Contents of vertebral canal and its applied aspects mbbs

Contents of vertebral canal and its applied aspects mbbs

2. 2
CONTENTS OF VERTEBRAL
CANAL AND ITS APPLIED
ASPECTS

5. (superior view)

8. Vertebral Column
V
Central bony pillar of the body.
V
Supports the skull, pectoral girdle, upper
limbs and the thoracic cage.
V
Within its cavity lie the spinal cord, the roots
of the spinal nerves, the covering-meninges.
V
Composed of 33 vertebrae: 7 cervical, 12
thoracic, 5 lumbar, 5 sacral, 4 coccygeal.
V
It is a flexible structure made up of
fibrocartilage called intervertebral discs.
8

9. VERTEBRAL CANAL V
The vertebral
canal is formed by
placing the
vertebra in a
sequence, that
their vertebral
foraminae are lie
one below the
other forming
continuous canal
9

10. The vertebral canal
T
The vertebral canalis bounded
anteriorlybythevertebralbodiesand
the intervertebral discs, each
covered by the posterior longitudinal
ligament, which is continuous from
the back of the body of the axis to
thesacrum.
10

11. The vertebral canal T
Posteriorly it is bounded
by the laminae,
ligamentaflava and the
arch of the vertebra.
T
The vertebral canal is
usually larger in the
cervical and lumbar
regions.
11

12. CONTENTS OF VERTEBRAL CANAL
V
The contents –from outwards;
V
1.epidural or extra dural space
V
2.thick dura mater or pachymenix
V
3.subdural capillary space
V
4.delicate arachnoid mater
V
5.wide subarachnoid space containing CSF
V
6.firm piamater .The Arachnoid and Piamater togeth er-leptomeninges
V
7.spinal cord and the caudaequina
V
8.Blood supply [arteries and lodges, valveless, dan gerous venous plexus
[Batsons]..
12

13. 13

14. CONTENTS OF THE VERTEBRAL CANAL
V
Spinal cord
V
is a cylindrical, grayish-
white structure, 42-45 cm
in length that begins above
the foramen magnum,
where it is continuous with
the medulla oblongata of
the brain.
V
It terminates below in the
adult at the level of the
lower border of the first
lumbar vertebra.
V
In the young child it is
relatively longer and ends
at the upper border of the
third lumbar vertebra.
14

15. BLOOD SUPPLY OF THE SPINAL CORD V
The spinal cord receives its
arterial supply from three
small, longitudinally running
arteries-the two posterior
spinal arteries branches of
posterior inferior cerebellar
arteries and the one anterior
spinal artery branch of
Vertebral artery,
15

16. 2
The veins of the spinal
cord drain into the
internal vertebral
venous plexus
16

17. Meninges of the spinal cord
1.
Dura mater
V
the most external membrane
and is a dense, strong, fibrous
sheet that encloses the spinal
cord and caudaequina.
V
Continuous above through
the foramen magnum with
the meningeallayer of dura
covering the brain.
V
Inferiorly, it ends on the filum
terminaleat the level of the
lower border of the second
sacral vertebra.
V
Epidural space-contains
loose areolartissue and the
internal vertebral venous
plexus.
17

18. 2. Arachnoid mater 2
a delicate impermeable
membrane covering the
spinal cord and lying
between the pia mater
internally and the dura
mater externally.
2
Separated from the dura
by the subdural space
that contains a thin film
of tissue fluid.
2
Separated from the pia
mater by a wide space,
the subarachnoid space,
which is filled with
cerebrospinal fluid.
2
Inferiorly , it ends on the
filum terminale.
18

19. 3. Pia mater 2
A vascular membrane
that closely covers the
spinal cord.
2
Below it fuses with the
filum terminale
2
The pia mater is
thickened on either side
between the nerve roots
to form the ligamentum
denticulum, which
passes laterally to be
attached to the dura.
19

20. LIGAMENTUM DENTICULATUM
V
These are the ribbon like
thickened bands of pia
mater,extending
laterally,piercing the arachnoid
and attached to the inner
surface of the duramater
V
The first teeth of denticulatum
lies at the level of foramen
magnum
V
The last between T12andL1
V
The lowest tooth is forked and
the posterior root of the L1 lie
at the outer prong of the fork
V
Serve as a guide in cardotomy
20

21. (anterior view)
dorsal n. root
ventral n. root
denticulate
ligaments

22. CONUS MEDULLARIS and CAUDA
EQUINA
V
The roots of the nerves
lumbar, sacral and
coccygeal leave through
appropriate numbered
intervertebral foramen
V
They together look like
a horse tail-cauda
equina
V
The terminal end of the
spinal cord-conus
medullaris.
22

23. CONUS-MEDULLARIS V
The Terminal end of
the spinal cord-conus
medullaris.
V
Adult-L1.
V
Children-L3

24. Conus medullaris and cauda equina
24

25. EPIDURAL SPACE
V
Lies between the spinal
duramater and the
periosteum and
ligaments lining the
vertebral canal
V
1.loose areolar
connective tissue V
2.semiliquid fat
V
3.spinal arteries
V
4.the internal vertebral
venous plexus.
25

26. Applied anatomy
V
Lumbar epidural
anaesthesia V
Between L3 and L4
spine n eedlecourse
through, skin, fat,
supraspinousand
interspinousligaments,
ligamentumflava,
epidural space.
V
This space is confirmed
by the fact that it is a
space with negative
pressure
26

27. CAUDAL EPIDURAL ANAESTHESIA
V
The needle is passed
through sacral hiatus
which lies equidistant
from the right and left
posterior superior iliac
spines and enters the
sacral canal
V
This space lies below
S2
27

28. SUBDURAL SPACE V
Is a potential space
between the duramater
and the arachnoid,
containing thin film of
serous fluid.
V
Permits movements of
dura over the arachnoid V
Continued for a short
distance on to the spinal
nerve
V
Free comunicationwith
the lymph spaces
around the nerves
28

29. Figure 12.29a
Cervical
enlargement
Dura and
arachnoid
mater
Lumbar
enlargement
Conus
medullaris
Cauda
equina
Filum
terminale
Cervical
spinal nerves
Lumbar
spinal nerves
Sacral
spinal nerves
Thoracic
spinal nerves
FILUM TERMINALE V
he filumterminale
("terminalthread"), is
a delicate strand of
fibrous tissue, about 20
cm in length,
proceeding downward
from the apex of the
conusmedullaris. It is
one of the
modifications of pia
mater.

30. SUB ARACHNOID SPACE
V
IS a wide space
between the piaand
the arachnoid filled
with CSF
V
Spinal sub arachnoid
space is wider then the
space around the brain
V
Widest below where it
encloses the caudae
30

31. Applied aspects
V
LUMBAR PUNCTURE:
V
Done through the
Intervertabraldisc
between L3 and L4 for
threupticand diagnostic
purpose.
V
In children-vertabrel
level-L1.
31

33. VERTABREL SYSTEM OF VEINS.

34. VERTESBRAL SYSTEM OF VEINS V
The vertebral venous
system –
valveless,complicated
network ,with
longitudinal pattren
V
Runs parallel to SVC
andIVCand
anastomoseswith
them
34

35. 35

36. 2
This network has three
intercommunicatiing
sub divisions
2
1,the epiduralplexuslies
in the vertebral canal
outside the durameter
2
Consists of 1. postcentral
2.pre laminar portion 2
This plexus drains the
structures in the
vertebral canal
2
Itself drained at regular
intervals by 2
Segmental veins-
vertebral,posterior
intercostal,lumbarand
lateral sacral .
36

37. 2
Plexus within the
veretebral bodies-
drains backwards into
the epidural plexus
2
Anterolaterally-into
the external vertebral
plexus
37

38. 3. External vertebral venous
plexus-
2
It consists of anterior vessels
lying in front of the vertebral
bodies
2
Posterior vessels on the back
of the vertebral arches and on
adjacent muscles-drained by
segmental veins
2
The sub occipital plexus of
veins lying in the sub occipital
triangle is a part of external
venous plexus
2
It receives the occipital veins
of the scalp –connected with
the transverse sinus by
emissary veins and drains into
the subclavian veins
38

39. BATSON’S PLEXUS
39
The azygossystem 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

40. 2
Communications-valveless vertebral system of
veins communicates 1.
Above with intracranial venous sinuses
2.
Below with the pelvic veins, portal vein and caval
system of veins
2
The veins are valvelessand so the blood can flow
in either direction
2
An increase in intra thoracic or intra abdominal
pressure due to coughing and straining may cause
blood to flow either upwards or downwards away
from heart
2
Such periodic changes in venous pressure are
clinically important
40

41. 2
There may possible spread of tumoursor
infection-eg: cells from pelvic, abdominal
thoracic and breast tumours-venous system -
lodge in the vertebra, spinal cord, skull or the
brain
2
Primary sites of tumourscausing secondariesin
vertebra are breast, prostate and kidney
2
Vertebral caries –tuberculousinfection with in
the veretebrae
41

46. 46