CorpusHuman Anatomy
SkeletalBone

Typical vertebra

Vertebra

Also known as: vertebrae, vertebral body, vertebral arch, pedicle, lamina, spinous process, transverse process

The basic unit of the vertebral column: an anterior weight-bearing body and a posterior vertebral arch that encloses the vertebral foramen and carries seven processes.

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Overview

The vertebral body is a short cylinder of spongy bone with a thin cortical shell, bearing the weight of the trunk; its superior and inferior surfaces carry the cartilaginous end plates of the discs and an outer ring (ring apophysis). The vertebral arch consists of two pedicles (short stout bars projecting back from the body) and two flat laminae that meet in the midline. Body and arch enclose the vertebral foramen.

Seven processes arise from the arch: one spinous process (posteriorly, from the junction of the laminae), two transverse processes (from the pedicle–lamina junction) — both levers for muscles — and two superior and two inferior articular processes bearing facets that form the zygapophysial (facet) joints with adjacent vertebrae. The pars interarticularis is the part of the lamina between superior and inferior articular processes.

The superior and inferior vertebral notches of adjacent pedicles form the intervertebral foramina, bounded also by the disc and facet joint, through which spinal nerves and the dorsal root ganglia pass. Regional variations (cervical, thoracic, lumbar) are recognisable from the shape of the body, the vertebral foramen, the transverse processes and the orientation of the facets.

Location

Repeated segmental units of the vertebral column.

Parts & subdivisions

  1. Vertebral body
    Anterior weight-bearing cylinder of spongy bone.
  2. Pedicles
    Connect the arch to the body; notched above and below.
  3. Laminae
    Flat plates forming the posterior arch; removed in laminectomy.
  4. Spinous process
    Posterior midline lever; palpable along the back.
  5. Transverse processes
    Lateral levers for muscles; articulate with ribs in the thoracic region.
  6. Superior and inferior articular processes
    Bear the facets of the zygapophysial joints.
  7. Pars interarticularis
    Bony bridge between the articular processes; site of stress fracture (spondylolysis).
  8. Vertebral foramen
    Space for the spinal cord, meninges and epidural fat.
  9. Intervertebral foramen
    Formed by adjacent vertebral notches; transmits spinal nerve and dorsal root ganglion.

Anatomy

Ossification

Three primary centres at ≈8 weeks — one for the centrum and one for each half of the neural arch; the halves of the arch fuse ≈1 year, arch and centrum ≈3–6 years. Five secondary centres at puberty (tip of the spinous process, two transverse process tips, two ring apophyses) fuse by ≈25 years.

Function

  • Bears and transmits body weight (body)
  • Protects the spinal cord (arch)
  • Provides levers and attachments for back muscles and ligaments (processes)
  • Guides and limits intervertebral movement (articular processes)

Clinical significance

Spondylolysis and spondylolisthesis

A stress fracture of the pars interarticularis ("collar on the Scottie dog" on oblique X-ray), most often L5 in young athletes (gymnasts, bowlers); bilateral defects allow the vertebral body to slip forward (spondylolisthesis), commonly L5 on S1.

Spina bifida

Failure of fusion of the vertebral arches, most often lumbosacral: occulta (tuft of hair, dimple), meningocele or myelomeningocele (with neural tube defect; reduced by periconceptional folic acid).

Vertebral metastases

Red-marrow-rich vertebral bodies are the commonest site of skeletal metastases (breast, prostate, lung, kidney, thyroid); pedicle destruction gives the "winking owl" sign on AP X-ray.

Test yourself

Which feature is unique to cervical vertebrae?
  1. Costal facets on the transverse processes
  2. Foramina in the transverse processes
  3. Mammillary processes
  4. Sagittally oriented articular facets

Answer: Foramina in the transverse processes

Transverse foramina (foramina transversaria) are found only in cervical vertebrae; they transmit the vertebral artery (usually from C6 upward) and veins. Costal facets characterise thoracic vertebrae; mammillary processes and sagittal facets are lumbar features.

Which pair correctly matches the vertebra with its feature?
  1. Atlas — dens (odontoid process)
  2. Axis — no vertebral body
  3. C7 — vertebra prominens with a long non-bifid spinous process
  4. L5 — transverse foramina for the vertebral artery

Answer: C7 — vertebra prominens with a long non-bifid spinous process

C7 (vertebra prominens) has a long, palpable, non-bifid spinous process. The dens belongs to the axis (C2); it is the atlas (C1) that lacks a body. Lumbar vertebrae have no transverse foramina.

More skeletal system questions

Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.