PMR PG Teaching

1. ANATOMY OF SPINE -1
PMR PG Teaching- August 2016
Dr. Jimy Jose
Resident, Deptt. Of PMR
SMS Medical College, Jaipur

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.

4. • The thoracic and sacral segments
maintain kyphotic postures found in
utero- attachment points for the rib cage
and pelvic girdle.
• The cervical and lumbar segments
develop lordosis as erect posture is
acquired.

5. A TYPICAL VERTEBRA
 anterior body and a posterior arch - enclose the vertebral canal or
foramen through which runs the spinal cord.
 The neural arch - two cylindrical pedicles laterally and two flattened
laminae posteriorly which unite to form the spinous process.
 To either side of the arch - transverse process and superior and
inferior articular processes -articulate with adjacent vertebrae to form
synovial joints.

6. A TYPICAL VERTEBRA
• spinous process: posteriorly and inferiorly from junction of the
two laminae , it’s a site for muscle and ligament attachment.
• transverse process : posterolaterally from the junction of the
pedicle and lamina ; site for articulation with ribs in the thoracic
region.
• superior and inferior articular processes : Also from the region
where the pedicles join the laminae ; articulate with the inferior
and superior articular processes, respectively, of adjacent
vertebrae.

7. • articular processes : accounts for the degree of flexion,
extension, or rotation possible in each segment of the vertebral
column.
• spinous and transverse processes : levers for the numerous
muscles attached to them.
• The length of vertebral column : averages 72 cm in men
and 7 to 10 cm less in women.

8. ANATOMY OF SPINAL JOINTS
 vertebrae are connected by joints between the neural
arches ; and between the bodies.
 total of six joints :
 The joints between the neural arches :zygapophyseal
joints or facet joints.
 inferior articular process of one vertebra and the
superior articular process of the vertebra immediately
caudal.
 synovial joints with surfaces covered by articular
cartilage, a synovial membrane, and a joint capsule
enclosing them.
 four synovial joints (two above and two below)
 Interbody joints contain intervertebral discs.
 two symphyses (one above and one below).
 found throughout the vertebral column except between
the first and second cervical vertebrae.
 The discs are designed to accommodate movement,
weight bearing, and shock.

9. A TYPICAL VERTEBRA

10. INTERVERTEBRAL FORAMINA
intervertebral foramen is formed by :
1. inferior vertebral notch on the pedicle
of the vertebra above
2. superior vertebral notch on the
pedicle of the vertebra below.
The foramen is bordered:
posteriorly by the zygapophysial joint
between the articular processes of the two
vertebrae; and
anteriorly by the intervertebral disc and
adjacent vertebral bodies.
The foramina allow structures, such as
spinal nerves and blood vessels, to pass
in and out of the vertebral canal.
 The anterior and posterior nerve roots
of a spinal nerve unite within these
foramina with their coverings of dura
to form the segmental spinal nerves.

11. CERVICAL VERTEBRAE :
 small size
 foramen transversarium in trough transverse process for the
passage of the vertebral artery and veins
 verterbral artery passes through the transverse process of C1 to C6 ,
not C7.
 the vertebral body is short in height ,square shaped when viewed
from above -- concave superior surface and a convex inferior
surface
 spinous process is short and bifid
 vertebral foramen is triangular
and large

12. ATYPICAL CERVICAL
VERTEBRAE
• The first , second and seventh cervical vertebrae
• The first and second cervical vertebrae- the atlas and axis-
specialized to accommodate movement of the head.
• The seventh cervical vertebrae – (vertebrae prominens )
named cos it had the longest spinous process, and its not
bifid .

13.  Vertebra CI (the atlas) –
• lacks a vertebral body or a spinous
process .
• ring-shaped
• articular surfaces on its upper surface for
articulation with occipital condyles (
Atlanto-occipital joints)
• articular surfaces on its lower surface for
articulation with the axis (atlanto-axial joint)
• In fact, the vertebral body of CI fuses onto
the body of CII during development to
become the dens of CII.
As a result, there is no intervertebral disc
between CI and CII.

14. ATLAS AND AXIS
• The atlanto-occipital joint (synovial
joint) allows the head to nod up and
down on the vertebral column.
• The dens is held in position by a
strong transverse ligament of atlas
posterior to it and acts as a pivot that
allows the atlas and attached head to
rotate on the axis, side to side.
• The transverse processes of the atlas
are large and protrude further laterally
than those of the other cervical
vertebrae

15. • The two superolateral
surfaces of the dens -
attachment sites for strong
alar ligaments.
• one on each side, which
connect the dens to the
medial surfaces of the
occipital condyles.
• alar ligaments check
excessive rotation of the head
and atlas relative to the axis.

16. THORACIC VERTEBRAE• The twelve thoracic vertebrae – characterized by articulation with ribs.
 two partial facets on each side of the vertebral body--- for articulation with ribs
 superior costal facets-head of its own rib
 inferior costal facets - head of the rib below .
• The superior costal facet is much larger than the inferior costal facet.
• Each transverse process also has a facet (transverse costal facet) for
articulation with the tubercle of its own rib.
• The vertebral body - heart-shaped when viewed from above
• vertebral foramen is circular.

17. LUMBAR VERTEBRAE
 distinguished by their large size
 The vertebral body is cylindrical
 vertebral foramen is triangular and larger than in the thoracic
vertebrae.
• The transverse processes are generally thin and long, with the
exception of those on vertebra LV, which are massive and cone-shaped
for the attachment of iliolumbar ligaments to connect the transverse
processes to the pelvic bones.

18. THE SACRUM
• The sacrum is a single bone : five fused sacral vertebrae.
• It is triangular in shape with the apex pointed inferiorly, and is curved
• concave anterior surface and convex posteriorly
• It articulates above with vertebra LV and below with the coccyx.
• It has two large L-shaped facets, one on each lateral surface, for articulation with the pelvic
bones to form the sacroiliac joints
• The posterior surface of the sacrum has four pairs of posterior sacral foramina,
• anterior surface has four pairs of anterior sacral foramina
• for the passage of the posterior and anterior rami, respectively, of S1 to S4 spinal nerves.
• Sacral Promontory : anterior upper margin of first sacral vertebra- forms posterior margin of
pelvi

20. SACRAL CANAL CONTAINS-
• Anterior and posterior roots of sacral and coccygeal spinal
nerves
• Filum terminale
• Fibrofatty material
• Lower part of subarachnoid space down as far as lower
border of second sacral vertebra.

21. COCCYX
• small triangular bone - articulates with the inferior end of the
sacrum
• represents three to four fused coccygeal vertebrae .
• It is characterized by its small size and by the absence of
vertebral arches and therefore a vertebral canal.

22. 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.

23. 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.

24. POSTERIOR SPACES BETWEEN VERTEBRAL ARCHES

25. 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.
 Degenerative changes in anulus fibrosus - herniation of the nucleus
pulposus.
• Posterolateral herniation :impinge on the roots of a spinal nerve in the
intervertebral foramen.

26. INTERVERTEBRAL DISC

27. 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.
 Tectorial membrane : The upper part of the
posterior longitudinal ligament that connects CII to
the intracranial aspect of the base of the skull

28. LIGAMENTA FLAVA
• on each side, pass between the laminae of adjacent vertebrae
• thin, broad
• form part of the posterior surface of the vertebral canal.
• 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

29. SUPRASPINOUS LIGAMENT AND LIGAMENTUM NUCHAE
• The supraspinous ligament:
along the tips of the vertebral
spinous processes from
vertebra CVII to the sacrum
• From vertebra CVII to the skull,
the ligament is called the
ligamentum nuchae.

30. THE LIGAMENTUM NUCHAE
• is a triangular,
• sheet-like structure in the median sagittal plane:
• base :attached to the skull, from the external occipital protuberance to the
foramen magnum
• apex :attached to the tip of the spinous process of vertebra CVII
• the deep side of the triangle is attached to the posterior tubercle of vertebra
CI and the spinous processes of the other cervical vertebrae.
• supports the head and resists flexion and facilitates returning the head to
anatomical position.

31. INTERSPINOUS
LIGAMENTS
• pass between adjacent vertebral
spinous processes
• They attach from the base to the
apex of each spinous process and
blend with the supraspinous
ligament posteriorly and the
ligamenta flava anteriorly on each
side.

32. ANATOMY OF SPINAL CORD AND NERVES
• The spinal cord is shorter than the vertebral
column
• terminates as the conus medullaris at the L2
vertebra in adults and the L3 vertebra in
neonates.
• From the conus, a fibrous cord called the
filum terminale extends to the dorsum of the
first coccygeal segment.
• The spinal cord has enlargements in the
cervical and lumbar regions that correlate
with the brachial plexus and lumbar plexus

33. • The spinal cord is enclosed
in three protective
membranes—the pia,
arachnoid, and dura mater.
• The pia and arachnoid
membranes are separated
by the subarachnoid space,
which contains
cerebrospinal fluid.

34. • deep longitudinal fissure called the
anterior median fissure in the
midline anteriorly
• shallow furrow called the posterior
median sulcus on the posterior
surface
• posterolateral sulcus on each side
of the posterior surface marks where
the posterior rootlets of spinal nerves
enter the cord.

35. SPINAL NERVES
 31 pairs of spinal nerves
attached by the anterior (
motor ) and posterior
(sensory ) roots
 Each root is attached by
a series of rootlets,
which extend the whole
length of the
corresponding segment
of the cord.
 Each posterior nerve
root possesses a
posterior/dorsal root
ganglion, the cells of
which give rise to
peripheral and central
nerve fibers.

36.  Each spinal nerve divides, as it emerges from an intervertebral
foramen, into two major branches:
1. a small posterior ramus
2. larger anterior ramus
 posterior rami innervate only intrinsic back muscles -
 anterior rami innervate most other skeletal muscles of the body,
including those of the limbs and trunk.
• form the major somatic plexuses (cervical, brachial, lumbar, and
sacral) of the body.
• Major visceral components of the PNS (sympathetic trunk and
prevertebral plexus).

40. NOMENCLATURE OF SPINAL
NERVES

41. RELATIONSHIP BETWEEN SPINAL
CORD AND VERTEBRAL SEGMENTS
The spinal cord has 31 segments: named according to their position with
respect to associated vertebrae:
■■ 8 cervical (C) -C1 to C8
■■ 12 thoracic (T)-T1 to T12
■■ 5 lumbar (L)- L1 to L5
■■ 5 sacral (S)- S1 to S5
■■ 1 coccygeal (Co)- Co
The vertebral column consists of 33 vertebrae:
■■ 7 cervical
■■ 12 thoracic
■■ 5 lumbar
■■ 5 sacral
■■ 4 coccygeal

42. RELATIONSHIP OF SPINAL CORD SEGMENTS TO VERTEBRAL NUMBERS

43. The sensory component of each spinal nerve is
distributed to a dermatome, a well-defined
segment of the skin
The first cervical and coccygeal nerves
typically have no dorsal root so do not have any
dermatomal representation.
The skeletal musculature innervated by motor
axons in a given spinal root is called a myotome.

44. GRAY MATTER
• On cross section, the gray matter is seen
as an H-shaped pillar
• anterior and posterior gray columns, or
horns, united by a thin gray commissure
containing the small central canal
• The amount of gray matter - is related to
the amount of muscle innervated at that
level.
• size is greatest within the cervical and
lumbosacral enlargements of the cord,
which innervate the muscles of the upper
and lower limbs, respectively

45. WHITE MATTER
• surrounds the gray matter and is rich in nerve cell processes
• form large bundles or tracts that ascend and descend in the
cord to other spinal cord levels or carry information to and from
the brain.

46. TRACTS OF THE SPINAL
CORD

48. • tracts of ascending (sensory)
and descending (motor) nerve
fibers. Are arranged with
cervical tracts located
centrally
• and thoracic, lumbar, and sacral
tracts located progressively
peripheral.
• This accounts for the clinical
findings of central cord
syndrome and syrinx.

49. BLOOD SUPPLY OF THE SPINAL
CORD- ARTERIES
The spinal cord receives its arterial supply from three small
arteries:
the two posterior spinal arteries
anterior spinal artery.
These longitudinally running arteries are reinforced by small
segmentally arranged arteries that arise from arteries outside
the vertebral column and enter the vertebral canal through the
intervertebral foramina.
These vessels anastomose on the surface of the cord and
send branches into the substance of the white and gray
matter.

51. POSTERIOR SPINAL ARTERIES
• The posterior spinal arteries arise either directly from the
vertebral arteries inside the skull or indirectly from the
posterior inferior cerebellar arteries.
• Each artery descends on the posterior surface of the spinal
cord close to the posterior nerve roots and gives off branches
that enter the substance of the cord.
• The posterior spinal arteries supply the posterior one-third of
the spinal cord.
• The posterior spinal arteries are small in the upper thoracic
region, and the first three thoracic segments of the spinal cord
are particularly vulnerable to ischemia should the segmental or
radicular arteries in this region be occluded.

52. ANTERIOR SPINAL ARTERY
The anterior spinal artery is formed by the union of two arteries,
each of which arises from the vertebral artery inside the skull.
The anterior spinal artery then descends on the anterior surface
of the spinal cord within the anterior median fissure
Branches from the anterior spinal artery enter the substance of
the cord and supply the anterior two-thirds of the spinal cord.
In the upper and lower thoracic segments of the spinal cord, the
anterior spinal artery may be extremely small.
Should the segmental or radicular arteries be occluded in these
regions, the fourth thoracic and the first lumbar segments of the
spinal cord would be particularly liable to ischemic necrosis.

53. SEGMENTAL SPINAL
ARTERIES
• At each intervertebral foramen, the longitudinally running
posterior and anterior spinal arteries are reinforced by
small segmental arteries on both sides.
• The arteries are branches of arteries outside the vertebral
column (deep cervical, intercostal, and lumbar arteries).
• Having entered the vertebral canal, each segmental spinal
artery gives rise to anterior and posterior radicular arteries
that accompany the anterior and posterior nerve roots to
the spinal cord.

54. • Additional feeder arteries enter the vertebral canal and
anastomose with the anterior and posterior spinal arteries;
• however, the number and size of these arteries vary
considerably from one individual to another.
• One large and important feeder artery, the great anterior
medullary artery of Adamkiewicz, arises from the aorta in
the lower thoracic or upper lumbar vertebral levels;
• it is unilateral and, in the majority of persons, enters the
spinal cord from the left side.
• The importance of this artery lies in the fact that it may be
the major source of blood to the lower two-thirds of the
spinal cord.

56. VEINS OF THE SPINAL CORD
The veins of the spinal cord drain into six tortuous
longitudinal channels that communicate superiorly within the
skull with the veins of the brain and the venous sinuses. They
drain mainly into the internal vertebral venous plexus.

57. REFERENCES
•Grays Anatomy
•Snell’s clinical Neuroanatomy
•Snell’s Anatomy

58. -Thank you