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The vertebral column is the main part of the axial skeleton which forms the central axis of the skeleton.  Its main function is for the protection of the spinal cord and for the transmission of body weight from the head, trunk and upper limbs, through the pelvic girdle to the lower limbs. It is made up of on average 33 vertebrae which are united by intervertebral discs (cartilaginous joints) and ligaments. 24 of the vertebrae are discrete bones while the last 9 are fused together in the sacrum and coccyx. There are 5 groups of vertebrae which make up the column each with variation that contributes to their function in the column; cervical (7), thoracic (12), lumbar (5), sacral (5), coccygeal (4). 

Gross Anatomy

·       Development

The formation of the vertebral column begins in the 4th week of foetal development. Mesenchymal cells known as sclerotomes form condensations around the notochord to create a neural tube and form the basis of vertebral body and two neural arches. These mesenchymal masses chondrify and become cartilaginous vertebrae. This results in three primary ossification sites, one in the body and one in each arch by the end of the 8th week of development. At birth, there are 3 discrete bony parts united by hyaline cartilage which eventually begin fusing within the 1st year of life, first in the lumbar region followed by the thoracic and cervical region reaching completion in the 6th year of life


Five secondary ossification centres develop during puberty in a typical vertebra: one at the tip of the spinous process, one at the tips of each transverse process, and one at the superior and inferior edges of the vertebral body known as the anular epiphyses. Ossification is complete around age 25. Exceptions to the typical pattern of ossification include C1, C2 and the sacrum and coccyx.


During fetal development, the column is curved in a gentle c shape, which makes the primary curves, the thoracic and sacral curvatures, however the secondary curvatures develop after birth, with the cervical lordosis forming as an infant begins to lift their head and the lumbar lordosis as they begin to walk.


·       Macro-anatomy (e.g. surfaces, ridges, named areas)

A “typical” vertebra consists of two main parts, the vertebral body and the vertebral arches, which surround the vertebral canal providing the protection for the spinal cord


Vertebral Body

The vertebral body bears the major part of the weight transmitted through the column. It is short and cylindrical, articulating with the body of the adjacent vertebral body via strong intervertebral discs. It is made of a thin shell of cortical bone surrounded by a core of porous cancellous bone. The horizontal and vertical trabeculae pattern in the vertebral resists the compressive forces which act on the body of the vertebrae.


Neural Arch

Each arch consists of paired pedicles and lamina, a spinous process, lateral transverse processes and two superior and two inferior articular facets. Short, rounded pedicles arise from the posterolateral aspect of the body on either side. These support flat lamina that meets its opposite posteriorly in the midline to form the spinous process. The transverse processes arise from near the junction of the pedicles and laminae along with paired superior and inferior articular processes. The tips of the spinous processes of each arch may be palpable posteriorly in the midline with C7 being the most prominent.


·       Articulations (joints the bone is part of)

o   Intervertebral Joints - The vertebrae articulate with its adjacent neighbour via both its vertebral body and arch.  Each body on its superior and inferior aspect has a flat surface covered by hyaline cartilage and united by a thick fibrocartilaginous intervertebral disc.

o   Facet Joints or Zygapophysial joints - The neural arches articulate via the paired superior and inferior articular processes as synovial joints which allow a small degree of movement in the vertebral column. Synovial joints with a  thin joint capsule which allow gliding movements between the articular processes. The shape and disposition of the articular processes vary depending on the vertebral column region allowing for different types of movement

The different regions of the vertebral column also articulate with other parts of the axial skeleton, e.g. the skull in the cervical region, the rib cage in the thoracic region, the pelvis in the sacral region.

·       Blood Supply

The vertebral column is supplied by periosteal and equatorial branches of the segmental spinal arteries and their spinal branches. There are 31 paired branches which provide blood supply to the vertebral column. These arise from the subclavian and vertebral arteries in the cervical region, the aorta in the thoracic and lumbar region, and internal iliac artery in the sacral region.

The vertebrae are encircled on three sides by the paired segmental artery, with the equatorial branches supplying the vertebral body, and the posterior branches supplying the vertebral arches and muscles of the back and the spinal branches supplying the vertebral canal. The spinal branches enter via the intervertebral foramina to supply the periosteum, ligaments, and meninges of the epidural space, with the radicular medullar branches supplying the nervous tissue

The venous drainage of the vertebrae is into the internal and external vertebral venous plexuses which drain into the internal iliac, lumbar, azygos and basivertebral veins.



·       Nerve Supply

The vertebral column is mainly innervated by (recurrent) meningeal branches of the spinal nerves. These arise from the mixed spinal nerve. The mixed spinal nerve is present prior to the nerve exiting the spinal canal and splits into the anterior and posterior rami.  The recurrent meningeal nerves are the first branches from the spinal nerves and provide localising pain sensation particularly in acute intervertebral disc herniation and fractures.

The facet (zygapophysial)  joints are supplied by the articular branches of the medial branches of the posterior rami of the corresponding spinal nerve and the two adjacent spinal roots.

 The intervertebral discs and related ligaments are supplied by a number of branches of the ventral rami of the spinal nerve and sympathetic nervous system. Although the spinal cord terminates at the level of the L1/L2 vertebral body, the spinal nerves for each segment exit the vertebral canal at their corresponding level.


·       Ligamentous attachments

The stability of the vertebral column is dependent on the ligaments running along its length. The vertebral bodies are united by the anterior and posterior longitudinal ligaments.

The anterior longitudinal ligament runs from the occiput to the sacrum on the anterior aspect of the vertebral body while the posterior from the axis (C2) to the sacrum on the posterior aspect of the bodies.

Additional support is provided posteriorly by the ligamentum flavum and the supraspinous, interspinous and intertransverse ligaments.

The ligamentum flavum contains a large amount of yellow elastic tissue and unites adjacent laminae. It is strong and maintains the curvature of the vertebral column and provides support when it is flexed.

The supraspinous, interspinsous and intertransverse ligaments help unite adjacent vertebra by attaching to the spinous processes (supraspinous and interspinous ligaments) and the transverse processes (intertransverse ligaments).  

Clinical Anatomy

Spina Bifida

Spina Bifida is a congenital disorder which results from the failure of the neural arch of the vertebral column to close adequately. It commonly affects the lumbar region of the back and if severe enough can cause the contents of the vertebral canal to protrude.  If the protrusion is just though the defect and skin is intact, it is a meningocele. If there is protrusion of the spinal cord and meninges through the defect and skin, it is known as a myelomeningocele and can be associated to severe disability. However if there is no cord protrusion it is known as Spina bifida occulta. Upto 5% of the population are thought to have occulta and can often be identified by a hairy dimple in the affected area.



Kyphosis is a form of spinal disease which results in abnormal concave shaping of the vertebral column in the thoracic region. This is also be known as hyperkyphosis and the resulting deformity is often called “Kelso’s hunchback”. It occurs most commonly due to osteoporosis and arthritis, although congenital conditions such as Scheuermann’s disease can cause structural kyphosis.



Scoliosis is lateral curvature of the spine and is the most common spinal disease affecting upto 0.5% of the population. It is most common in females and may result in unequal growth of the side of the vertebra leading to lack of fusion. It can be congenital, idiopathic or secondary to conditions such as cerebral palsy or spina bifida.



Lordosis is the excessive convex shape of the vertebral column in the lumbar region, also known as lumbar hyperlordosis or “swayback”. It can often be a cause of lower back pain, and has a range of causes including tight lumbar muscles, pregnancy, vitamin D deficiency in children.



Spondylolisthesis is the forward displacement of a vertebra. It occurs most frequently at L5 . The most common cause if a fracture or congenital defect of the pars interarticularis of the neural arch. Backward displacement of a vertebra is known as retrolisthesis.


Compression Fractures

The commonest type of vertebral fracture is flexion compression fracture which typically occurs at T12 and / or L1. This can result in “wedging” of the affected vertebral body and in the majority of patients, the posterior longitudinal ligament remains intact meaning the fracture is stable. However if there is also forcible rotation with severe flexion, the ligamentum flavum and interspinous ligaments can be ruptured resulting in spinal cord compression.

Compression fractures are common in the elderly population particularly in those who have osteoporosis. This is because osteoporosis reduces the bone density of cancellous bone leaving the defects in the trabecula pattern of the vertebral body.

Quick Anatomy

Key Facts




Ligmentum Flavum

Connect all lamina from C2 to sacrum on inner surface of lamina

Preserve vertebral column alignment – maintain upright posture

Supraspinous ligament

Connects the tips of the spinous processes from C7 to sacrum.

Limit hyperflexion

Interspinous Ligaments

Connect the root of one spinous process to the apex of each spinous process

Limit flexion

Intertransverse Ligaments

Attach to length of transverse processes to the transverse process below.

Limit lateral flexion

Anterior Longitudinal Ligament

Down anterior surface of all vertebral bodies and intervertebral discs. From the occiput to the sacrum

Prevent hyperextension

Posterior Longitudinal Ligament

Down posterior surface of all vertebral bodies and intervertebral discs. From the axis (C2) to the sacrum

Prevent hyperflexion


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The primary function of the vertebrae and the vertebral column is to protect the spinal cord and provide support for the skeleton by transmitting forces down through the legs, while allowing some movement of the axial skeleton. The irregular shape of each vertebra allow the two main parts of the vertebra, the body and neural arch to carry out these functions. The 33 vertebrae form around 70cm of vertebral column with the vertebral bodies of the column enlarging in size until L5 at the lumbosacral junction. This is due to the need for increased load bearing until the weight is distributed to the pelvic girdle and sacrum at the lumbosacral junction. Stability of the vertebral column is dependent on its arrangement, articulation, ligaments and surrounding muscles and often vertebral column pathology and back conditions is often due to dysfunction one of these components causing increased stress on the other aspects. 


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