Spine: The column of bones (vertebrae) protecting the spinal cord
Introduction: The spine is a column of 26 bones that extend in a line from the base of the skull to the pelvis (see fig. 1 ). Twenty-four of the bones are called vertebrae. The bones of the spine include 7 cervical vertebrae in the neck; 12 thoracic vertebrae at the back wall of the chest; 5 lumbar vertebrae at the inward curve (small) of the lower back; the sacrum, composed of 5 fused vertebrae between the hip bones; and the coccyx, composed of 3 to 5 fused bones at the lower tip of the vertebral column. The vertebrae link to each other and are cushioned by shock-absorbing disks that lie between them.
The vertebral column provides the main support for the upper body, allowing humans to stand upright or bend and twist, and it protects the spinal cord from injury. Following are structures of the spine most involved in spinal stenosis.
Intervertebral disks--pads of cartilage between vertebrae that act as shock absorbers.
Facet joints--joints located on both sides and on the top and bottom of each vertebra. They connect the vertebrae to each other and permit back motion.
Intervertebral foramen (also called neural foramen)--an opening between vertebrae through which nerves leave the spine and extend to other parts of the body.
Lamina--part of the vertebra at the upper portion of the vertebral arch that forms the roof of the canal through which the spinal cord and nerve roots pass.
Ligaments--elastic bands of tissue that support the spine by preventing the vertebrae from slipping out of line as the spine moves. A large ligament often involved in spinal stenosis is the ligamentum flavum, which runs as a continuous band from lamina to lamina in the spine.
Pedicles--narrow stem-like structures on the vertebrae that form the walls of the bottom part of the vertebral arch.
Spinal cord/nerve roots--a major part of the central nervous system that extends from the base of the brain down to the lower back and that is encased by the vertebral column. It consists of nerve cells and bundles of nerves. The cord connects the brain to all parts of the body via 31 pairs of nerves that branch out from the cord and leave the spine between vertebrae (see fig. 2 ).
Synovium--a thin membrane that produces fluid to lubricate the facet joints, allowing them to move easily.
Vertebral arch--a circle of bone around the canal through which the spinal cord passes. It is composed of a floor at the back of the vertebra, walls (the pedicles), and a ceiling where two laminae join.1
Stacked on top of one another in the spine are more than 30 bones, the vertebrae, which together form the spine. They are divided into four regions:
- the seven cervical or neck vertebrae (labeled C1-C7),
- the 12 thoracic or upper back vertebrae (labeled T1-T12),
- the five lumbar vertebrae (labeled L1-L5), which we know as the lower back, and
- the sacrum and coccyx, a group of bones fused together at the base of the spine.
The vertebrae are linked by ligaments, tendons, and muscles. Back pain can occur when, for example, someone lifts something too heavy, causing a sprain, pull, strain, or spasm in one of these muscles or ligaments in the back.
Between the vertebrae are round, spongy pads of cartilage called discs that act much like shock absorbers. In many cases, degeneration or pressure from overexertion can cause a disc to shift or protrude and bulge, causing pressure on a nerve and resultant pain. When this happens, the condition is called a slipped, bulging, herniated, or ruptured disc, and it sometimes results in permanent nerve damage.
The column-like spinal cord is divided into segments similar to the corresponding vertebrae: cervical, thoracic, lumbar, sacral, and coccygeal. The cord also has nerve roots and rootlets which form branch-like appendages leading from its ventral side (that is, the front of the body) and from its dorsal side (that is, the back of the body). Along the dorsal root are the cells of the dorsal root ganglia, which are critical in the transmission of "pain" messages from the cord to the brain. It is here where injury, damage, and trauma become pain.2
Condition count: 52 ; see list below.
Organ subtypes: spinal cord (22), cervical vertebrae (0), thoracic vertebrae (0), lumbar vertebrae (0)
Organ types: Back (56), Bone (91)
Number: 1 spine
Main condition: spine conditions
Organs: all organs
Diseases list: The following list of medical conditions have 'Spine' or similar listed as an affected body part in our database:
- Acute Disseminated Encephalomyelitis ... spinal cord
- Adrenoleukodystrophy ... spinal cord
- Adult SMA ... spine
- Adult-onset ALD ... spinal cord
- Alexander Syndrome ... spinal cord
- Anencephaly ... spinal cord
- Ankylosing Spondylitis ... spine
- Arthritis ... spine
- Brown-Sequard Syndrome ... spinal cord
- Classic childhood ALD ... spinal cord
- Demyelinating disorder ... spine
- Disc Disorders ... spine
- Dislocation ... spine
- Female carrier ALD ... spinal cord
- Friedreich's ataxia ... spinal cord
- Herniated disc ... spine
- Klippel Feil Syndrome ... spine
- Kyphosis ... spine
- Leukodystrophy ... spinal cord
- Lordosis ... spine
- Metachromatic Leukodystrophy ... spinal cord
- Multiple Sclerosis ... spinal cord
- Myelitis ... spinal cord
- Neural tube defect ... spinal cord
- Osteoarthritis ... spine
- Osteomyelitis ... spine
- Paget's disease of bone ... spine
- Progressive Spinobulbar muscular atrophy ... spine
- Reiterís syndrome ... spine
- Scheuermann's disease ... spine, vertebrae
- Sciatica ... spine
- Scoliosis ... spine
- Seronegative spondyloarthropathy ... spine
- Spina bifida ... spinal cord
- Spinal conditions ... spine
- Spinal Cord Disorders ... spinal cord
- Spinal cord injury ... spinal cord, spine
- Spinal Cord Tumor ... spinal cord
- Spinal curvature ... spine, vertebrae
- Spinal Muscular Atrophy ... spine
- Spinal Muscular Atrophy type I ... spine
- Spinal Muscular Atrophy type II ... spine
- Spinal Muscular Atrophy type III ... spine
- Spinal stenosis ... spine
- Spondylitis ... spine
- Spondylosis ... spine
- Subacute combined degeneration of the spinal cord ... spinal cord
- Syringomyelia ... spinal cord
- Tethered Spinal Cord Syndrome ... spinal cord
- Transverse myelitis ... spinal cord
- Tuberculosis ... spine
- Vertebral fracture ... spine
1. excerpt from Questions and Answers About Spinal Stenosis: NIAMS
2. excerpt from Pain - Hope Through Research: NINDS
Medical Tools & Articles:
- Risk Factor Center
- Medical Statistics Center
- Medical Treatment Center
- Prevention Center
- Medical Tests Center