What Constitutes the Lumbar Spine
The lumbar backbone is the third and lowest part of the spinal column, comprising 5 lumbar vertebrae, L1-L5. Situated in the lower back, it upholds the body’s mass and offers suppleness and motion. These are the most massive among all the vertebrae present in the spine.
Where Can the Lumbar Vertebrae be Found
They inhabit the lower back, commencing from the 12th thoracic spine and stretching to the sacrum.
Brief Information
| Type | Irregular bones |
| Quantity in the human body | 5 |
| Connects with | Each other, and with the pelvis |
Roles
Upholding Body’s Mass: The lumbar vertebrae uphold the upper two parts of the vertebral column — the cervical and thoracic vertebrae — and the head. Consequently, it is accountable for sustaining the complete body’s mass, and disseminating the mass from the upper body to the legs. It is also the segment of the vertebral column liable for supporting the weight when you hoist or carry any object.
Facilitating Movement: It links the upper body to the pelvis and permits bodily movements like bending, rotation, and flexing the lower back. L4 and L5 are predominantly responsible for these actions.
Sheltering the Spinal Cord and Nerves: The spinal cord, which commences at the base of the skull, culminates here in the lumbar spine, precisely at L1. The lumbar vertebrae provide a protective enclosure for all the spinal nerve roots (cauda equina) at the end of the spinal cord. These nerves then extend into the legs and feet to control movement and sensation.
Structure
These are the most massive and robust of all the vertebrae, with the individual bones possessing a typical structure.
Every vertebra possesses a thick, kidney-shaped vertebral body and a vertebral arch. A pair of pedicles and laminae from each arch arises on both sides, enclosing the triangular vertebral foramen.
In a quadrilateral bony protrusion, the spinous process arises from the middle of the vertebral arch, projecting backward and downward. The bony wing-like projections on either side of the spinous process are called the transverse processes. Several spinal muscles attach to the spinous and transverse processes.
There are accessory processes on the posterior side of the base of each transverse process. Two bony projections, the superior and inferior articular processes arise from both sides of the arch, bearing their corresponding facets, the superior and inferior articular facet). The mammillary processes arising from the lateral side of the superior articular processes is one unique feature of the lumbar vertebrae.
Connections
- Intervertebral symphyses: The facet joints between the individual vertebra through intervertebral discs
- Lumbosacral Joint: The joint formed between the fifth lumbar vertebra (L5) and the first sacral segment (C1).
Attachments of Muscles and Ligaments
Muscles attached
- Erector spinae
- Interspinales
- Intertransversarii
- Latissimus dorsi
- Rotatores
- Serratus (posterior and inferior)
Ligaments attached
- Ligamenta flava
- Anterior longitudinal ligament
- Posterior longitudinal ligament
- Intratransverse ligament
- Interspinous ligament
- Nuchal ligament
- Supraspinous ligament
- Facet capsular ligament
Questions and Answers
Q.1. Do some people have an additional lumbar vertebra?
Ans. Despite being uncommon, about 10% of individuals have a 6th lumbar vertebra in their lumbar spine. Although it frequently goes unnoticed and causes no difficulties, it can complicate the situation in the event of a spinal cord injury.
References
- The Lumbar Spine — Teachmeanatomy.info
- Lumbar Vertebrae — Physio-pedia.com
- Anatomy, Back, Lumbar Vertebrae — Pubmed.ncbi.nlm.nih.gov
- Lumbar Vertebrae — Sciencedirect.com
- Lumbar Vertebrae — Innerbody.com
