The muscles of the lower back help stabilize, rotate, flex,
and extend the spinal column, a bony
tower of 24 vertebrae that gives the body structure and houses the spinal cord.
The spinal cord and its nerves are
the means by which the body and brain communicate. Together, the brain and
spinal cord make up the central nervous system.
The spine’s three sections, from top to bottom, are the
cervical (neck), thoracic (abdomen,) and lumbar (lower back). Throughout the
spine, intervertebral discs made of
cushioning material both pad and connect the vertebrae.
The lumbar spine includes:
- Lumbar
vertebrae: Numbered L1 through L5, these odd-shaped vertebrae signal the
end of the typical bones of the spinal column.
- Sacrum:
This triangle-shaped bone is made up of five fused vertebrae. It fits like a
wedge into the back of the pelvis at the hips.
- Coccyx:
This small bone is better known as the tailbone.
Muscles connect to the vertebrae and bones via ligaments,
flexible bands of fibrous tissue. The deep muscles of the back fit into or
affix parts of themselves to the grooves in the spinous process, or the protrusion
of the bone than can be felt through the skin.
Important muscles of the lumbar spine include:
- Multifidus:
This long muscle travels nearly the entire length of the back. It stabilizes and
rotates the lumbar spine.
- Longissimus:
Another long muscle, this one begins in the middle of the lumbar spine and
continues up to the TK.
- Spinalis:
This superficial muscle begins as a thick tendon from the sacrum and travels up
into the neck.
Lower back pain is a common ailment. This can arise for
reasons ranging from improper posture to a compression fracture. Lower back
issues can put pressure on the lumbar spine nerves and create even stronger
pain as the nerves become pinched or irritated from friction. Some common
causes of reoccurring lower back pain include:
- Muscle injury, which can occur from overuse or a
sudden injury
- Fractured vertebrae
- Herniated disc, or damage to the cushioning
between vertebrae
- Infection of the spinal cord, fluid, or discs
- Spinal stenosis, or narrowing of the spinal
canal
- Osteoarthritis, a
degenerative bone disease
