spine anatomy

1. Clinical Spinal Anatomy
By
Dr.Usman Haqqani
NSBW

2. ANATOMY OF VERTEBRAL COLUMN
Vertebral column -33 vertebrae divided into five sections
 seven cervical
 twelve thoracic
 five lumbar
 five sacral
 four coccygeal
vertebral body increases in size from cranial to
caudal.

3. Curvature Normal Curvature
Cervical Lordosis 20 to 40 degrees
Thoracic Kyphosis 20 to 40 degrees
Lumbar Lordosis 40 to 60 degrees
Sacral Kyphosis
Sacrum fused in a
kyphotic curve
Type of Spinal
Curves
Curve Description
Kyphosis or
Kyphotic Curve
Concave anteriorly
and convex
posteriorly
Lordosis or Lordotic
Curve
Convex anteriorly
and concave
posteriorly

4. TYPICALVERTEBRA
• Vertebral body
• Verebral arch
• Processes
– Pedicle
– Lamina
– Spine
– Transverse processes
– Superior and inferior
articular processes

5. • articular processes : The orientation of
the facets joints formed by the articular
process determines the degree and plane of
motion at that level varies throughout the spine
to meet physiologic function.
• spinous and transverse processes : levers
for the numerous muscles attached to
them.

6. • total of six joint
– 2 Superior and 2inferior
facet joints
– 2interbody joints
containing intervertebral
discs
(found throughout the
vertebral column except between
the first and second cervical
vertebrae)

7. • intervertebral foramen is formed by
:
– inferior vertebral notch on the pedicle of
the vertebra above
– superior vertebral notch on the pedicle
of the vertebra below.
– The foramina allow structures, such as
spinal nerves and blood vessels, to
pass in and out of the vertebral canal.

8. Cervical spine
The cervical spine contains 7
vertebral bodies
C1 (atlas)
C2 (axis)
C2 to C6
have bifid spinous
process

9. • C1 to C7
– have a transverse foramen
– vertebral artery travels
through transverse
foramen of C1 to C6
C7
despite having a transverse
foramen, the vertebral artery
does NOT travel through it in
the majority of individuals
there is no C8 vertebral body
although there is a C8 nerve
root
• The first , second and seventh
cervical vertebrae are atypical

10. Vertebral artery travels along the superio lateral surface of c1 arch aproximately
1.5cm from the midline

11. Cervical spine
• Alignment
– Normal sagittal
lordosis 20 to 40
degrees
– (measured from C2
to C7)
• Spinal canal
– normal diameter is
17mm
– <13mm indicates
possible cord
compression

12. C1 Atlas
• Has no vertebral body
and no spinous process
• Articulations
– occiput-C1
• two superior concave
facets that articulate with
the occipital condyles
• makes up 50% of neck
flexion and extension)
allows the head to nod up
and down on the vertebral
column.

13. • The transverse
processes of the atlas
are large and protrude
further laterally than
those of the other
cervical vertebrae

14. C2 Axis
• Has odontoid process (dens) and body
• C2 Blood Supply vascular watershed exists
between the apex and the base of the
odontoid
– apex is supplied by branches of internal carorid
artery
– base is supplied from branches of vertebral artery
– the limited blood supply in this watershed area is
thought to affect healing of type II odontoid
fractures.

15. CI-C2 (atlantoaxial) articulation
• CI-C2 (atlantoaxial) allows
– 50 (of 100) degrees of cervical rotation
– 10 (of 110) degrees of flexion/extension
– 0 (of 68) degrees of lateral bend

16. Occipital-C1-C2 Ligamentous
Complex
• odontoid process and its
supporting ligaments
– transverse ligament
• limits anterior translation of the
atlas
– apical ligaments
• limit rotation of the upper
cervical spine
– alar ligaments
• limit rotation of the upper
cervical spine

17. Subaxial Cervical Spine (C3 to C7)
• C1 to C7
– have a transverse foramen
– vertebral artery travels through transverse
foramen of C1 to C6
• C2 to C6
– have bifid spinous process
• C6
– contains palpable carotid tubercle which is a
valuble landmark for anterior approach to
cervical spine
• C7
– nonbifid spinous process
– despite having a transverse foramen, the
vertebral artery does NOT travel through it in
the majority of patients
– there is no C8 vertebral body although there
is a C8 nerve root
• The superior articular facets of the
subaxial cervical spine (C3-C7) are
oriented in a posteromedial direction at
C3 and posterolateral direction at C7,
with a variable transition between these
levels

18. Landmarks and surface
anatomy

19. Thoracic spine
• Alignment
– normal thoracic kyphosis averages
35° degrees
– normal range is 20° to 50°

20. • Vertebral prominens
– the long prominent spinous process found at T1
• Costal facets
– articulation between ribs and vertebral segments
– present on all vertebral bodies and transverse processes from T1 to T9
– articulation with ribs leads to increased rigidity of thoracic spine (most rigid in axial skeleton)
• Vertebral body size
– increases progressively from T1 to T12
• Spinal canal dimensions
– varies from T1 to T12

21. Thoracic Pedicle Anatomy
• Pedicle diameter
– T4 has the narrowest pedicle diameter (on average)
– T12 usually has larger pedicle diameter than L1

22. • Pedicle length
– pedicle length decreases from T1 to T4 and
then increases again as you move distal in
the thoracic spine
• T1: 20mm
• T4: 14mm (shortest pedicle)
• T10: 20 mm

23. • Pedicle angle
– transverse pedicle
angle
• varies from 10deg
(mid thoracic
spine) to 30deg
(L5)
– sagittal pedicle
angle
• About 15 deg
cephalad for
majority of thoracic
spine
• neutral (0deg) for
lumbar spine
except L5 (caudal)

24. Erector Spinae Muscles
• Characteristics
– functions to extend the trunk
– located dorsal to vertebral column
– innervated by dorsal rami of
spinal nerves
• Erector spinae muscles include
– spinalis
• most medial
• origin and insertion: spinous
process to spinous process
– longissimus
• intermediate
• origin and insertion: transverse
process to transverse process
– iliocostalis
• most lateral
• origin: ilium and ribs
• insertion: ribs and transverse
process

25. Lumbar Spine Anatomy
• Alignment
– Sagittal planelumbar lordosis
– average of 60 degrees
– apex of lordosis at L3
– disc spaces responsible for most of lordosis

26. • Lumbar spine has the
largest vertebrae bodies in
the axial spine
• Components of vertebral
bodies
– anterior vertebral body
– posterior arch
• formed by
– pedicles
– lamina
– spinous process
– transverse process
– mammillary processes
• project posteriorly from
superior articular facet
– pars interarticularis
• site of spondylolysis

27. • Articulations
– intervertebral disc
• act as an articulation above and below
– facet joint (zygapophyseal joint)
• formed by superior and inferior articular processes
that project from junction of pedicle and lamina
• facet orientation
– facets become more coronal as you move inferior

28. Lumbar Pedicle Anatomy
• Landmarks
– midpoint of the transverse process used to identify
midpoint of pedicle in superior-inferior dimension
– lateral border of pars used to identify midpoint in
medial-lateral dimension
• Pedicle angulation
– pedicles angulate more medial as you move distal
• Pedicle diameter
– L1 has smallest diameter in lumbar spine (T4 has
smallest diameter overall)
– S1 has average diameter of ~19mm

29. Lumbar Blood Supply
• Lumbar vertebral
bodies supplied
by segmental
arteries
– dorsal branches
supply blood to
the dura &
posterior
elements

30. Lumbar Neurologic Structures
– anatomy
• nerve root exits foramen under same numbered pedicle
– central herniations affect traversing nerve root
– far lateral herniations affect exiting nerve root
• horizontal (cervical) vs. vertical (lumbar) anatomy of nerve
root
– because of vertical anatomy of lumbar nerve root a paracentral and
foraminal disc will affect different nerve roots
– because of horizontal anatomy of cervical nerve root a central and
foraminal disc will affect the same nerve root
• Cauda equina
– begins at ~L1

31. Sacrum and coccyx
• The sacrum is a single bone : five fused sacral vertebrae.
• Curved and triangular in shape with the apex pointed inferiorly
• 4 sacral foramina
• Sacral canal contains:
• roots of sacral and coccygeal spinal nerves
• Filum terminale
• Fibrofatty material

32. LIGAMENTS
• The anterior longitudinal ligament :
– anterior surfaces of the vertebral
bodies
– base of the skull to the anterior
surface of the sacrum.
– attached to the vertebral bodies and
intervertebral discs along its length.
• The posterior longitudinal ligament:
– posterior surfaces of the vertebral
bodies
– lines the anterior surface of the
vertebral canal.
– attached along its length to the
vertebral bodies and intervertebral
discs.

33. • Tectorial membrane :
The upper part of the
posterior longitudinal
ligament that connects
C2 to the intracranial
aspect of the base of
the skull

34. LIGAMENTA FLAVA
• between the laminae of adjacent vertebrae
• thin, broad ,yellow in color
• runs between the posterior surface of the lamina on the vertebra below to
the anterior surface of the lamina of the vertebra above
• resist separation of the laminae in flexion
• assist in extension back to the anatomical position

35. SUPRASPINOUS LIGAMENT AND
LIGAMENTUM NUCHAE
• The supraspinous ligament:
along the tips of the
vertebral spinous
processes from vertebra
C7 to the sacrum
• From vertebra 7 to the
skull, the ligament is called
the ligamentum nuchae.
– supports the head and resists
flexion and facilitates
returning the head to
anatomical position

36. INTERSPINOUS LIGAMENTS
• pass between adjacent
vertebral spinous processes
• blend with the supraspinous
ligament posteriorly and the
ligamenta flava anteriorly

37. Intervertebral Disc
• The discs are the largest
avascular structures in the
body
• Central
– nucleus pulposus - semifluid
mass of mucoid material .
gelatinous, and absorbs
compression forces between
vertebrae.
• Peripheral
– ring of anulus fibrosus
12 concentric lamellae, with
alternating orientation of
collagen fibers in successive
lamellae to withstand
multidirectional strain.

38. VARIATIONS IN THE VERTEBRAE
• C7 may possess a cervical rib
• Thoracic vertebrae may be increased in number by
addition of the L1 vertebra which may have a rib.
• L5 may be incorporated into the sacrum
• S1 may remain partially or completely separate from
sacrum and resemble a 6th Lumbar vertebra.
• Coccyx which consists of four fused vertebra may have 3
or 5 vertebrae.

39. POSTERIOR SPACES BETWEEN VERTEBRAL
ARCHES
• In most regions the laminae and spinous processes of
adjacent vertebrae overlap to form a complete bony dorsal
wall for the vertebral canal.
• in the lumbar region, large gaps exist between the
posterior components of adjacent vertebral arches.
• become increasingly wide from vertebra LI to vertebra LV.
• The spaces can be widened further by flexion of the
vertebral column.
• allow relatively easy access to the vertebral canal for
clinical procedures.

40. POSTERIOR SPACES BETWEEN VERTEBRAL ARCHES

41. Thank you 