The spine acts as the scaffolding for the entire body, allowing humans to stand upright(1). It consists of 24 bones called the vertebrae, which are separated by intervertebral discs(2)

The human spine supports roughly half the weight of the body(3).

Each vertebra is connected by groups of ligaments, which connect bones to other bones. Meanwhile, tendons connect the muscles to the bones(4)

The spinal column has facet joints that connect the vertebrae and provide them with the flexibility to move against each other(5).


The vertebrae serve as the building blocks of the whole spinal column. They protect and support the spinal cord while bearing most of the body’s weight(6)

Each vertebra’s body is a large and round portion of bone attached to a bony ring. When stacked on top of each other, the rings create a tube where the spinal cord is encased(7).

Like other bones, the vertebra has a hard and strong outer skin called cortical bone. Inside of the vertebra is a soft, spongy bone called cancellous bone(8).

The vertebrae can be divided into four regions(9):

Cervical Spine

The cervical spine includes the first seven vertebrae of the spine. It begins below the skull and ends above the thoracic spine(10).

The cervical spine has a backward C shape and is more flexible than other spinal groups(11).

Unlike other spinal groups, the cervical spine has openings in each vertebra for arteries that deliver blood to the brain.

Thoracic Spine

The thoracic region includes the middle 12 vertebrae of the spine. The thoracic spine’s vertebrae are linked to the ribs and form part of the back of the thorax (the area between the diaphragm and neck)(12)

The intervertebral discs are thin, so less movement is allowed between vertebrae in the thoracic spine than the lumbar or cervical regions(13).

The thoracic spine has a kyphotic shape or a regular C-shaped curve.

Lumbar Spine

The lumbar spine, which has five vertebrae, is located in the lower back(14).  

The vertebrae in the lumbar spine also support the weight of the upper body. The lumbar vertebrae absorb axial forces coming from the head, neck, and trunk(15).

The lumbar spine is connected to the pelvis, where most humans’ weight–bearing and body movements occur. Heavy activities may damage certain areas of the lumbar spine(16).

Sacrum and Coccyx Spine

The sacrum and coccyx region of the spine include the spine’s nine lowest vertebrae. The five sacral bones are convex, while the four bones in the coccyx (bones at the base of the spine) are concave(17).

Spinal Cord

The spinal cord refers to the long column of nerve fibers enclosed in the spinal canal. It is protected by a membrane known as the dura mater, which forms a watertight sack around the organ and its nerves(18).

The organ functions primarily in the transmission of signals between the brain and the rest of the body. However, the spinal cord also has neural circuits that control various reflexes and central pattern generators(19).

Intervertebral Disc

The intervertebral discs are flat, round discs that function as cushions between each vertebra in the spine(20)

Each intervertebral disc is encased in the annulus, a strong ring of fibers. The annulus, the strongest part of the disc, is a ligament that holds the vertebrae together(21).

Inside the discs are soft, jelly-like compounds called nucleus pulposus. The compounds serve as the discs’ primary shock absorber(21)

The nucleus pulposus is made up of moist tissue with high water content. The water in the nucleus helps the disc absorb impact(22).

Paraspinal Muscles

The paraspinal muscles are the muscles next to the spine. They support the spine and the spine’s motor movement(23).

Some back muscles also control a part of the movement between the spine and other bones in the body.

Paraspinal muscles may be injured directly, such as when they are pulled or strained. The muscles may also cause problems indirectly, such as when they spasm after a spinal injury(24).

Facet Joint

The facet joints are the knobs that connect each vertebra. Each vertebra has two facet joints, one on each side(25).

Also known as synovial joints, facet joints allow movement between two bones. Without facet joints, humans would not have flexibility in their spine(26).

The joints are surrounded by a watertight sack composed of soft tissue and ligaments. This sack serves as a protective capsule around the facet joint(27).

Causes of Spinal Pain

Below is a list of the causes of pain in the spine(28):

  • Irritation of the nerves as they exit the bones of the spine
  • Strain in the muscles on the back holding the spine upright
  • Damage to the bones, joints, or ligaments
  • Damage to intervertebral discs
  • Abnormal movement between the vertebrae
  • Tumors, trauma, deformity, infection, or other abnormalities in the spine


  1. Cedars-Sinai. Anatomy of the Spine. Retrieved from https://www.cedars-sinai.org/health-library/diseases-and-conditions/a/anatomy-of-the-spine.html
  2. Cornell University Ergonomics Web. Anatomy of the Spine. Retrieved from http://ergo.human.cornell.edu/DEA3250Flipbook/DEA3250notes/spine.html
  3. Cedars-Sinai. Op cit.
  4. University of Maryland Medical Center. A Patient’s Guide to Anatomy and Function of the Spine. Retrieved from https://www.umms.org/ummc/health-services/orthopedics/services/spine/patient-guides/anatomy-function?__cf_chl_jschl_tk__=c6d0b19a73019a0d8562e7d6e6fb0b2584619a65-1611209313-0-ASc-rSsSX6QqcEf257xIVnU0e65tjg8BKkTX9Rebt3SM41dBZZbyDh7Kw8_5ICblSImrEnPqutK4fLHkcg2TP1oCTd–FzR-wph58pUp-e70moDsasKEfSIGmu46NE1HxC8k0VrI1Rx40s0qFO-g7T7vSObHhvzBuRZKS30RG9InqEDOyDjvA2sCYLReWUj4_JoKrjtJHoWJdELl0StBH9ges1be8AE856cNM5YscjT6J-7u2fltaDFeLC3XfYJqr3Dzq5q4RpbQj8Jhf57yqRwzsP2NBgxM_ILKZYGr7iXlF3th5z9qrgrBzzft2vdiDyVY36vHwhqAMvo927aoh6nelJdibCaa8o1pUBXwi0i2HDwTF11aeSs4QGJJQS5IwYUYTS9wQzIU8pPrP-QBVfxxKIaju4RC878HNJJPSiAFOKzZ_IRFwOTR41R1RYCCqtphX6kxQk2dM0eaMOCitX2o-BfWirdKG7RTWImU40h_
  5. Ibid
  6. Ibid
  7. Ibid
  8. Ibid
  9. Cornell University Ergonomics Web. Op cit.
  10. University of Maryland Medical Center. Op cit.
  11. Ibid
  12. Ibid
  13. Ibid
  14. Ibid
  15. Sassack, B. & Carrier, J. (2020). Anatomy, Back, Lumbar Spine. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK557616/
  16. University of Maryland Medical Center. Op cit.
  17. Cornell University Ergonomics Web. Op cit.
  18. University of Maryland Medical Center. Op cit.
  19. Lumen Learning. The Spinal Cord. Retrieved from https://courses.lumenlearning.com/boundless-ap/chapter/the-spinal-cord/
  20. University of Maryland Medical Center. Op cit.
  21. Ibid
  22. Ibid
  23. Ibid
  24. Ibid
  25. Ibid
  26. Ibid
  27. Ibid
  28. Cedars-Sinai. Op cit.

CT Scan of the Cervical Spine

The images below are reconstructions obtained from a scan of the cervical spine. Each row of three thumbnails correspond to a given level and the green cross indicates the reference planes for each image of this Level. Clinicians use a computed tomography (CT) scan to diagnose a particular disorder or disease and detect tumors, […]

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Lumbar Spine Computed Tomography

The images below are reconstructions obtained from a scan of lumbar spine. Each row of three thumbnails correspond to a given level and the green cross indicates the reference planes for each image of this Level. Computed tomography (CT) is a proven method for evaluating the lumbar spine. This imaging modality provides great bone

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Cervical Spine MRI Anatomy

This photo gallery presents the anatomical structures found on cervical spine MRI (T2-weighted axial and sagittal views). Axial view Sagittal view Axial view Image 1. MRI of the Cervical Spine, axial T2-weighted image. 1, Jugular vein and Carotid artery. 2, Nerve root. 3, Lamina. 4, Spinal cord. 5, Intervertebral foramen. 6, Inferior endplate, C2.

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The Anatomy of the Spinal Cord

This webpage presents the anatomical structures found on spinal canal. The Spinal Cord and Its Functions The brain and spinal cord are part of the central nervous system (CNS)(1). The CNS is responsible for bodily functions, such as motor skills, sensory responses, and cognitive functions(2). There are three specific spinal cord functions: motor, sensation,

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Sacrum and Coccyx Anatomy

This photo gallery presents the anatomy of sacrum and coccyx by means of 3D-reconstructions, axial, sagittal and coronal reconstructions obtained from a scan of pelvis. Sacrum The sacrum refers to the bony structure located at the base of the lumbar vertebrae. It forms the posterior pelvic wall(1). The sacrum helps strengthen and stabilize the

Sacrum and Coccyx Anatomy Read More

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