The lumbar vertebrae make up a part of the spine.
Position. The lumbar vertebrae form part of the spine, or spine, a bone structure located between the head and the pelvis. The spine forms the skeletal base of the trunk, located dorsally and along the midline. It starts under the skull and extends into the pelvic region (1). The spine is made up of an average of 33 bones, called vertebrae (2). These bones are linked together to form an axis, which has a double S shape. There are 5 of the lumbar vertebrae forming a curve facing forward (3). They make up the lumbar region in the lower back, and are located between the thoracic vertebrae and the sacrum. The lumbar vertebrae are named from L1 to L5.
Structure. Each lumbar vertebra has the same basic structure (1) (2):
- The body, the ventral part of the vertebra, is large and solid. It 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.
Joints and insertions. The lumbar vertebrae are connected to each other by ligaments. They also have several articular surfaces to ensure their mobility. Intervertebral discs, fibrocartilages comprising a nucleus, are located between the bodies of neighboring vertebrae (1) (2).
Musculature. The spine is covered by the back muscles.
Functions of the lumbar vertebrae
Support and protection role. Making up the spine, the lumbar vertebrae help support the head and protect the spinal cord.
Role in mobility and posture. Constituting the spine, the lumbar vertebrae make it possible to preserve the posture of the trunk and thus maintain the standing position. The structure of the vertebrae allows many movements such as torsion movements of the trunk, bending of the trunk or even traction.
Pathologies and associated issues
Dos disease. It is defined as a localized pain that begins most often in the spine and generally affects the muscle groups around it. Low back pain is localized pain in the lumbar region. Sciatica, characterized by pain starting in the lower back and extending into the leg. Frequent, they are due to compression of the sciatic nerve which can sometimes be caused by the lumbar vertebrae. Different pathologies can be at the origin of this pain (4):
- Degenerative pathologies. Osteoarthritis is characterized by the wear and tear of the cartilage protecting the bones of the joints. (5) 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.
- Deformities of the spine. Deformations of the column may occur. Scoliosis is a lateral displacement of the spine (6). Lordosis is associated with an accentuated arch in the lumbar vertebrae. (6)
- Lumbago. This pathology is due to deformations or tears of the ligaments or muscles located in the lumbar vertebrae.
Drug treatments. Depending on the pathology diagnosed, certain drugs may be prescribed as painkillers.
Physiotherapy. Back rehabilitation can be carried out with physiotherapy or osteopathy sessions.
Surgical treatment. Depending on the pathology diagnosed, surgery may be performed in the lumbar region.
Exploration and exams
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.
Research work. Researchers from an Inserm unit have apparently succeeded in transforming adipose stem cells into cells that can replace intervertebral discs. This work aims to renew the worn intervertebral discs, causing some back pain. (7)