vertebral canal, crossed by the spinal cord.

Musculature

The spine is covered by the back muscles.

Support and protection role. The spine gives the back a role of supporting the head and protecting the spinal cord.

Role in mobility and posture. The spine helps to preserve the posture of the trunk and thus maintain the standing position. The structure of the spine allows many movements such as torsion movements of the trunk, bending of the trunk or even traction.

Back pain is defined as localized pain that begins most often in the spine and generally affects the muscle groups around it. According to their origin Three main forms are distinguished: neck pain, the dorsalgies and low back pain. sciatic, characterized by pain starting in the lower back and extending into the leg, are also common and are due to compression of the sciatic nerve. Different pathologies can be at the origin of these pains. (3)

• Degenerative pathologies. Different pathologies can lead to the progressive degradation of cellular elements. Osteoarthritis is characterized by the wear and tear of the cartilage protecting the bones of the joints. (4) The herniated disc corresponds to the expulsion behind the nucleus of the intervertebral disc, by wear of the latter. This can result in compression of the spinal cord or sciatic nerve.
• Deformation of the spine. Different deformation of the column may appear. Scoliosis is a lateral displacement of the column5. Kyphosis develops with an excessive curvature of the back at shoulder height while lordosis is associated with an accentuated arch in the lower back. (5)
• Lumbago and stiff neck. These pathologies are due to deformations or tears in the ligaments or muscles, located respectively in the lumbar region or in the cervical region.

Drug treatments. Depending on the pathology, certain drugs may be prescribed, including painkillers.

Physiotherapye. Back rehabilitation can be carried out with physiotherapy or osteopathy sessions.

Surgical treatment. Depending on the pathology, a surgical intervention may be performed on the back.

Physical examination. The doctor’s observation of the back posture is the first step in identifying an abnormality.

Radiological examinations. Depending on the suspected or proven pathology, additional examinations may be performed such as an X-ray, an ultrasound, a CT scan, an MRI or a scintigraphy.

Published in the scientific journal Stem Cell, researchers from an Inserm unit have succeeded in transforming adipose stem cells into cells that can replace intervertebral discs. This work aims to renew the worn intervertebral discs, causing some of the lower back pain. (6)