1) The cervical spine has 7 vertebrae connected by viscoelastic structures forming a flexible column for neuroprotection and support. 2) The C1 vertebra has anatomical landmarks including the sulcus arteriosus and the C2 vertebra has the odontoid process and transverse ligament. 3) The subaxial vertebrae have vertebral bodies, transverse processes, and pedicles connecting to the dorsal arch.

1. approach to cervical spine
dr himanshu soni

2. applied anatomy
• 7 vertebrae
• these segments are connected by an
extensive coplex of viscoelastic structures
to form a single flexible but constrained
column serving both neuroprotective and
structural function
• thorough understanding of the normal
relationshiops between these osseous,
discoligamentous and neural elements is
essential for safe and effective surgical
intervention

3. osseous elements
• C1
sulcus arteriosus
genu of vertebral artery - 1.5 to 2 cm from the midline on dorsal arch

4. • C2
– odoontoid process
– synovial joint
– apical ligament
– alar ligaments
– tr. AA ligament
– neck of the O. P.
• common site of fracture
– articular surfaces
– pars interartericularis
– sup and inf articulating surfaces - coronally offset
– forceful hyperextension, pars interartercularis breaks
• hangman's fracture
– foramen tranversarium
– C2 foramen is angulated 45 degrees laterally - VA is partially roofed by
artericular surface

9. • subaxial vertebra
– vertebral bodies
– uncovertebral joint - not a true joint
– transverse process
• foramen
• groove on superior surface - spinal
nerves
• tubercles - attachment of dorsal
musculature
– pedicles - connect the dorsal arch
angled medially between 38 to 48
degrees from saggital plane
– pedicles - range 6 to 6.5 mm
diameter
• thinnest along lateral wall, exposing
the risk of vertebral aftery damage
while screwig

11. • lateral mass column with articular surfaces
which are oriented obliquely on sagittal
plane
• affords axial load bearing
• oblique configuration restricts translation
• lateral mass serves as a common anchor
point for instrumentation
– rostral screw - protects nerve root
– lateral screw - protects the VA

18. discoligamentous structures
• disc space
– inferior endplate is concave causing taller disc
space at midbody
– discs constitute 20% of height
– height increases consecutively from C3-4 to
C7-T1 and space depth increases
– approx 16mm at C3 to 20mm at C7
– nucleus pulposus - 88% water at birth
– 64% at seventh decade
– nutrition by diffusion
– immune - isolated avascular space
– Sharpey fibers

20. • ALL
• PLL
• ligamentum flavum
• intertransverseligaments
– restrict lateral bending
• inter spinous ligaments
• nuchal ligament
– from occ protruberance to sp pr of C7
– thick elastic fibrous - resists hyperflexion
– forms posterior tension band

23. neural structures - cervical cord
• cylindrical, symmetrical
• ventral median fissure - anterior
spinal artery, true space
• posterior median sulcus -
seperated hemicords
• anterolateral sulcus -
emergence of ventral / motor
roots
• dorsolateral sulcus - dorsal /
sensory roots
• three columns : anterior, lateral
and posterior
• posterior column - medial
gracilis and lateral cuneatus
fasciculus
• cord segments approx same
level as the column segment

24. neural structures - spinal nerves
• anterolateral sulcus - 1-3 mm lateral to midline
– multiple rootlets
– allows intradural anastomosis causing atypical
distribution of radiculopathies
• dorsal rootlets
– proprioceptive large fibres run medially and
ventrally
– small pain fibres located laterally and dorsally
• both traverse the intervertebral foramen above
the same pedicle ( C5 through C4-5 foramen
above C5 pedicle )
• C1 has no DRG and hence no dermatome

25. intervertebral foramen
• dorsal roots more rostrally hence comprression affects
disproportionately
• exiting root - oblique with a ventrolateral trajectory
• at origin
– bounded ventromedially by the UV joint
– laterally, the nerve root and DRG abut the VA
– UV hypertrophy and lateral discs cause radiculopathy
– UV hypertrophy also distorts the VA causing secondary
compression on the exiting root or DRG
• dorsolateral wall
– superior and inf articular processes, hence facet hypertrophy
triggers radiculopathy
– basis of Spurling's maneuver
• the roots lie more caudally, abutting the subjacent pedicle

28. VASCULAR ANATOMY
• SPINAL CORD PERFUSION
• three principal arteries
– the anterior spinal artery
– paired posterio spinal arteries
• none of these vessels represent single
vessels that traverse teh entire length of
spinal cord
• they are anastomotic, interrupted,tudinal
vessels, drawing supply from numerous
segments.

29. • spinal cord perfusion is achieved by
– two indenpendent vasular systems :
• the centripetal ssytem
– runs along the perimeter of the spinal cord in
perimedullary plexus
– gives rise to arteries that penetrate radially into the cord
parenchyma
• the centrifugal system
– originates deep within the anterior median fissure from
branches of the ASA
– the centripetal system perfuses the white
matter
– centrifugal system perfuses the gray matter

30. • the ASA
– descending branches of bilateral intracrahial
vertebral arteries
– enters the midline ventral median fissure
– supplies ventral two thirds of the cord
– infarct causes dysfunction of
• the anterior columns
• spinothalamic tracts
• corticospinal tracts

31. • the PSAs
– intracranial vertebral arterires or teh PICAs
– run in the dorsolateral sulci
– form a peripheral anastomotic plexus
– perfuses the dorsal one third.

32. • cervical segmental vessels
– paired, arise from the verterberaltery and
branches of the cubclavian arteries
– perfuse the spinal roots and DRG before
entering the intervertebral foramen
– 3 branches
• the dural - perfuses spinal dura and nerve
root sleeve
• radicular - dura and ventral and dorsal
nerve roots
• medullary - anastomoses with the ASA
within one or two levels of origin

33. • VERTEBRAL ARTERY
– paired, arises from the subclavian artery, from the
innominate artery or from the aorta
– course is divided into four segments
– V1: origin to foramen transvarserium
• 87.5 % - at C6 level
• 5.4% - at C7 level
• 6.6 % - at C5 level
• 0.4% - at C4 level
– V2: traverses the FT, ends after C2 FT
• most vulnerable segment
• may have a tortuous course
• FT is closer to UV joint, warranting cautious drilling

34. – V3: until the VA penetrates the dura
– V4: intradural portion, ends at the VB junction

35. • muscular and osseous branches - each level
• anterior and posterior central arteries
– epidural plexus
– perfuses the vertebral bodies
• anterior and posterior ascending arteries
– at C2 level, anastomose to perfuse the
antlantoaxial complex
• collateral recruitment
– thyrocervical and costocervical in the lower spine
– ascending pharyngeal and occipital in the uppper
cervical spine

36. • odontoid process
– base - ascending branches of the VA
– tip - apical artery of the OP, branch from the
hypoglossal artery

37. • Venous anatomy
– The intrinsic spinal cord is drained
centrifugally by radially oriented veins that
empty into a circumferential venous plexus
called the vasa corona.
– The dorsal half of the spinal cord venous
drainage empties into this plexus, eventually
converging on the median dorsal longitudinal
vein,
– whereas the ventral half of the spinal cord
drainage empties into a comparable plexus,
eventually draining into the median ventral