Vascular Anatomy of Spinal Cord

1. THE VASCULAR
ANATOMY OF
THE VERTEBRO-SPINAL
AXIS

2. INTRODUCTION
• Adamkiewicz – 1881 – published the first extensive study on the
blood vessels of the spinal cord
• Kadyi – 1889 - did a study on 29 human spinal cords
• Only sources of accurate detailed information and basic terminology
on this subject up until the late 1930s

3. • Improvements in endovascular and microsurgical techniques
• More effective treatment for vascular lesions of the spinal cord
• Thorough knowledge of the vascular anatomy of the spine and spinal
cord
• Prerequisite for understanding the pathophysiology of spinal vascular
lesions
• Planning safe surgical and endovascular interventions

4. EMBRYOLOGY
• Vascular supply of the spinal axis - Systematically determined during
the first few weeks of development
• 31 somites are formed, each receiving one individual pair of
segmental arteries from the dorsal aorta
• Paired segmental arteries - ultimately support a functionally distinct
vascular compartment
• Thoracolumbar spinal vasculature retains the classically paired
segmental arrangement into adulthood

5. • Cervical spine vasculature - considerable modification of the
segmental disposition
• Three dominant vascular channels: the anterior cervical artery,
vertebral artery, deep cervical artery
• Sacral region –
• paired lateral sacral arteries arise from the internal iliac arteries
• distal dorsal aorta regresses to become the middle sacral artery,
which anastomoses with lateral sacral arteries

6. VASCULAR SUPPLY TO
THE SPINE, SPINAL DURA,
AND PARASPINAL
MUSCULATURE

7. SEGMENTAL ARTERIES
• Thoracic and upper lumbar spine
• Originate in pairs from the descending aorta
• Above T3 - several segmental arteries arise from a common origin
• Supreme intercostal artery/superior intercostal artery
• commonly a branch of the costocervical trunk or the aortic arch, and
rarely from the vertebral artery
• Provides supply to the upper thoracic region

8. 1. Basilar artery
2. Vertebral artery
3. Anterior spinal artery
4. Posterior spinal artery
5. Radiculo-pial artery
6. Anterior radiculo-medullary
artery
7. Thyro-cervical trunk
8. Cervical ascending artery
9. Costocervical trunk
10. Deep cervical artery
11. Supreme intercostal artery

9. • Below T3- typically one pair of segmental arteries at each level
• Posterior intercostal arteries (nine pairs)
• Subcostal arteries (one pair)
• Lumbar segmental arteries (four pairs)
• Extensive anastomoses between segmental arteries

10. 1) Basilar artery
2) Vertebral artery
3) Anterior spinal artery
4) Posterior spinal arteries
5) Anterior radiculomedullary artery
6) Ascending cervical artery
7) Deep cervical artery
8) Subclavian artery
9) Posterior radiculomedullary artery
10) Segmental arteries (posterior
intercostal arteries)
11) Great anterior radiculomedullary
artery or artery of Adamkiewicz
12) Segmental arteries (lumbar arteries)
13)Rami cruciantes

11. • Segmental arteries are named by the level they supply and not by the
level from which they originate
• DSA – correctly identify the level of a given segmental artery – 2
methods
• 1) By identifying the hemivertebral blush evident after injection of
contrast material
• 2) Use bony landmarks
• Thoracic spine - each segmental artery is named according to the rib
under which it courses

13. • Travel along the surface of the vertebral bodies
• short branches - supply the anterior and lateral vertebral bodies
• divide into three major trunks:
• (i) lateral or ventral - posterior intercostal or lumbar artery
• (ii) middle or dorsal - muscular and cutaneous branches)
• (iii) medial or spinal

14. (1)Posterior spinal arteries
(2)Anterior spinal artery
(3) Great anterior
radiculomedullary artery
or artery of Adamkiewicz
(4) Medial musculocutaneous
branch
(5) Lateral musculocutaneous
branch
(6) Posterior
radiculomedullary artery
(7) Retrocorporeal arteries
(8) Spinal trunk
(9) Middle (dorsal) trunk
(10) Lateral (ventral) trunk

15. • Spinal trunk- enters the spinal canal at the intervertebral foramen
• divides into
• (a) ventral and dorsal divisions- retro-corporeal and pre-laminar
arteries
• supply the vertebral and ligamentous structures and, to a lesser
extent, the dura mater
• (b) radicular artery - supplies the dura, nerve root and spinal cord

16. (1)Posterior spinal arteries
(2)Anterior spinal artery
(3) Great anterior
radiculomedullary artery
or artery of Adamkiewicz
(4) Medial musculocutaneous
branch
(5) Lateral musculocutaneous
branch
(6) Posterior
radiculomedullary artery
(7) Retrocorporeal arteries
(8) Spinal branch
(9) Middle (dorsal) branch
(10) Lateral (ventral)branch

17. INTRASPINAL ANASTOMOSES
• Extensive anastomoses between segmental arteries with important
connections both above and below a given level, as well as
contralaterally
• Between successive vertebral levels - along a longitudinal axis
• Transverse anastomoses across the midline – both dorsal and ventral
to the dural sheath
• Form an extradural ring- supply the adjacent bony and dural
structures

18. RETROCORPOREAL COLLATERAL
ARCADE
• Spinal trunk arteries entering the epidural space anteriorly - divide
into a hexagonal branching pattern
• Recognizable angiographically - retrocorporeal collateral arcade
• Vascularizes the posterior aspect of vertebral body
• Form transverse and longitudinal collateral interconnections within
the anterior epidural space

20. EXTRASPINAL ANASTOMOSES
• Longitudinal anastomoses between the extraspinal branches of
consecutive segmental arteries
• Ventrally - divided into anterior, anterolateral, and pretransverse
groups
• Dorsally - between successive dorsal muscular branches adjacent to
the spinous processes
• Development of dominant longitudinal extraspinal anastomoses
throughout the cervical levels establishes the ascending cervical,
vertebral, and deep cervical arteries on which the vascularization of
the cervical spine depends

21. • divided into four vascular territories at each vertebral level
• (1) Segmental arteries - anterolateral aspect of the vertebral body
before giving off the dorsal spinal trunk
• (2) Ventral division of the dorsal spinal artery - structures of the spinal
canal, including the bony elements, epidural space, dura, and
contents of the thecal sac
• (3) Dorsal division of the dorsal spinal artery - middle and lateral
muscular branches to the dorsal muscular groups
• (4) Thoracic and lumbar segmental artery also supplies lateral
muscular branches

22. VASCULAR SUPPLY TO
THE SPINAL CORD

23. • Arterial architecture is organized around
• Horizontal axes - radicular arteries
• anastomose with
• Longitudinal axes - anterior, and posterior spinal arteries
• Can also be divided into three different networks
• extraspinal radicular arteries
• perispinal arteries - forming a pial network around the longitudinal
axes
• intraspinal arteries

24. • Density of arterial supply - varies according to each level
• Cervical and lumbosacral segments - richly supplied
• Thoracic segment has few arteries

25. 1. Basilar artery
2. Vertebral artery
3. Anterior spinal artery
4. Posterior spinal artery
5. Radiculo-pial artery
6. Anterior radiculo-medullary artery
7. Thyro-cervical trunk
8. Cervical ascending artery
9. Costocervical trunk
10. Deep cervical artery
11. Supreme intercostal artery
12. Intercostal artery
13. Arteria radicularis magna (of Adamkiewicz)
14. L5 anterior radiculo-medullary artery (of
Desproges-Gotteron)
15. Anterior arterial spinal axis
16. Posterior arterial spinal axis

26. RADICULAR ARTERIES
• Branch of segmental artery
• Each radicular artery penetrates the spine - following the spinal nerve
and then its roots
• Arterial desegmentation - occurs throughout the development
• Certain arteries regress and others hypertrophy, resulting in the adult
disposition
• Theoretical figure of 62 radicular arteries is thus never reached

27. • The radicular arteries have been classed into three groups:
• Radiculoradial arteries
• Radiculopial arteries
• Radiculomedullary arteries

28. RADICULORADIAL
• Disappear in the roots before reaching the pia mater and the spinal
cord
• Supply the dura and nerve roots
• Not involved in supplying blood to the spinal cord

29. RADICULOPIAL ARTERIES
• Reach the spinal cord pial network
• Participate in the pial network, which gives off radial perforators
centripetally to the spinal cord
• Participate in the posterior arterial axis
• Do not participate in the supply of the anterior spinal axis

31. RADICULOMEDULLARY ARTERIES
• Supply the spinal cord
• arterial supply to the spinal cord originates from only a few of the
segmental arteries
• contribute in both the segmental and longitudinal supply
• Divided into anterior and posterior radiculomedullary arteries - based
on whether they supply the anterior or posterior spinal arteries,
respectively
• Anterior - participating in the anterior spinal axis – average - 6
• Posterior - participating in the posterior pial network– 11 - 16

32. (1)Posterior spinal arteries
(2)Anterior spinal artery
(3) Great anterior
radiculomedullary artery or
artery of Adamkiewicz
(4) Medial musculocutaneous
branch
(5) Lateral musculocutaneous
branch
(6) Posterior
radiculomedullary artery
(7) Retrocorporeal arteries
(8) Spinal branch
(9) Middle (dorsal) branch
(10) Lateral (ventral)branch

33. ANTERIOR RADICULOMEDULLARY
ARTERIES
• Average number - 6 (range 5 - 10)
• Caliber - varies
• Smaller - thoracic spinal level
• Larger - cervical and lumbar segments
• Cervical region - 2 - 3 anterior radiculomedullary arteries, most
important supply to the cervical ASA
• Artery of the cervical enlargement
• Arises from vertebral or cervical arteries at the C5 or C6 level
• More often a branch of the deep cervical artery and usually
accompanies the C6 nerve root

34. Artery of cervical enlargement (arrow)
supplying the anterior spinal artery

35. • The cervical cord is fed by the numerous anterior radiculomedullary
arteries of varied origin:
• vertebral
• ascending cervical - midcervical cord (C4 - C6)
• deep cervical arteries – C7 and C8
• Lesser degree from the ascending pharyngeal and occipital artery
• Ensure sure a rich supply of arterial blood
• All of these arteries need to be meticulously explored for complete
angiographic evaluation of the vascular supply to the cervical cord

36. 1. Sub-clavian artery
2. Common carotid artery
3. Internal carotid artery
4. External carotid artery
5. Vertebral artery
6. Thyro-cervical trunk
7. Costocervical trunk
8. Cervical ascending artery
9. Deep cervical artery
10. Occipital artery
11. Basilar artery
12. Anterior spinal artery
13. Anterior radiculo-medullary
artery
14. Anterior arterial spinal axis

37. ARTERY OF ADAMKIEWICZ
• Lumbar region - one of the anterior radiculomedullary arteries is
particularly developed
• Artery of the lumbar enlargement (arteria radicula magna of
Adamkiewicz)
• Originates most often between levels T9 and T12
• Diameter of 0.5 - 1.0 mm
• In 80% of cases, it is found in the left side

38. • Angiographically, forms the classic ‘hairpin’ loop when it reaches the
ASA
• Gives off a thin ascending branch and a larger descending branch
• Rare cases - anterior radiculomedullary artery accompanying the L5
or S1 root can participate in the supply of blood to the conus
medullaris - Desproges–Gotteron artery

39. Selective catheter spinal angiography
(frontal view)
depicts the typical ‘hairpin’ ascending
branch of the artery of
Adamkiewicz (arrow) which supplies the
anterior spinal artery(arrowheads).
The hemivertebral blush is noted in (A),
confirming the
midline position of the anterior spinal
artery

41. POSTERIOR RADICULOMEDULLARY
ARTERIES
• Vary in number between 10 and 20
• Caliber - much smaller than the anterior
• Difficult to clearly identify their course
• Divide into numerous branches in the pial network

42. SUPERFICIAL ARTERIAL SYSTEM OF
THE SPINAL CORD
• Surface of the cord - two arterial systems:
• (1) Longitudinal arterial trunks
• extend along the long axis of the spinal cord
• constituted by the anterior spinal artery and two posterior spinal
arteries
• (2) Pial plexus
• covers the periphery of the spinal cord

44. LONGITUDINAL ARTERIAL
TRUNKS

45. ANTERIOR SPINAL ARTERY
• Formed at the level of the foramen magnum
• Confluence of descending branches of the intracranial segments of
the vertebral arteries
• Join at the C 2 - 4 level
• Travels along the anterior sulcus of the spinal cord
• Descends to the conus medullaris
• Supplies the anterior two-thirds of the spinal cord tissue (including
the anterior horns, and the spinothalamic and corticospinal tracts)

47. • Varies in diameter over its length, in a manner matched to the
variable metabolic demands of the different spinal cord segments
• Thinnest in the thoracic cord and thickest in the region of the conus
• Due to its long course, requires additional arterial supply via anterior
radiculomedullary arteries - to maintain adequate blood flow to the
entire spinal cord
• Originates from three major regions:
• Cervicothoracic
• Midthoracic
• Thoracolumbar

48. • 2-3 anterior radiculomedullary arteries in the cervical region
• Main - artery of cervical enlargement
• Small radicular arteries supply the spinal cord in the upper and mid-
thoracic region - difficult to visualize angiographically
• Most important - artery radiculomedullaris magna/artery of
Adamkiewicz (AKA)
• Portions of the thoracic and upper lumbar spinal cord are extremely
vulnerable to ischemic compromise
• Minimal collateral supply to the spinal cord inferior to the junction of
the AKA and ASA

49. • ASA continues caudally past the conus as an insignificant branch to
the filum terminale
• At the conus - anastomoses with terminal segments of the posterior
spinal arteries
• Forming an arterial ‘‘basket’’ - ‘rami cruciantes’ that surround the
conus

51. POSTERIOR SPINAL ARTERIES
• Two PSAs also originate at the level of the foramen magnum
• Ipsilateral vertebral or posterior inferior cerebellar arteries
• Posterolateral surface of the spinal cord
• Supplies the posterior third of the spinal cord, including the posterior
columns, dorsal gray matter and superficial dorsal aspect of the
lateral columns of the spinal cord

52. • Receives supply at various levels from the posterior
radiculomedullary arteries
• Eleven to 16 feeders contribute to the PSA at various levels through
the spine
• Largest posterior radiculomedullary artery often enters below the
level of the AKA

54. PIAL PLEXUS
• extensive arterial network on the entire surface of the spinal cord
formed by effective anastomoses between the ASAs and PSAs
• also referred to as the ‘vasocorona’
• consists of transverse and oblique branches from the ASAs and PSAs
• esponsible for supplying the periphery of the spinal cord
• Radially directed perforators (rami perforantes) - arise from the
surface vasocorona
• penetrate to a variable extent into the white matter of the spinal
funiculi

56. INTRINSIC ARTERIAL SYSTEM
• Supplies spinal cord parenchyma
• Organized around two large systems:
• Central (centrifugal) system - Sulcocommissural arteries
• originate from the ASAs and travel into the anterior median fissure
• supply the anterior two thirds of the cross-sectional area of the spinal
cord
• Peripheral (centripetal or vasocorona) system - Radial perforating
arteries – small perforators (rami perforantes)
• originate from the pial plexus, vascularizes the periphery of the spinal
cord

57. • ASA supplies approximately two-thirds of the cross sectional area of
the spinal cord
• anterior commissure, anterior horns, Clarke’s nucleus, anterior
portions of the fasciculi cuneatus and gracilis, corticospinal and
spinothalamic tracts
• PSAs distribute blood to the dorsal third of the spinal cord
• Corticospinal pathways are nourished by both systems

58. 1. Anterior arterial spinal axis
2. Posterior arterial spinal axis
3. Anterior radiculo-medullary artery
4. Pial arterial network
5. Sulco-commissural artery
6. Radial perforating arteries arising
from pial network
7. Radial perforating arteries arising
from posterior spinal axis
8. Anterior venous spinal axis
9. Posterior venous spinal axis
10. Sulco-commissural veins
11. Posterior intrinsic veins
12. Pial venous network
13. Peripheral intrinsic veins
14. Radicular vein

59. WATERSHED ZONES
• The anatomic distribution of spinal arteries establishes three
watershed zones:
• (1) along the longitudinal axis of the upper thoracic spinal cord
between the arteries of the cervical and lumbar enlargements
• (2) over the anterolateral surface of the cord between circumferential
pial branches of the anterior spinal artery and the posterior spinal
arterial arcade
• (3) along the gray/white junction between the intramedullary
territories of the central sulcocommisural arteries and the peripheral
rami perforantes

60. VENOUS DRAINAGE
• divided into three compartments:
• (1) intrinsic venous system – intramedullary veins, which drain the
spinal cord parenchyma
• (2) extrinsic venous networks of the spinal cord - superficial venous
plexus of perimedullary veins and two longitudinally oriented veins
(the posterior and anterior median spinal veins)
• valveless and empty by way of radicular veins
• (3) vertebral venous plexus

61. • vertebral venous plexus (Batson’s plexus) - three intercommunicating
divisions:
• (i) internal vertebral venous plexus (anterior and posterior) - passes
superiorly within the vertebral canal through the foramen magnum to
freely anastomose with the intracranial venous system
• (ii) the external vertebral venous plexus (anterior and posterior)
which surround the vertebral column
• (iii) the basivertebral veins which run horizontally within the vertebra

62. • Valveless system along the length of the spinal cord
• External vertebral venous plexus connects to the internal vertebral
venous plexus via the intervertebral veins
• Intervertebral veins - empty into segmental veins that drain into the
ascending lumbar and azygos venous systems
• The three azygos vessels in the thoracic spine are the azygos on the
right and the hemiazygos and accessory hemiazygos on the left
• All three drain into the superior vena cava

63. (1) Anterior median vein
(2) right deep cervical vein
(3) Left deep cervical vein
(4) right vertebral vein
(5) left vertebral vein
(6) subclavian vein
(7) internal jugular vein
(8) left brachiocephalic vein
(9) superior vena cava
(10) accessory hemiazygos vein
(11) Intercostal veins
(12) posterior radiculomedullary vein
(13) anterior radiculomedullary vein
(14) azygos vein
(15) hemiazygos vein
(16) lumbar veins
(17) vein of the filum terminale

64. References
• 1. Tatu L, Vuillier F, Moulin T. Anatomy of the circulation of the
brain and spinal cord. Handbook of clinical neurology. 2008;92:247–
281.
• 2. Becske T, Nelson PK. The Vascular Anatomy of the Vertebro-
Spinal Axis. Neurosurgery Clinics of North America. 2009
Jul;20(3):259–64.
• 3. Santillan A, Nacarino V, Greenberg E, Riina HA, Gobin YP,
Patsalides A. Vascular anatomy of the spinal cord. Journal of
neurointerventional surgery. 2011