Cervical vertebrae are seven in number. The first, second, and
seventh are modified (or) atypical vertebrae.
They have large vertebral foramen to accommodate the
cervical swelling of the medulla. All cervical vertebrae have a foramen in
the each side of the transverse process known as Foramen Trasversorium
through which vertebral artery, vein and plexus of nerves are transmitted.
The body of the vertebrae is oval and its superior surface is
concave from side to side.
These are short in size and projects upwards and backwards from
the middle of posterolateral parts of body and then from the
posteromedial wall of the foramen transversorium.
These are long and rectangular and almost overlap their neighbours
These are short and bifid.
These are the oblique cut ends of short bone, the articular process
lying at the junction of pedicle and laminae on each side. The superior
facet faces upwards and backwards, the inferior facet faces downwards
It is large and triangular in shape.
Each transverse process is short and perforated by the foramen
transversorium. The costal process projects laterally from the body.
Behind the transverse foramen, the true transverse process lies laterally
from the junction of pedicle and laminae to end in posterior tubercle.
Atypical Cervical Vertebrae
It supports the globe of head. It has no body. It consists of two
lateral masses united by an anterior and posterior arch. The body
represented by the dens, a tooth like projection from the superior surface
of body of C2. Lamina is present in posterior arch. It is grooved on its
superior surface behind the lateral mass. The spine is replaced by the
posterior tubercle. The superior and inferior facets lie on the lateral
masses anterior to the first and second cervical nerves respectively.
The axis has a peg like projection in the upper part of body known
as dens (or) Odontoid process. It has a circular facet anteriorly,
articulating with atlas. There are two articular facets on either side.
Laminae are thick. The spine is large bifid and powerful. The transverse
processes are small and possess a tubercle on its tip.
Seventh Cervical Vertebrae
The spine is long and non-bifid. The transverse process does not
posses anterior tubercle. The foramen transversorium transmits only
Joints of Vertebral Column
The vertebrae from the 2nd cervical to lst sacral inclusive are
articulated to one another by series of cartilaginous joints between
vertebral bodies and a series of synovial joints between the vertebral
arches. The vertebral bodies are united by antero-posterior longitudinal
ligaments and by a central vertebral disc of fibro cartilage.
It is a synovial condyloid variety joint. Articular ends are
superiorly with convex occipital condyles, and inferiorly with superior
articular facets of the atlas. Ligaments, capsules, anterior and posterior
atlanto occipital membranes are the adjacent structures. Vertebral artery
supply to this joint. Nerve supply is by first cervical nerve. Movements
flexion, extension and lateral-flexion.
a) A pair of lateral atlanto axial joints and
b) Median atlanto-axial joints
a) Lateral Atlanto Axial Joint
Synovial Joint : Plane variety
Articular Ends : Inferior facets of atlas and superior facets of axis.
Ligaments : Anterior longitudinal ligament and
b) Median atlanto axial joint
Synovial Joint : Pivotvariety
Articular Ends : Between the dens of axis, anterior arch of atlas.
Ligaments : Transverse ligament
Movements : Rotatory movements around a vertical axis.
Ligaments Between the Axis and Occipital Bone:
1. Occipito – Axoid
2. Odontoid / Chech Ligaments
Movement – Limit the extend of rotation of craniam
The Unco Vertebral Joints (Luschka’s Joints)
These are not true synovial joints, which develop as a result of
degenerative changes in the edges of the disc in early adult life.
Luschka’s are important because
a) They are commonest site of osteophyte formation. These
osteophytes may compress the cervical nerves.
b) Vertebral artery lies lateral to the joints. Intruding on the canal
can cause distortion of the artery and leads to vertebro basilar
insufficiency in atherosclerotic vessels.
Blood supply of vertebral column:
Vertebrae and longitudinal muscles attached to them are supplied
by segmental arteries. The ascending cervical, intercostals, and lumbar
arteries give multiple small branches to the vertebral bodies. The extensor
muscles are supplied by occipital, deep cervical, and the transverse
cervical arteries. In thoracic and lumbar regions the muscle receives
posterior branches of the intercostals, lumbar, and lateral sacral arteries.
The internal venous plexus lies within the vertebral canal but
outside the spinal dura. It received tributaries from
i) The vertebrae through the basilo vertebral veins
ii) The meninges and the spinal cord
The internal vertebral venous plexus drained by the intervertebral
veins which passout through the intervertebral foramina. Here they are
joined by the tributaries from the external vertebral and sacral veins.
About the internal nervous plexus communicate with the occipital and
basilar veins through the foramen magnum.
Nerve supply of vertebral column
The anterior longititudinal ligament has rich innervation from the
vertebral plexus which derives sensory innervation from cervical,
glossopharyngeal and vagus nerves and autonomic supply from inferior
cervical and stellate ganglion. The sinus vertebral nerves and the
sympathetic fibers supply posterior longitudinal ligament and perisoteum.
The apophyseal joints and the interspinous ligaments are supplied by
dorsal rami. There is significant overlap of segmental innervation.