Anatomy of spine

1. ANATOMY OF
SPINE
Dr Pankaj N Surange
MBBS, MD, FIPP
Interventional Pain and Spine specialist

2. A-P X-ray of a
scoliotic spine in
the coronal plane.
The CORONAL PLANE, also
called the FRONTAL PLANE, is a
vertical cut that divides the body
into front and back sections.
Physicians look at the coronal plane
when they view an A-P (anterior-
posterior) x-ray of the spine to
evaluate scoliosis.
Anatomical Planes

3. Lateral X-ray of a
kyphotic spine in
the sagittal
plane.
The SAGITTAL or MEDIAN
PLANE is a vertical cut that
divides the body into left and right
sections. The sagittal view is seen
by surgeons on a lateral x-ray of
the spine.
Anatomical Planes

4. CT Scan of a
thoracic vertebra
in the axial plane.
The AXIAL or TRANSVERSE
PLANE is a horizontal cut that
divides the body into upper and
lower sections. To best view the
axial plane of the spine, surgeons
will often obtain a CT scan with
axial cuts.
Anatomical Planes

5. •Protection of
–spinal cord and nerve roots
–internal organs
Functions of the Spine

6. •Flexibility of motion in six degrees of freedom
Left and Right
Side Bending
Flexion and Extension
Left and Right Rotation
Functions of the Spine

7. •Structural support and
balance for upright posture
The spine is the axle bearing the load
of the head, shoulders and thorax. The
upper body weight is then distributed
to the lower extremities through the
sacrum and pelvis.
This reduces the amount of work
required by the spinal muscles and can
eliminate muscle fatigue and back pain.
Functions of the Spine

8. To achieve these functions, the spine
must have:
•Resistance to axial loading forces,
accomplished by:
–Kyphotic and lordotic sagittal plane
curves
–Increased mass of each vertebra
from C1 to the sacrum
•Elasticity accomplished by:
–Alternating lordotic and kyphotic
curves
–Multiple MOTION SEGMENTS
Functions of the Spine

9. •The FUNCTIONAL UNIT of the spine
•Composed of:
–Connecting ligaments
–Two adjacent
vertebrae–The intervertebral disc
–Two facet joints and
capsules
The Motion Segment

10. •Primary Curves
Sagittal Plane Curves
•Secondary Curves

11. Cervical Lordosis 20°- 40°
Sacral Kyphosis
Lumbar Lordosis 30°- 50°
Thoracic Kyphosis 20°- 40°
Sagittal Plane Curves

12. •Cervical
–Upper cervical: C1-C2
–Lower cervical: C3-C7
•Sacrococcygeal: 9 fused
vertebrae in the sacrum and
coccyx.
•Thoracic: T1-T12
•Lumbar: L1- L5
Regions of the Spine

13. •Line of gravity
Auricle of the ear
Odontoid
Body of C7
Anterior to thoracic
spine
Posterior to L3
Mid femoral heads
Regions of the Spine

14. Basic Vertebral StructuresBasic Vertebral Structures
Cervical Thoracic Lumbar

15. There are two types of bone tissue:
•Cortical bone: dense, outer shell of the
vertebra
Detail of Cortical
Bone
Haversian System
Detail of Cancellous
Bone
•Cancellous bone: inner, spongy bone
Types of Bone Tissue

16. Vertebral
Body
Pedicle
Lamina
Superior
Articular
Process
Spinous
Process
Transverse
Process
Vertebral
Foramen
Vertebral Structures

17. Superior
Articular
Process
Inferior
Articular
Process
Zygapophyseal
Joint
(Facet Joint)
Pars
Vertebral Structures

18. Vertebral Structures
•Pedicle notches
Slight
Notch
Deep
Notch
Intervertebral
Foramen
•INTERVERTEBRAL FORAMEN
through which the spinal nerve
roots leave the spinal cord

19. •Anterior Arch
Comprised of:
–Vertebral body
–Anterior 1/3 of the pedicles
•Posterior Arch
Comprised of:
–Posterior 2/3 of the pedicles
–Lamina
–Processes
Vertebral Arches

20. The Atlas (C1)
Transverse
Process
Transverse
Foramen
Anterior
Tubercle
Articular Facet
for Dens
Lateral
Mass
Lamina
Posterior
Tubercle
Superior
Articular
Facet
Superior View

21. The Axis (C2)
Odontoid
Process
(Dens)
Body
Transverse
Process
Inferior
Articular
Facet
Superior
Articular
Facet
Anterior View Posterior View
Lateral
Mass
Spinous
Process

22. Lower Cervical Vertebrae
•C3 to C7
–May be referred to as
the subaxial region
–Disc at every level
–Vertebral structures
are similar

23. Lower Cervical Vertebrae
C3 - C7
Transverse
ProcessBody
Sulcus for
Spinal Nerve
Lateral
Mass
Lamina
Pedicle
Superior
Articular Facet
Vertebral
Foramen
Bifid Spinous Process
Transverse
Foramen
Axial View

24. Sulcus for
Spinal Nerve
Uncinate
Process
Uncovertebral Joint
(Joint of Luschka)
Lower Cervical Vertebrae
C3 - C7
Anterior View
The vertebral bodies of the subaxial cervical spine have upward projections on
the lateral margins called UNCINATE PROCESSES .
These processes articulate with the level above to form the UNCOVERTEBRAL
JOINT. These are also called JOINTS OF LUSCHKA.

25. Vertebra Prominens (C7)
Spinous
Process
Axial View
C7 is referred to as the VERTEBRA
PROMINENS because it has a longer
and larger spinous process than the
other cervical vertebrae.
This spinous process is not usually bifid.

26. Thoracic Vertebrae
•Body - progressive increase in mass
from T1 to T12
•Pedicles - small diameter
•Laminae - vertical, with “roof tile”
arrangement
•Spinous processes - long,
overlapping, projected downward
•Intervertebral foramen - larger, less
incidence of nerve compression

27. Thoracic Vertebrae, T1-T12
•Body - heart shaped when viewed
superiorly.
•Vertebral foramen - round
•Pedicles - small in diameter
•Spinous processes - long and
projected downwards

28. •Articular processes
Superior Articular
Process
Inferior Articular
Process
Thoracic Vertebrae, T1-T12

29. •Body - L1 to L5 progressive increase
in mass
•Pedicles - longer and wider than
thoracic; oval shaped
•Spinous processes - horizontal,
square shaped
•Transverse processes - smaller than
in thoracic region
•Intervertebral foramen - large, but
with increased incidence of nerve
root compression
Lumbar Vertebrae, L1-L5

30. The Sacrum
Sacral Horns
Sacral Ala
Pedicles
Dorsal
Foramina
Sacral
Hiatus
Coccyx
Posterior View
Inverted triangle shape

31. Coccyx
Lateral View
Sacral
Promontory
Sacral Tilt
30°-60°
Sacral Canal
1
2
3
4
5
Sacral Hiatus
The Sacrum

32. •Intervertebral disc
•End plate
•Apophyseal ring
–Cartilaginous layer
–Bony layer
Intervertebral Disc

33. •Fibrocartilaginous joint of the
motion segment
•Make up ¼ the length of the
spinal column
•Present at levels C2-C3 to L5-
S1
•Allows compressive, tensile,
and rotational motion
•Largest avascular structures
in the body
Intervertebral Disc

34. Intervertebral Disc
•Annulus Fibrosus
–Outer portion of the disc
Lamellae
–Great tensile strength
–Made up of lamellae
Annulus
Fibrosus
•Layers of collagen fibers
•Arranged obliquely 30°
•Reversed contiguous
layers

35. Intervertebral Disc
•Nucleus Pulposus
Nucleus
Pulposus
–Inner structure
–Gelatinous
–High water content
–Resists axial forces

36. Blood Supply
•Intervertebral discs have no
significant vascular structures.
•They receive their blood supply by
diffusion through the vertebral body
endplates.
• A network of vessels located
centrally in the endplate allows
nutrients to diffuse into the nucleus
pulposus and annulus fibrosus.
Intervertebral Disc

37. Occipitocervical Joint
Occipital
Condyles
Foramen
Magnum
articulate with
C1 superior
facets

38. Atlantoaxial Joint
C1
C2
Dens
Zygapophyseal
joints
JOINT between the atlas (C1) and the
axis (C2); has a range of motion in the
transverse plane for rotation.
The DENS of C2 acts as a
pivot point for the rotation of
C1.
The articulating surfaces of the two
vertebrae form ZYGAPOPHYSEAL
(FACET) JOINTS that allow flexion-
extension, side bending, and
rotational movements.

39. Also called ZYGAPOPHYSEAL JOINTS .
The facet joints are formed by the
articular processes of adjacent vertebrae.
The inferior articular process of a vertebra
articulates with the superior articular
process of the vertebra below.
These are synovial gliding joints
Facet joints are oriented in different
planes depending on their anatomic
location.
The Facet Joints

40. Uncovertebral Joints
Uncovertebral
Joint
The bony elevations on the
superior lateral margins of the cervical
vertebrae are called UNCINATE
PROCESSES.
The uncovertebral joints are not true
joints
These joints articulate with the
inferior, lateral aspect of the vertebra
above to form the UNCOVERTEBRAL
JOINTS, also known as the JOINTS
OF LUSCHKA. These are fibrous joints
Uncinate
Process

41. The T2-T9 thoracic vertebra
have facets superiorly and inferiorly
at the posterior aspect of the
vertebral body that form the
COSTOVERTEBRAL joints.
Costovertebral Joints
Costovertebral
joints
Rib
Costotransverse
joints
Axial View
In the thoracic spine, the RIBS
articulate with the vertebrae at both the body
and the transverse processes.
At all thoracic levels there is a
facet where the rib articulates with
the transverse process. These are
called the COSTOTRANSVERSE
joints.
The T1 and T10-T12 vertebral
bodies have only one costal facet.
Rib

42. Lateral View
Costovertebral
joints
Costotransverse
joint
Rib
Costovertebral Joints

43. Sacroiliac Joint
Sacroiliac
Ligaments
Sacrum
Ilium
The superior lateral surface on
either side of the sacrum articulates
with the inner aspects of the pelvis.
This area forms the capsular, synovial
SACROILIAC JOINT.
In some cases the
sacroiliac joint is a
hidden source of back
pain.

44. Upper Cervical Ligaments
Occipitoatlantal
Ligament Complex
Anterior
occipitoatlantal
ligament
Posterior
occipitoatlantal
ligament
Lateral
occipitoatlantal
ligament
Anterior View

45. Upper Cervical Ligaments
Occipitoaxial Ligament Complex
Alar ligaments (2)
Apical
ligament
Posterior cutaway view
Occipitoaxial
ligament
Posterior view

46. Lower Cervical, Thoracic,
and Lumbar Ligaments
•Extending from the axis (C2)
anteriorly to the sacrum.
•Is broader at the level of each
vertebral body than at the level of the
discs where the fibers adhere to the
annulus fibrosus.
•Attaches to each vertebral body
superiorly and inferiorly at the levels of
the end plates.
Anterior Longitudinal
Ligament (ALL)

47. Intertransverse
ligaments
Costal
ligaments
Lower Cervical, Thoracic,
and Lumbar Ligaments
The INTERTRANSVERSE
LIGAMENTS extend from the
inferior surface of the entire
length of the transverse process
to the superior surface of the
adjacent transverse process.
The COSTAL LIGAMENTS
connect the heads of the ribs to
the vertebrae.

48. Posterior longitudinal ligament
Lower Cervical, Thoracic,
and Lumbar Ligaments
POSTERIOR LONGITUDINAL
LIGAMENT (PLL)
• Is weaker than the ALL.
• It runs from the axis (C2) caudally to
the sacrum.
•The PLL is narrow at the levels of the
vertebrae, but the fibers extend laterally at
the disc levels. These fibers may help to
contain herniated disc material.
•Like the ALL, the PLL is attached to
the vertebra at the superior and inferior
margins, and to the annular fibers of the
intervertebral disc.

49. Interspinous
ligament
Ligamentum
nuchae
Lower Cervical, Thoracic,
and Lumbar Ligaments
The INTERSPINOUS
LIGAMENT connects each adjacent
spinous process.
In the cervical spine the
interspinous ligament becomes part
of the LIGAMENTUM NUCHAE , that
extends cranially to insert into the
occiput.

50. The SUPRASPINOUS
LIGAMENT is a very strong band
connecting the tips of
contiguous spinous processes. It
extends from C7 to the sacrum.
Supraspinous
ligament
Ligamentum
nuchae
Lower Cervical, Thoracic,
and Lumbar Ligaments
Above C7 these fibers are
part of the LIGAMENTUM
NUCHAE.

51. Ligamentum
flavum
Lower Cervical, Thoracic,
and Lumbar Ligaments
LIGAMENTUM FLAVUM
Also called the YELLOW
LIGAMENT
Consists of elastic fibers
oriented vertically that extend from
the anterior inferior surface of the
lamina above to the superior
posterior surface of the lamina
below.
The ligamentum flavum tends to
thicken as it progresses down the
spine, beginning at the axis (C2)
and extending to the sacrum.

52. The ILIOLUMBAR LIGAMENTS
extend from the transverse
processes of L4 and L5 to the iliac
crest.
Iliolumbar
ligaments
Anterior View Posterior View
Lumbosacral Ligaments

53. Lumbosacral Ligaments
Anterior View
Lumbosacral
ligaments
The LUMBOSACRAL
LIGAMENT is a thick, fibrous band
that extends from the anterior,
inferior aspect of the transverse
process of L5 to the lateral surface
of the sacrum.

54. Sacroiliac Ligaments
Short sacroiliac
ligaments
Posterior View
Long sacroiliac
ligaments
The SACROILIAC LIGAMENTS are
as follows:
•short sacroiliac ligaments:
composed of horizontal fibers
extending from the sacrum to
the posterior part of the iliac
bone
•long sacroiliac ligaments:
composed of fibers extending
vertically from the sacrum to
the posterior superior iliac
spine

55. Posterior Spinal Muscle Groups
Iliocostalis
The superficial posterior
muscles are collectively called the
ERECTOR SPINAE, comprising three
groups:
Longissimus
Spinalis
Erector
Spinae

56. Posterior Spinal Muscle Groups
semispinalis
capitis
semispinalis
cervicis
semispinalis
thoracis
The middle, or intermediate, muscle group of the spine
is called the SEMISPINALIS GROUP:

57. Posterior Spinal Muscle Groups
Multifidus
Intertransversarii
attachments
between spinous
processes
Rotatores
(longus and brevis)
Rotatores
cervices
Rotatores
thoracis
Rotatores
lumborum
Levatores costae
(longus and brevis)
The deep muscle layer
consists of the following
groups:

58. Arteries of the Cranial and Cervical Region
Foramen
lacerum
Vertebral
artery
Carotid
artery
Two VERTEBRAL
ARTERIES, one located on each
side the cervical vertebrae. These
arteries are branches of the right
and left subclavian vs. that exit from
aorta.
They ascend through the
transverse foramen of C6 through
C1,entering the skull through the
foramen magnum where they join
together to form the BASILAR
ARTERY.
Anterior to the cervical
vertebrae are the CAROTID
ARTERIES, which ascend through
the FORAMEN LACERUM and
join with the vertebral arteries to
form the CIRCLE OF WILLIS.

59. Arteries of the Cranial and Cervical Region
Vertebral
arteries
Basilar
artery
Circle of Willis
Internal
carotid
arteries

60. Arteries of the Thoracic and Lumbosacral Regions
Vertebral
artery
Aortic arch
Ascending
aorta
Descending
aorta
Thoracic
segmental
arteries
Abdominal
aorta
Bifurcation
of the aorta Lumbar
segmental
arteries
External iliac
artery (left &
right) Internal
iliac artery
(left & right)
Femoral artery
(left & right)

61. Segmental Arteries
At each vertebral level from T4 to the sacrum, a pair
of SEGMENTAL ARTERIES branches posteriorly from
the aorta to supply blood to the vertebral body, posterior
elements, spinal cord, and costal structures.
Aorta
Segmental
arteries
Intercostal
artery
Spinal
branch
Anterior spinal
artery
Posterior
branch
Anastomoses

62. The most important venous structures in the
cervical spine are the internal and external
JUGULAR VEINS. The internal jugular veins follow
a path similar to the carotid arteries. They should
always be considered during any anterior cervical
spine procedure.
Veins of the Cervical and Thoracic Region
External
jugular
Anterior
jugular
Internal
jugular

63. Veins of the Thoracic and Lumbar Region
Internal
jugular
Superior
vena cava
Azygos
vein
Thoracic
segmental
veins
Hemiazygos
vein
Lumbar
segmental
veins
Inferior
vena cava
Common
iliac veins

64. Batson’s Plexus
The AZYGOS SYSTEM is a large
network of veins draining blood from
the intestines and other abdominal
organs back to the heart. The
segmental veins drain into the azygos
vein located on the right side of the
abdomen, or into the hemiazygos vein
located on the left side.
The azygos system also
communicates with a valveless
venous network known as BATSON’S
PLEXUS. When the vena cava is
partially or totally occluded, Batson’s
plexus provides an alternate route for
blood return to the heart.
The vessels of Batson’s plexus
may be referred to as epidural veins
Batson’s
plexus

65. Batson’s Plexus
Because of the azygos
system, patient positioning is
very important in posterior
lumbar spine surgery.
The patient’s abdomen
should always hang free and
without abdominal pressure. An
increase in pressure will
diminish flow through the
azygos system and the vena
cava. This results in an increase
of venous flow into Batson’s
plexus with a corresponding
increase of blood loss.
Batson’s
plexus

66. Spinal Nerve Structures
Spinal Cord
•Contained in epidural space
•Network of sensory and motor
nerves
•Firm, cord-like structure
Foramen
magnum
•Extends from foramen magnum to
L1
•Terminates at the
conus medularis
•The cauda equina begins
below L1
•Filum terminale extends from
conus medularis to the coccyx
Conus
medularis
Cauda
equina

67. Meninges
Dura mater
Subdural space
Arachnoid
layer
Subarachnoid
space: filled
with CSF
Pia mater
Within the spinal canal, the spinal cord is surrounded by the
EPIDURAL SPACE, filled with fatty tissue, veins, and arteries. The fatty
tissue acts as a shock absorber.
The spinal cord is covered by MENINGES which has three layers.

68. Spinal Nerve Topography
31 pairs of spinal nerves
•8 cervical
•12 thoracic
•5 lumbar
•6 sacrococcygeal

69. Spinal Nerves
Spinal
cord
Epidural
space
Dura mater and
Arachnoid layers
Subarachnoid
space
Dorsal root
Ventral
root
Dorsal root
ganglion
Peripheral
nerve

70. Autonomic Nervous System
Independent of voluntary control.
Controls glandular and cardiac
function and smooth muscle such as
that found in the digestive tract.
There are two components:
sympathetic
parasympathetic
The control centers of both
systems are located outside the
spinal cord in structures called
GANGLIA.

71. Autonomic Nervous System
The SYMPATHETIC NERVOUS
SYSTEM consists of a series of ganglia
extending from the skull to the coccyx,
lying on each side of the vertebral bodies.
These aligned ganglia look like a chain at
each side of the spine and are often
referred to as the sympathetic nerve chain.
Injury to the sympathetic nerve chain
in the lumbar spine may result in
genitourinary problems for the patient.
Each sympathetic ganglion has fibers
that join to the adjacent spinal nerve.
The PARASYMPATHETIC
NERVOUS SYSTEM has ganglia located
close to the organs they control.

72. Thank You!Thank You!