lumbar vertebrae

vertebra /ver·te·bra/ (ver´tĕ-brah) pl. ver´tebrae   [L.] any of the 33 bones of the vertebral (spinal) column, comprising 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae .ver´tebral

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basilar vertebra  the lowest lumbar vertebra.

cervical vertebrae  the seven vertebrae closest to the skull, constituting the skeleton of the neck. Symbols C1–C7.

coccygeal vertebrae  the three to five rudimentary segments of the vertebral column most distant from the skull, which fuse to form the coccyx.

cranial vertebrae  the segments of the skull and facial bones, regarded by some as modified vertebrae.

dorsal vertebrae  thoracic vertebrae.

false vertebrae  those vertebrae which normally fuse with adjoining segments; the sacral and coccygeal vertebrae.

lumbar vertebrae  the five segments of the vertebral column between the twelfth thoracic vertebra and the sacrum. Symbols L1–L5.

odontoid vertebra  the second cervical vertebra (axis).

vertebra pla´na  a condition of spondylitis in which the body of the vertebra is reduced to a sclerotic disk.

sacral vertebrae  the segments (usually five) below the lumbar vertebrae, which normally fuse to form the sacrum. Symbols S1–S5.

sternal vertebra  sternebra.

thoracic vertebrae  the 12 segments of the vertebral column between the cervical and the lumbar vertebrae, giving attachment to the ribs and forming part of the posterior wall of the thorax. Symbols T1–T12.

true vertebrae  those segments of the vertebral column that normally remain unfused throughout life: the cervical, thoracic, and lumbar vertebrae.

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Lumbar vertebrae

The vertebrae of the lower back below the level of the ribs.

Mentioned in: Spinal Instrumentation

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vertebra [ver´tĕ-brah] (L.)

any of the separate segments comprising the spine (vertebral column). The vertebrae support the body and provide the protective bony corridor (the spinal or vertebral canal) through which the spinal cord passes. The 33 bones that make up the spine differ considerably in size and structure according to location. There are seven cervical (neck) vertebrae, 12 thoracic (high back), five lumbar (low back), five sacral (near the base of the spine), and four coccygeal (at the base). The five sacral vertebrae are fused to form the sacrum, and the four coccygeal vertebrae are fused to form the coccyx.



The weight-bearing portion of a typical vertebra is the vertebral body, the most forward portion. This is a cylindrical structure that is separated from the vertebral bodies above and below by disks of cartilage and fibrous tissue. These intervertebral disks act as cushions to absorb the mechanical shock of walking, running, and other activity. Sometimes rupture or herniation of a disk may occur (see herniated disk).

A semicircular arch of bone (the vertebral arch) protrudes from the back of each vertebral body, surrounding the spinal cord. Directly in its midline a bony projection, the spinous process, grows backward from the arch. The spinous process can be felt on the back as a hard knob. Three pairs of outgrowths project from the arch. One of these protrudes horizontally on each side and in the thorax connects with the ribs. The remaining two form joints with the vertebrae above and below. The joints permit the spine to bend flexibly. The vertebrae are held firmly in place by a series of strong ligaments.

Structure of vertebrae.

cervical vertebrae the upper seven vertebrae, constituting the skeleton of the neck.

coccygeal vertebrae the lowest segments of the vertebral column, comprising three to five rudimentary vertebrae that form the coccyx.

cranial vertebra the segments of the skull and facial bones, regarded by some as modified vertebrae.

vertebra denta´ta the second cervical vertebra, or axis.

dorsal vertebrae thoracic vertebrae.

false vertebrae those vertebrae that normally fuse with adjoining segments: the sacral and coccygeal vertebrae.

lumbar vertebrae the five vertebrae between the thoracic vertebrae and the sacrum.

vertebra mag´na the sacrum.

odontoid vertebra the second cervical vertebra, or axis.

vertebra pla´na a condition of spondylitis in which the body of the vertebra is reduced to a sclerotic disk.

sacral vertebrae the vertebrae just below the lumbar vertebrae, usually five in number and fused to form the sacrum.

thoracic vertebrae the twelve vertebrae between the cervical and lumbar vertebrae, giving attachment to the ribs and forming part of the posterior wall of the thorax.

true vertebrae those segments of the vertebral column that normally remain unfused throughout life: the cervical, thoracic, and lumbar vertebrae.

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lumbar

pertaining to the loins.

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lumbar epidural analgesia

see epidural anesthesia.

lumbar paralysis

paraplegia generally and specifically that due to cerebrospinal nematodiasis.

lumbar plexus

one formed by the ventral branches of the last four or five lumbar nerves in the psoas major muscle.

lumbar puncture

insertion of a needle and stylet into the subarachnoid space between the seventh lumbar vertebra and sacrum in most species except the dog, where the space between the sixth and seventh lumbar vertebrae is usually used; called also spinal puncture. A lumbar puncture may be done to measure the pressure of cerebrospinal fluid and obtain a specimen for examination, and to inject a contrast medium for special radiographic examinations such as myelography. As a therapeutic measure it is sometimes done to relieve intracranial pressure or to remove blood or pus from the subarachnoid space. A lumbar puncture also is necessary for injection of a spinal anesthetic.

lumbar spinal stenosis

see lumbosacral stenosis.

lumbar tap

see lumbar puncture (above).

lumbar vertebrae

the vertebrae between the thoracic vertebrae and the sacrum, numbering seven in dogs and cats, six in horses and cattle, and six or seven in sheep and pigs.