The human spinal column consists of 33 vertebrae organized into five regions. The vertebrae are interconnected by discs and supported by ligaments. Each region has characteristics suited to its location and functions. The cervical region has the greatest flexibility to allow rotation of the head. Facet joints and curvatures of the spine constrain and guide its range of motion. The vertebrae, discs, ligaments, muscles and curvatures work together to support the structure and movement of the spine.

1. SPINE ANATOMY
HIMANSHU SONI

2. overview
• human spinal column consists
of 33 vertebra
• five regions
• 7 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 4 coccygeal bones
• in utero development plays a
large part in the formation of
adult spine contributing to
primary curvatures
• during the early childhood the
secondary curves develop

3. • the cervical and lumbar lordosis - because of the
gravitational forces created by the weight of the head
in uprigh posture
• they allow for horizontal gaze while standing
• the development and maintainance is a dynamic state
• variations in IV discs and bodies by
• congenital anomalies
• age dependent changes
• osteophyte formation
• traumatic injuries
• neurologic disorders
• paraspinal muscle imbalances

5. • common variations
• sacralisation / lumbarisation of L5/S1
• Klippel Feil anomaly in the c spine
• anamolous nerve root anatomy

6. flexibility
• allows compensation of deformities
• varies from region to region
• cervical spine - greatest flexibility
• thoracic - least
• unique articulations in the c spine afford
immense flexibility
• influenced by
• cartilaginous discs
• apophyseal joints dorsal to the vertebral arches

7. centre of gravity
• begins at - odontoid of the axis vertebra
• the CG of the spinal column and the body donot
pass throught the same point
• the spinal column CG
• passes through the centre of sacral promontory
• the body CG
• passes ventral to the sacaral promontory
• if the CG of the body is too ventral, the work
required to maintain the erect posture is
significantly increased - f/b pain and lumbar
muscle fatigue

9. ligaments
• composed of elastin and
collagen
• may span several segments
• ANTERIOR LONGITUDINAL
LIGAMENT (ALL)
• spans the entire length of
the column
• begins as anterior antlanto-
occipital membrane upto
the sacrum
• spans 25-33% of ventral
surface of bodies and discs
• supports annulus fibrosus
• prevents hyperextention
• arranged in three layers

11. • the outermost layer - spans 4-5
levels
• middle layer - spans 3 levels
• innermost layer - binding
adjacent discs
• POSTERIOR LONGITUDINAL
LIGAMENT
• begins as tectorial membrane at
C2 to the sacrum
• runs withing the canal and
flares at the level of the disc
• interwoven with the annulus
and narrows at the bodies
• layers are similar to the ALL
• prevents hyperflexion

12. • LIGAMENTA FLAVA
• connect the spinal laminae in discontinuous fashion
• interwoven with the facet joint capsule
• extends from ventral part of cranial lamina to the dorsal
part of caudal lamina
• laterally in contact with the ventral capsule of facet
• contains 80% elastin, which is yellow and hence “flava”
• elasticity allows it to stretch during extension
• with age, is replaced by collagen, which is less elastic and
leads to buckling into the canal

14. vertebrae
• The compressive forces are
significant in a stacked
column, and the cortical
lamellae are arranged
vertically to aid in resisting
these forces.
• The cancellous bone found
in the inner trabeculae
allows for a compromise
between strong mechanical
support and limiting
vertebral weight.

15. vertebrae
• All of the structures coincident with the vertebral bodies act to bear
weight in compression.
• The anterior column functions to transfer body weight to the pelvis
while standing in an erect posture.
• Dorsal elements of the spinal column serve to protect the spinal cord
and act as a tension band and a lever, transferring muscular
contractions of the paraspinal musculature through the anterior and
middle columns of the spine

16. dorsal elements
• The dorsal bony elements include
the pedicles, which arise from the
superior aspect of the vertebral
body and form the lateral walls of
the spinal canal.
• The laminae extend from the pars
interarticularis and fuse to form the
dorsal wall of the spinal column.
• The junction of the laminae, where
the spinous processes arise, support
functional stability of the spine with
their ligamentous and muscular
attachments.

17. dorsal elements
• The relationship between the
transverse processes and the
dorsal elements is unique to
the specific spinal region
where they are found.
• Cervical transverse processes
arise from the junction of the
vertebral body and pedicle.
• The shape of cervical spinous
processes are bifid, resulting
in the great flexibility of the
cervical region. .

18. dorsal elements
• Thoracic and lumbar
transverse processes have a
different anatomic
relationship with the dorsal
elements, arising from the
junction of the pars
interarticularis and pedicle.
• Stability and motion to the
spine are also provided by
transverse processes with
their unique ligamentous
and muscular attachments.

19. facet joints
• Flexion, extension, and rotation of the
spine are supported, facilitated, and
restricted by the facet joints.
• A facet joint consists of a superior
articular process with an articulating
surface projecting dorsally, which is met
by the adjacent vertebra’s inferior
articular process that projects its
articulating surface ventrally.
• The synovial joint formed by the two
processes consists of a thin layer of
hyaline cartilage between matching
articulating surfaces, lined with
synovium and surrounded by a joint
capsule.
• Although limited in size, the facet joints
provide constraints to extremes of spinal
motion.

20. TYPICAL CERVICAL
VERTEBRA
• A typical cervical vertebra has a
small, relatively broad vertebral
body.
• The pedicles project
posterolaterally and the longer
laminae posteromedially,
enclosing a large, roughly
triangular vertebral foramen; the
vertebral canal here
accommodates the cervical
enlargement of the cord.

21. • The pedicles attach midway between
the discal surfaces of the vertebral
body, so the superior and inferior
vertebral notches are of similar
depth.
• The laminae are thin and slightly
curved, with a thin superior and
slightly thicker inferior border.
• The spinous process (‘spine’) is short
and bifid, with two tubercles that are
often unequal in size.
• The junction between lamina and
pedicle bulges laterally between the
superior and inferior articular
processes to form an articular pillar
(‘lateral mass’) on each side.

22. • The transverse process is
morphologically composite
around the foramen
transversarium.
• Its dorsal and ventral bars
terminate laterally as
corresponding tubercles.
• The tubercles are connected,
lateral to the foramen, by the
costal (or intertubercular)
lamella; these three elements
represent morphologically the
capitellum, tubercle and neck
of a cervical costal element

23. • The attachment of the dorsal bar to the
pediculolaminar junction represents the
morphological transverse process, and the
attachment of the ventral bar to the ventral
body represents the capitellar process.
• In all but the seventh cervical vertebra, the
foramen transversarium normally transmits the
vertebral artery and vein and a branch from the
cervicothoracic ganglion (vertebral nerve).

25. • The vertebral body has a convex
anterior surface.
• The discal margin gives
attachment to the anterior
longitudinal ligament.
• The posterior surface is flat or
minimally concave, and its discal
margins give attachment to the
posterior longitudinal ligament.
• The central area displays several
vascular foramina, of which two
are commonly relatively larger.
• These are the basivertebral
foramina, which transmit
basivertebral veins to the anterior
internal vertebral plexus.

26. • The superior discal surface is
saddle-shaped, formed by flange-
like lips, uncinate processes,
which arise from most of the
lateral circumference of the upper
margin of the vertebral body.
• Uncinate processes are
rudimentary at birth and are
usually found on the third to
seventh cervical vertebra in the
adult.
• The uncinate processes on the
vertebra below articulate with the
corresponding bevelled surfaces
on the inferior aspect of the
vertebra above.

27. • The inferior discal surface is also concave; the
concavity is produced mainly by a broad
projection from the anterior margin, which
partly overlaps the anterior surface of the
intervertebral disc.
• The discal surfaces of cervical vertebrae are so
shaped in order to restrict both lateral and
anteroposterior gliding movements during
articulation.

28. • The paired ligamenta flava extend
from the superior border of each
lamina below to the roughened
inferior half of the anterior
surfaces of the lamina above.
• The superior part of the anterior
surface of each lamina is smooth,
like the immediately adjacent
surfaces of the pedicles, which are
usually in direct contact with the
dura mater and cervical root
sheaths to which they may become
loosely attached.
• The spinous process of the sixth
cervical vertebra is larger and is
often not bifid.

29. • The superior articular facets, flat and ovoid, are
directed superoposteriorly, whereas the
corresponding inferior facets are directed
mainly anteriorly, and lie nearer the coronal
plane than the superior facets.
• In children, facet joint angle decreases until 10
years of age and remains unchanged thereafter
(Kasai et al 1996).

30. • The dorsal rami of the cervical
spinal nerves curve posteriorly,
close to the anterolateral aspects of
the lateral masses, and may actually
lie in shallow grooves, especially on
the third and fourth pairs.
• The dorsal root ganglion of each
cervical spinal nerve lies between
the superior and inferior vertebral
notches of adjacent vertebrae.
• The large anterior ramus passes
posterior to the vertebral artery,
which lies on the concave upper
surface of the costal lamella; the
concavity of the lamellae increases
from the fourth to the sixth
vertebra.

31. muscle attachments
• The ligamentum nuchae and numerous deep
extensors, including semispinalis thoracis and
cervicis, multifidus, spinales and interspinales, are all
attached to the spinous processes.
• Tendinous slips of scalenus anterior, longus capitis
and longus colli are attached to the fourth to sixth
anterior tubercles.
• Splenius, longissimus and iliocostalis cervicis, levator
scapulae and scalenus posterior and medius are all
attached to the posterior tubercles.
• Shallow anterolateral depressions on the anterior
surface of the body lodge the vertical parts of the
longus colli

35. ATLAS (C1)
• The first cervical vertebra is unique
in its articulation with the occipital
condyle of the cranium.
• This articulation is the basis for
significant flexion and extension of
the head.
• Another unique aspect of the atlas
is that although it lacks a true
ventral body it still supports the
cranium by the superior facet
surfaces of the lateral masses.
• The caudal facet surfaces of the
lateral mass articulate with the
superior facets of the axis.
• The transverse process of the atlas
houses the vertebral artery within
the transverse foramina.

37. • Superior and inferior oblique muscles attach to
the transverse process.
• The atlas is hydrostatically held between the
cranium and axis.
• The anterior and posterior occipital membranes
attach to the atlas and also contribute to stability.
• They are continuations of the anterior
longitudinal ligament and ligamentum flavum,
respectively.

38. AXIS (C2)
• The articulation between the atlas and axis,
known as the atlantoaxial joint, contributes
to the majority of cervical rotation and
stability to the upper cervical region.
• Unlike the atlas, the axis does have a true
vertebral body and a unique structure
known as the odontoid process projecting
cranially from its dorsal aspect.
• The alar, cruciform, and transverse
ligaments are anchored to the odontoid
process.
• Further stability of the cervical region is
contributed to by the muscular
attachments at the spinous process of the
axis, which include the rectus major and
inferior oblique muscles.
• Like the atlas, a transverse foramen
encases the vertebral artery.

39. ligaments of CV junction
• Much of the stability of the craniocervical
region is provided by the ligaments within the
spinal canal, which are ventral to the spinal
cord.
• These are arranged in three layers. The tectorial
membrane is the most dorsal of these ligaments
and is a continuation of the PLL, attaching
dorsally to the cruciate ligament at the
basiocciput.
• The cruciate ligament is the middle layer and
functions to constrain ventral translation
between C1 and C2.

42. • It is a complex ligament with both horizontal
and vertical bands.
• The odontoid ligament, or apical ligament, is
the most ventral of the inner ligaments and
extends from the lateral aspect of the odontoid
to the medial aspect of the occipital condyles.
• Outside of the spinal canal are fibroelastic
bands extending from the foramen magnum to
C1.

43. • From the ventral portion of the foramen
magnum extends the anterior atlantooccipital
membrane.
• From the dorsal foramen magnum arises the
posterior atlanto-occipital membrane.
• Because these are thin bands, their contribution
to the strength of the cervical spine is limited.

44. range of motion
• The range of motion measure at the cervical
spine can vary due to age, gender, and method
of measurement.
• Visual estimation and radiography are the
primary methods used to measure cervical range
of motion.
• Studies of these measurement techniques on
active cervical range of motion havefound that,
on average, the cervical spine has a total of 151
degrees of rotation, a total of 86 degrees of
lateral bending, and a total of 126 degrees of
flexion-extension.

46. • When considering motion in only one direction,
leftward and rightward rotation and lateral
bending are, on average, half the total values,
whereas the cervical spine has, on average, a
greater range of extension than flexion.

47. • thank you