The document provides an overview of the anatomy and imaging features of the spine and spinal cord. It describes the basic anatomy of the vertebrae and spinal segments. Common spinal pathologies are summarized, including degenerative changes, trauma, infection, tumors and congenital abnormalities. For each condition, the document explains the imaging appearance and features to evaluate on radiographs, CT and MRI scans. Key anatomical structures and imaging signs are illustrated with examples.

1. Applied Cross-sectional Anatomy of
Spinal Cord
Tanat Tabtieang MD
Department of Anatomy
Faculty of Medicine
Chulalongkorn University

2. BASIC ANATOMY OF
THE SPINE AND SPINAL CORD
Applied Cross-sectional Anatomy of Spinal Cord

3. Anatomy of the Spine
• Cervical (7)
• Thoracic (12)
• Lumbar (5)
• Sacrum
• Coccyx

5. Anatomy of the Vertebrae
• Vertebral body
• Neural arch
– Pedicles
– Laminae
• Transverse process
– contains vertebral arteries in cervical
spine
– articulates with ribs in thoracic spine
• Spinous process

6. Anatomy of the Vertebrae
• Superior & Inferior articular
processes
– extend from the junction of the
pedicles and laminae
• Superior & Inferior articular facets
• Apophyseal joint (Facet joint,
Zygapophyseal joint)
• Pars interarticularis
– part of vertebra between the
processes
• Intervertebral foramen (Neural
foramen, exiting foramina)

11. Surface shaded CT reconstructions of lumbar vertebrae in axial and sagittal
views

12. Plain films of normal lumbar spine

13. Anatomy of the Intervertebral disc
• Annulus fibrosus
• Nucleus pulposus
• Cartilaginous end plate

14. Anatomy of the Spinal Cord

15. Anatomy of the Spinal Cord
• C3-C7
– Nerve roots are named according to the pedicle they PASS
OVER
– C5 nerve exits the spine through C4/C5 intervertebral
foramen
• Beyond C7
– Nerve roots are named according to the pedicle they PASS
UNDER
– T4 nerve exits the spine through T4/T5 intervertebral
foramen

17. Arterial Supplies of the Spinal Cord

18. Internal morphology of Spinal Cord

19. Dermatomes
Cervical segments
• C5 – Anterolateral shoulder
• C6 – Thumb
• C7 – Middle finger
• C8 – Little finger
Thoracic segments
• T1 – Medial side of arm
• T3 – 3rd-4th intercostal space
• T4 – Nipple
• T6 – Xiphoid process
• T10 – Navel
• T12 – Pubis
Lumbar segments
• L2 – Medial thigh
• L3 – Medial knee
• L4 – Medial ankle, Geart toe
• L5 – Dorsum of foot
Sacral segments
• S1 – Lateral foot
• S2 – Posteromedial thigh
• S3-5 – Perianal area

22. Motor power grading

23. << Normal T1-weighted and
T2-weighted MRI scan
>> Axial T2-weighted MRI through
L3/L4 disc space. The L3 nerve
roots are in exit foramina and L4
nerve roots have moved to the edge
of the dural sac in the lateral
recesses prior to exiting the spinal
canal at the level below

24. RADIOGRAPHIC SIGNS OF
SPINAL ABNORMALITY
Applied Cross-sectional Anatomy of Spinal Cord

25. Disc space narrowing
• Normally, the disc spaces are the
same height at all levels in C and T
spines. In L spine, the disc spaces
increase slightly in height going
down the spine.
• Reduction in intervertebral height
usually implies degenerative disc
disease.
• May associated with end plate
sclerosis and osteophytes
Disc space narrowing caused by
disc degenerative change
between L3 and L4. Note the
osteophytes and sclerosis of the
adjoining surfaces.

26. Collapse of vertebral bodies
• Metastases and myeloma
• Infection
• Osteoporosis
• Trauma
• Eosinophil granuloma
Metastasis
Complete collapse of the
vertebral body. The adjacent
vertebral discs are unaffected.
Disc space is usually normal.
Pedicle may be destructed.

27. >> Osteomyelitis
Narrow disc
space and
destruction of
surface of
adjacent
vertebrae. Pedicle
is intact.
>> Osteoporosis
Decrease bone
density with
collapse of
vertebral body
due to
compression
fracture. Disc
space is normal.
Pedicle is intact.
<< Trauma
Impacted disc
space, some
bone fragments
have been
extruded
anteriorly,
associated
fracture of
pedicle may be
seen.
>> Eosinophilic
granuloma
Complete
collapse of one
or more bodies.
Vertebral body is
flattened
‘vertebra plana’

28. Pedicle abnormalities
• Destruction or
sclerosis of one or
more pedicles is a
sign of spinal
metastases
Destruction of the pedicles due to
metastatic renal cell carcinoma
(a) Both pedicles of L1 and right
pedicle of T12 have been destroyed
(b) MRI showing extensive tumor
in the vertebral body and
posterior mass of tumor
compressing the dural sac.

29. Dense vertebrae
Sclerosis
• Metastases
• Lymphoma
• Paget’s disease
• Hemangioma
• Healing fracture Metastases from
breast carcinoma
Paget’s disease
Increase density and
coarse trabeculae.
Vertebral bodies is wider
than the normal ones.
Hemangioma
Vertical striation in
normal-sized vertebra.

30. SPINAL ABNORMALITIES
Applied Cross-sectional Anatomy of Spinal Cord

31. Spinal Trauma
• Plain films are the commonest initial investigation
• Should be look for…
– Alignment of the vertebral bodies and facet joints
– Fractures of the vertebral bodies, pedicles, laminae
and spinous processes
– Indirect signs of fracture such as prevertebral soft
tissue swelling
• CT is indicated as the primary imaging for patients
with high risk of spinal injury, unexplained soft
tissue swelling or if fracture is seen on the
radiographs
• MRI is indicated in any patient where a potential
spinal cord injury is suspected clinically or there
are progressive neurological defects such as due
to a cord contusion

32. Spinal Trauma
Assess the alignments
• Line runs along anterior border of vertebral
bodies
– corresponds to the anterior longitudinal
ligament
• Line runs along posterior border of vertebral
bodies
– corresponds to the posterior longitudinal
ligament
• Line runs along junction of the laminae and
spinous processes
– corresponds to the ligamentum flavum

33. Stepping in alignment at C5/C6 level.
Soft tissue swelling is seen anteriorly.
Facet dislocation with
overlap of the facet
T2-weighted MRI showing injury
to intervertebral disc and
displacement at the C6 level
causing some spinal cord
compression and edema

34. Atlantoaxial subluxation (a) Plain film taken with the neck flex and (b) T1-weighted
MRI showing widening of the space between dens of C2 and anterior aspect of C1

35. Spinal trauma
Mechanism of injury
• Hyperflexion
–Anterior structures are in
compression and posterior
elements are distracted
Sagittal CT scan showing a hyperflexion teardrop
fracture of C6. The anterior column was in compression
causing the fracture and the posterior part of the
vertebral body is retropulsed into the canal with
potential cord injury

36. Spinal trauma
Mechanism of injury
• Hyperextension
–Teardrop-shaped fragments of bone arising from the
anterior vertebral body due to avulsion by anterior
longitudinal ligament but is not usually associated with
cord injuries

37. (a) Radiograph showing an extension teardrop fracture of C2 with minimal
associated prevertebral swelling (hematoma)
(b) Hangman’s fracture: axial CT showing bilateral pars interarticularis fracture

38. Spinal trauma
Mechanism of injury
• Axial force
–Fracture of lateral masses of C1 “Jefferson’s fracture”

39. Spinal trauma
Mechanism of injury
• Axial force
–Burst fracture with fragments extending radially

40. Burst fracture of L1 caused by falling 6 m from a ladder observing (a) compression fracture of
body of L1 from radiograph, (b, c) CT showing fragments displaced into spinal cord. All three
columns are fractured. (d) T2-weighted MRI showing posterior fragments causing cord compression

41. Degenerative spinal diseases (Spondylosis)
• Nucleus pulposus is non-compressible, composed almost
completely water at birth therefore T2-hypersignal on MRI
• With ageing, the water content is reduced and T2 high
signal diminish
• This process is accelerated with degenerative disease,
associated with reduced disc height and secondary bone
changes of osteoarthritis: osteophytes.
• The annulus loses its configuration of fiber and develop
fissure
• Facet joint arthropathy

42. Cervical spondylosis
(a) Axial T2-weighted MRI showing
combination of disc protrusion and
osteophytes causing narrowing of right exiting
foramen
(b) Sagittal oblique T2-weighted MRI with a
disc protrusion causing narrowing of C6/C7
foramen

43. Disc herniation
• Degenerative annulus fissure
• In younger people, may also occur post-traumatically
• Most occur posterolaterally
– Strong posterior longitudinal ligament
– Narrows the lateral recess containing traversing nerve roots
• Less commonly: lateral disc herniation
• Loss of visualization of the fat surrounding nerve roots and
nerve sheaths

45. L4
L5
(a) Sagittal T2-weighted MRI showing a large
posterior herniation of the L4/L5 disc.
(b) Axial T1-weighted MRI of an L5/S1 disc
showing a disc herniation compressing the
adjacent nerve root.

46. Spinal cord compression
Extradural Intradural
extramedullary
Intradural
intramedullary

47. Spinal cord compression
• Extradural lesions
–Thecal sac and spinal cord are
compressed and displaced away
–Myeloma, lymphoma, metastases
–Infection, degenerative disc
protrusion

48. Spinal cord compression
a) T2-weighted MRI showing
metastases from a breast carcinoma
in the body and pedicle of T3
b) Axial T1-weighted showing a
breast cancer metastasis arising from
the right pedicle and causing
compression of spinal cord

49. Spinal cord compression
• Intradural extramedullary lesions
– Within dural sac but not within
spinal cord
– Tumor is contained within
undisplaced thecal sac but
compresses and displaces spinal
cord
– Meningioma, nerve sheath tumors:
neurofibromas or schwannomas

50. Intradural neurofibroma
T2-weighted MRI scan showing the
tumor at T6/T7 level compression
and displaced spinal cord anteriorly

51. Spinal cord compression
• Intradural intramedullary lesion
–Within the spinal cord
–Spinal cord is expanded but
undisplaced with little or no
visualization of CSF in the
thecal sac around spinal cord
–Primary spinal cord tumor:
ependymoma, astrocytoma or
metastases

52. a) Sagittal T2-weighted MRI showing an ovoid
mass (ependymoma) at the level of the conus.
b) Axial T2-weighted MRI scan below the level
of the conus showing the mass within the
intradural space surrounded by the cauda
equina

53. Metastatic tumor
• Common primary tumor:
breast, prostate, uterus,
lung, myeloma, lymphoma
• Common at T spine
• Pain, weakness, ANS
dysfunction, sensory loss
Sagittal T1-weighted scan showing focal areas
of low signal within multiple vertebral bodies
due to metastatic breast cancer

54. Spondylolisthesis
• Forward slip of one vertebral body on another
• Occur most frequently at L5/S1
• Result of stress fracture of pars interarticularis or
congenital
• Spondylolysis = defect in the pars interarticularis
without a forward slip of one vertebral body
• Stress fracture of the pars interarticularis are particular
problem in people performing active sports.

55. Spondylolisthesis
(a) Lateral view. There is forward slip
of L5 upon S1. The defect in the pars
interarticularis is seen.
(b) CT scan showing a defect in the
pars interarticularis.

56. Infection
Spondylitis and Discitis
• Pyogenic infection
– Usually via hematogenous route
– Staphylococcus aureus is most common
– Destruction of the intervertebral disc and adjacent vertebral body.
– Early, there is narrowing of the disc space with erosion of the adjoining
endplate.
– Later, bone destruction may lead to collapsed of the vertebral body and
sclerosis
– Age group 60-70 years presenting with non-specific symptom
• May involve adjacent soft tissues such as paravertebral abscess
– spread into psoas muscle
– spread inside the neural canal and compress the cord and nerve roots.

57. Plain film of discitis at C6/C7
with loss of intervertebral height
and loss of normally corticated
adjacent endplate
Sagittal T2-weighted MRI with
high signal pus in the L3/L4 disc
space
Sagittal T1-weighted MRI post
contrast, with intense
enhancement of the adjacent
vertebral bodies and between
the spinous processes

58. Infection
• Tuberculous infection
–Common age 4-50 years
–More insidious as it lacks proteolytic enzyme
–Begins anteroinferior vertebral body
–Allow preservation of the disc space
–Present with complications such as bone collapsing
resulting in focal kyphosis
–Accompanied by paraspinal abscess

59. Tuberculosis of spine
(a) Plain film showing destruction of the vertebral bodies and disc with the formation of a sharp
angulation.
(b) T2-weighted MRI showing destruction of intervertebral disc and part of the vertebral body below it. A
large inflammatory mass protrudes into spinal canal causing cauda equina compression.

60. Infection
Epidural abscess
• Secondary to extension of adjacent discitis or
ostomyelitis
• Staphylococcus aureus is most common
• Common in middle age men
• MRI shows enhancement of extradural collection
• Common in lumbar and thoracic region

61. Sagittal (a) and axial (b) T1-weighted MRI with
contrast shows well-defined epidural abscess
with enhancing margin

62. Intrinsic disorders of the spinal cord
Syringomyelia
• A condition where a CSF-contained cavity forms within
the middle of the cord.
• In the cervical region, a syringomyelic cavity is often
associated with a Chiari I malformation (cerebellar
tonsil lie below the foramen magnum), which lead to
presentation with upper limb sensory disturbance and
lower limb weakness

63. T2-weighted image showing syrinx with
Chiari I malformation
The tips of the cerebellar tonsils extend
through the foramen magnum to reach the
level of C2

64. Congenital Abnormalities
Spina bifida
• In utero incomplete closure of embryological neural tube
• Spina bifida occulta: failure of fusion of posterior bony
neural arch but intact soft tissue and skin
• Meningocele: protrusion of membrane
• Meningomyelocele: protrusion of neural element
• Laminae of several vertebrae will be absent and distance
between pedicles wille be increased.

65. Spina bifida with lipomyelomeningocele
Sagittal (a) and Axial (b) T2-weighted MRI shows open defect in posterior part of lumbosacral vertebrae
with a CSF-filled sac containing nerve roots protrusion from the spinal canal via a spina bifida.
Syringomyelia is also noted at thoracolumbar region.

66. References
• Rockall A, et al,
Diagnostic Imaging, 7th Edition
Wiley-Blackwell. 2013
• Tank PW,
Atlas of Anatomy
Lippincott Williams & Wilkins. 2008
• Castillo M,
Neuroradiology Companion
Lippincott Williams & Wilkins. 2012
• www.radiopaedia.org