1. Presenter : Dr. Charusmita Chaudhary
Moderator: Dr R. K. Gogoi

2.  In the spine, the most common congenital lesions
presenting to medical attention are the
 diverse forms of spinal dysraphism
 diverse forms of caudal spinal anomalies
:diagnosed::::
 Prenatally
 at birth
 in early childhood
 in adulthood

3. Techniques of imaging
 Radiography
 Computed Tomography
 Magnetic Resonance Imaging
 Ultrasonography
 Nuclear Imaging

4. Etiology
Multifactorial
genetic,
environmental influences,
folic acid deficiency in the mothers.
Ultrasonography is performed in high-risk
pregnancies.

5. Categories
Spina bifida aperta
(myelocele and
myelomeningocele)
Occult spinal
dysraphism
Caudal spinal anomalies

6. Spinal Cord Development
 can be summarized in three basic embryologic stages
1. The first stage : Gastrulation (the 2 or 3 week)
conversion of the embryonic disk from a bilaminar disk to a trilaminar
disk.
1. The second stage : primary neurulation (weeks 3–4) the notochord and
overlying ectoderm interact to form the neural plate. The neural plate
bends and folds to form the neural tube, which then closes bidirectional in
a zipperlike manner
2. The final stage : secondary neurulation (weeks 5–6), a secondary neural
tube is formed by the caudal cell mass. The secondary neural tube is
initially solid and subsequently cavitation, eventually forming the tip of
the conus medullaris and filum terminale by a process called retrogressive
differentiation.
Abnormalities at steps can lead to spine or spinal cord malformations
the cephalic and caudal portions of the spinal cord form by distinctly
different mechanisms, they exhibit distinctly different types of
malformation

7. Gastrulation. a Dorsal view and b
transverse view of the
bilaminar embryonic disk. First
ingressing cells at Hensen’s node
move anterior to form head
processes and notochord. Cells
ingressing
through primitive streak migrate
ventrally and laterally to form
mesodermal a and endodermal
precursors

8. NEURULATION AND DERANGEMENTS OF NEURULATION
 four stages of neurulation
Formation
Shaping of Bending of
of the
the Neural the Neural Fusion
Neural
Plate Plate
Plate

9. Primary neurulation.
Formation of the Neural Plate
Shaping of the Neural Plate
Bending of the Neural Plate
Fusion
Illustrations of primary neurulation.
Notochord (circle) interacts with overlying
ectoderm to form neural plate (dark green),
which then bends to form neural tube that
ultimately closes in zipperlike fashion

10. Canalization and retrogressive
differentiation (synonym: secondary
neurulation). Diagrammatic representation
of proposed embryogenesis.

11. VASCULAR ANATOMY

12. Categorization of Spinal Dysraphisms
 Spinal dysraphisms
open and closed types
 In an open spinal dysraphism
there is a defect in the overlying skin, and the neural
tissue is exposed to the environment.
In a closed spinal dysraphism, the neural tissue is
covered by skin.
Closed spinal dysraphisms can be further subcategorized
on the basis of the presence or absence of a
subcutaneous mass.

13. Classification of spinal dysraphisms

14.  Open spinal dysraphism (OSD; characterized by
exposure of nervous tissue through a congenital Defect
 Almost 99% are myelomeningoceles
 Variable degree of sensorimotor deficits,bowel and
bladder dysfunction
 All patients with OSD have Chiari II
 Role of MRI: anatomic characterization;presurgical
evaluation; identification of cord splitting when
present

15. Deranged Neurulation
 Spina Bifida Aperta: Myelocele and
Myelomeningocele
 spina bifida aperta designates those forms of spinal
dysraphism in which the neural tissue and/or meninges
are exposed to the environment because the skin,
fascia, muscle, and bone are deficient in the midline of
the back

16. Open Spinal Dysraphisms
Myelomeningocele and Hemimyelomeningocele and
myelocele hemimyelocele
 Myelomeningoceles and
myeloceles are caused by defective
closure of the primary neural tube
 Hemimyelomeningoceles and
hemimyeloceles can also
 Exposure of the neural placode
through a midline skin defect on
occur but are extremely rare .
the back. These conditions occur when
 Myelomeningoceles account for
a myelomeningocele or
more than 98% of open spinal myelocele is associated with
dysraphisms diastematomyelia (cord
 Myeloceles are rare. splitting) and one hemicord
fails to neurulate.

17.  Open spinal dysraphisms are often diagnosed
clinically, so imaging is not always performed.
 When imaging is performed,
The main differentiating feature between a
myelomeningocele and myelocele is the position of
the neural placode relative to the skin surface
 The neural placode protrudes above the skin surface
with a myelomeningocele and is flush with the skin
surface with a myelocele

18. Myelomeningocele. Axial schematic of Myelomeningocele. Axial T2-
myelomeningocele shows neural weighted MR image Myelomeningocele. Sagittal T2-
placode (star) protruding above skin weighted MR image).
surface due to expansion of underlying
subarachnoid space (arrow).

19. Myelocele. Axial T2-weighted MR
Myelocele. Axial schematic of myelocele image in 1-day-old girl shows exposed
shows neural placode (arrow) flush with neural placode (arrow) that is flush
skin surface. with skin surface, consistent with
myelocele. There is no expansion of
underlying subarachnoid space

20. Antenatal ultrasonogram shows a lumbar meningocele.

22. Chiari Malformations

23. Chiari Malformations
 share common features,
 variable degree of reduction in size of the posterior
fossa and (with the exception of the type IV)
herniation of portions of the cerebellum into the
foramen magnum, it is accepted that type I (resulting
from a mesodermal hindbrain abnormality) should be
separated from the other types that are related to
neural tube closure defects

24. Chiari-I malformation
 Cerebellar tonsils >5 mm below basion-opisthion
line or 3–5 mm and neurological signs
 or peg-like tonsils or syrinx
 14–56% neurologically normal
 Significant incidence of hydrosyringomyelia
 and/or hydrocephalus
 Caudal ectopia of the cerebellar tonsils into the
foramen magnum is the hallmark of the Chiari-I
malformation

25. Axial T1-weighed image shows crowding of the
foramen magnum due to the presence ofthe
Sagittal T1-weighted image shows caudal tonsils (T) behind the medulla oblongata
tonsillar ectopia (arrow).
The posterior fossa is small
Multiple haustrations are a typical fi nding with Chiari-I-
associated hydromelia
Sagittal T1-weighted image

27. Chiari-II malformation
 Small posterior fossa
 Downward displacement of vermis, brainstem and
fourth ventricle
 90% has OSD
 Associated brain malformations
Antenatal ultrasonogram shows a lemon sign and a banana
sign

28. Chiari II malformation with hydromyelia

29. Sagittal images very small posterior cranial
fossa and the typical cascade of herniations
constitutin the hallmark of the Chiari-II
malformation.

30. Diagrammatic representation of the spectrum of cervicomedullary deformities
in the Chiari II malformation

31.  Chiari II malformation as result of diversion of ventricular CSF to the
amnion with “collapse” of the developing ventricular system
The fluid-filled space of the developing brain and spinal cord is
called the neurocele.
 The medial walls of the thoracic neural tube normally appose and
occlude the neurocele transiently during central nervous system
 distal myelomeningocele fail to occlude the neurocele, even at sites
remote from the myelomeningocele.
 This failure to appose the walls appears to result from the same
biosynthetic defect in cell surface glycosaminoglycans that prevents
the neural tube from closing.
 the mechanism that causes failure of neurulation also causes failure
of apposition of the medial walls of the neurocele.

32. theory proceeds as follows
 neurocele is not occluded, CSF passes freely down the central canal and out
the myelomeningocele to the amnionic cavity
 This abnormal shunt collapses the developing primitive ventricular system.
Therefore, the volume of the ventricular system and surrounding neural tissue
is less than normal.
The mesenchyme condenses in relation to an abnormally small volume of
developing CNS.
This establishes a smaller-than normal posterior fossa with low tentorium.
 The developing CNS must then grow within an envelope of membrane,
cartilage, and bone that is too small for it.
 This leads to failure to form the pontine flexure, downward growth of the
cervicomedullary junction, medulla, and cerebellum through the foramen
magnum, and upward growth of the cerebellum through the incisura.

33.  11. Reduced size of the third ventricle means closer approximation of the
thalami with larger massa intermedia.
 Collapse of the cerebral ventricles leads to disorganization of the developing
hemispheres with gray matter heterotopias,disorganization of cerebral gyri, and
dysgenesis of the corpus callosum
The collapse of the ventricular system leads to disordered development of the
membranous bone of the vault .Normally, the skull develops from centers in
each cranial plate. As the brain expands, the collagen bundles are drawn out
from those centers in an orderly radial fashion, much like the uniform
expansion of the surface of an inflating balloon. As radial expansion proceeds,
the collagen bundles become calcifiable and membranous bone forms.
Lack of distension of the brain mass by increasing volumes of CSF produces
disordered arrays of collagen bundles. Thus, instead of radial lines of collagen,
whorls and coils of collagen form with varying density between them.
Ossification of this disorganized collagen mat then leads to lükenshädel

34. Chiari malformation
Chiari-III malformation Chiari-IV malformation
Chiari II + cephalocele Severe cerebellar hypoplasia
+ myelomeningocele

35. Closed Spinal Dysraphisms

36. Closed Spinal Dysraphisms With a
Subcutaneous Mass
Lipomas with a dural defect Meningocele
 Lipomas with a dural defect include both  Herniation of a CSF-filled sac lined by
lipomyeloceles and lipomyelomeningoceles. dura and arachnoid mater is referred
to as a meningocele. The spinal cord is
 These abnormalities result from a defect in
not located within a meningocele but
primary neurulation whereby mesenchymal may be tethered to the neck of the
tissue enters the neural tube and forms CSF-filled sac.
lipomatous tissue  2 types…
 characterized clinically by the presence of a  Posterior meningoceles herniate
subcutaneous fatty mass above the through a posterior spina bifida
intergluteal crease. (osseous defect of posterior spinal
 The main differentiating feature between a elements) and are usually lumbar or
lipomyelocele and lipomyelomeningocele is sacral in location but also can occur in
the position of the placode–lipoma interface the occipital and cervical regions
 With a lipomyelocele, the placode–lipoma
 Anterior meningoceles are usually
presacral in location but also can
interface lies within the spinal canal occur elsewhere
 With a lipomyelomeningocele, the placode–
lipoma interface lies outside of the spinal
canal due to expansion of the subarachnoid
space

37. Lipomyelocele. Axial T2-weighted MR
image shows placode–lipoma interface Lipomyelocele. Sagittal T1-
Lipomyelocele. Axial schematic of weighted MR image
(arrow) within spinal canal,
lipomyelocele shows placode– characteristic for lipomyelocele lipomyelocele shows
lipoma interface (arrow) lies subcutaneous fatty mass
within spinal canal (black arrow) and placode–
lipoma interface (white
arrow) within spinal canal.

39. the hairy tuft overlying
subcutaneous lipomas

40. Lipomyelomeningocele. Axial
schematic of
lipomyelomeningocele shows
placode–lipoma interface
(arrow) lies outside of spinal
canal due to expansion of
subarachnoid space
Lipomyelomeningocele. Axial T1-weighted MR image in
18-month-old boy shows lipomyelomeningocele (arrow)
that is differentiated from lipomyelocele by location of
placode–lipoma interface outside of spinal canal due to
expansion of subarachnoid space.

41. ,.
B,.
C.
, Sagittal T2-weighted
Sagittal T1-weighted MR Sagittal T2-weighted MR
MR image in 30-
image shows posterior image shows large
month-old girl shows
herniation of CSF-filled sac posterior meningocele
small posterior
(arrow) in occipital region, (arrow) in cervical region
meningocele (arrow) in
consistent with posterior
lumbar region
meningocele
6—Posterior meningocele
Sagittal (A) and axial (B) T2-weighted MR
images in 6-month-old boy show small anterior
meningocele (arrows

42.  Terminal myelocystocele  Myelocystocele—
 Herniation of large terminal  A nonterminal
syrinx (syringocele) into a myelocystocele occurs
posterior meningocele through a
posterior spinal defect is when a dilated central
referred to as a terminal . canal herniates through a
 The terminal syrinx component posterior spina bifida
communicates with the central defect Myelocystoceles are
canal, and the meningocele
component communicates with covered with skin and can
the subarachnoid space. occur anywhere but are
 The terminal syrinx and most commonly seen in
meningocele components do not
usually communicate with each the cervical or
other cervicothoracic regions

43. Schematic
Terminal myelocystocele. of nonterminal
A, Sagittal schematic of terminal myelocystocele shows terminal myelocystocele shows
syrinx (star) herniating into large posterior meningocele herniation of dilated
(arrows). central canal through
B and C, Sagittal (B) and axial (C) T2-weighted MR images show posterior spinal defect
terminal syrinx (white arrows) protruding through large
posterior spina bifida defect and herniating into posterior
meningocele component (black arrows).

44. Closed Spinal Dysraphisms
Without a Subcutaneous Mass
Simple dysraphic states Complex dysraphic states
 Complex dysraphic states be
 intradural lipoma, divided into two categories:
 filar lipoma,  A) disorders of midline
 tight filum terminale, notochordal integration,
persistent terminal ventricle dorsal enteric fistula,
neurenteric cyst, and
 dermal sinus.
diastematomyelia,
 B)disorders of notochordal
formation,
 caudal agenesis and
segmental spinal dysgenesis.

45. lipoma
 An intradural lipoma refers to a lipoma located along the dorsal midline
that is contained within the dural sac
 No open spinal dysraphism is present
 commonly lumbosacral in location
 usually present with tethered-cord syndrome
 Fibrolipomatous thickening of the filum terminale is referred to as a
filar lipoma.
 On imaging, a filar lipoma appears as a hyperintense strip of signal on
T1-weighted MR images within a thickened filum terminale
 Filar lipomas can be considered a normal variant if there is no clinical
evidence of tethered-cord syndrome
tethered-cord syndrome a clinical syndrome of
progressive neurologic abnormalities in the setting of
traction on a low-lying conus medullaris

46. Spinal lipoma
focal premature disjunction of epidermal
from neural ectoderm.
curved arrows are also used to
indicate the course of mesenchyme
migrating through the focal disjunction to
the dorsal surface of the closing neural folds

47. Diagrammatic representations of spinal lipomas. A: Intradural lipoma. The laminae
(L) are bifid. The dura (dark line) is intact. The pia-arachnoid (dashed line) encloses
the spinal cord and the lipoma. The lipoma lies predominantly within a midline cleft in
the dorsal spinal cord but fungates beneath the pia to bulge into the dorsal
subarachnoid space
D, dorsal root; V, ventral root; G, dorsal root ganglion. B: Lipomyelocele. There is
posterior spina bifida with everted C: lipomyelomeningocele

48. Intradural lipoma Filar lipoma
, Sagittal (A) and axial (B) T1-weighted MR
images I with filar lipoma (arrows),
which has characteristic T1 hyperintensity and
marked thickening of filum terminale
.
Sagittal T1-weighted (A) and sagittal T2-
weighted fat-saturated (B) MR images show large
intradural lipoma (arrows), which is
hyperintense on T1-weighted image and hypointense
on T2-weighted fat-saturated image. Lipoma is
attached to conus medullaris, which is low lying.

50. Intraspinal lipomas may produce
posterior scalloping of vertebral
bodies and flattening of the
pedicles
D/D intraspinal tumors;
neurofibromatosis; acromegaly;
achondroplasia; communicating
Plain radiographs show posterior scalloping. hydrocephalus; syringomyelia;
and a number of congenital
syndromes, including Ehlers-
Danlos, Marfan, Hurler,
Morquio, and osteogenesis
imperfecta syndromes.

51. Simple dysraphic states
 TIGHT FILUM TERMINALE
Tight filum terminale is
characterized by hypertrophy and
shortening of the filum terminale .
 This condition causes tethering of
the spinal cord and impaired
ascent of the conus medullaris.
 The conus medullaris is low lying
relative to its normal position,
which is usually above the L2–L3
disk level
fila thicker than 2 mm
were abnormal.
Sagittal T2-weighted MR image in 12-month-old boy shows tight filum terminale, characterized by
thickening and shortening of filum terminale (black arrow) with low-lying conus medullaris.
Incidental cross-fused renal ectopia (white arrow) is also present.

52. Left, plain radiograph of the lumbar spine
Left, anteroposterior (AP) plain
radiograph of the lumbar spine shows shows bony defects in the laminae of L2 to
a defect within the laminae of S1 and S1. Right, myelogram shows a split cord.
Left plain anteroposterior (AP) radiograph of S2. Right, myelograms in the same
the lumbar spine shows spina bifida occulta. patient show a markedly thickened,
Right, myelogram of the same patient shows a low tethered cord
thick tethered cord

53. Simple dysraphic states
 TERMINAL VENTRICLE
 Persistence of a small, ependymal
lined cavity within the conus
medullaris is referred to as a
persistent terminal ventricle .
 It appears to represent the point of union
between the portion of the central canal
made by neurulation and the portion made
by canalization of the caudal cell mass
 Key imaging features include
location immediately above the
filum terminale and lack of contrast
enhancement, which differentiate
this entity from other cystic lesions Persistent terminal ventricle.
of theconus medullaris A and B, Sagittal T2-weighted (A) and sagittal
T1-weighted contrast-enhanced (B) MR images in
12-month-old boy show persistent terminal ventricle
as cystic structure (arrows) at inferior aspect of
conus medullaris, which does not enhanc

54. Simple dysraphic states
 Dermal sinus
 A dermal sinus is an epithelial lined
fistula that connects neural tissue
or meninges to the skin surface.
 If the superficial ectoderm fails to
separate from the neural ectoderm
at one point,
 lumbosacral region and is often
associated with a spinal dermoid at
the level of the cauda equina or
conus medullaris
 Clinically, patients present with a
midline dimple and may also have
an associated hairy nevus,
hyperpigmented patch, or capillary
hemangioma
 Surgical repair is of great importance because , Sagittal schematic (A) and sagittal T2-weighted MR image (B) in
the fistulous connection between neural tissue
and the skin surface can result in infectious 9-year-old girl show intradural dermoid (stars) with tract
complications such as meningitis and abscess extending from central canal to skin
surface (black arrows). Note tenting of dural sac at origin of dermal
sinus (white arrows).
C, Axial T2-weighted MR image from same patient as in B shows
posterior location of hyperintense dermoid (arrow)

55. .
Proposed embryogenesis of dorsal dermal
sinus by incomplete disjunction
Dorsal dermal sinus. Diagrammatic
representation

56. Complex dysraphic states
DISORDERS OF MIDLINE
DISORDERS OF
NOTOCHORDAL NOTOCHORDAL FORMATION
INTEGRATION
 dorsal enteric fistula,  caudal agenesis
 neurenteric cyst  segmental spinal dysgenesis.
 diastematomyelia,

57. Disorders of midline notochordal
integration
 Dorsal enteric fistula and neurenteric cyst
A dorsal enteric fistula occurs when there is an abnormal
connection between the skin surface and bowel.
Persistence of a patent neurenteric canal (canal of
Kovalevsky
Neurenteric cysts represent a more localized form of dorsal
enteric fistula .
These cysts are lined with mucin-secreting epithelium
similar to the gastrointestinal tract and are typically
located in the cervicothoracic spine anterior to the spinal
cord

58. Split notochord syndrome. Diagrammatic
representation of developmental posterior
enteric remnants.

59. 5—Neurenteric cyst in 3-year-old girl
A and B, Sagittal T2-weighted (A) and axial T1-weighted (B)
MR images show bilobed neurenteric cyst (arrows) extending
from central canal into posterior mediastinum.
C, Three-dimensional CT reconstruction image shows osseous
opening (arrow) through which neurenteric cyst passes. This
opening is called the Kovalevsky canal

60. Disorders of midline notochordal
integration
 Diastematomyelia
Separation of the spinal cord into two hemicords is referred to as
diastematomyelia.
 The two hemicords are usually symmetric, although the length of
separation is variable.
 There are two types of diastematomyelia.
 In type 1Dual Dural-Arachnoid Tubes (Pang Type I), the two
hemicords are located within individual dural tubes separated by an
osseous or cartilaginous septum
 In type 2, Single Dural-Arachnoid Tube (Pang Type II) there is a
single dural tube containing two hemicords, sometimes with an
intervening fibrous septum
 Diastematomyelia can present clinically with scoliosis and tethered-cord
syndrome. A hairy tuft on the patient's back can be a distinctive finding
on physical examination

61. Embryogenesis of split notochord syndrome
Posterior view of the patient reveals the large patch of
long, silky hairs
overlying stematomyelia and a small sacral dimple (arrow

62. Type 1 diastematomyelia
Sagittal T2-weighted MR (A), axial T2-weighted MR (B), and axial
CT with bone algorithm (C) images in 6-year-old boy show two
dural tubes separated by osseous bridge (arrows), which is
characteristic for type 1 diastematomyelia.
Axial CT scans through the
upper lumbar spine show a
split cord
lumbosacral region; a long, tethered cord; and
diastematomyelia.

63. Type 2 diastematomyelia.
, Sagittal T1-weighted (A), coronal T1-
weighted (B), and axial T2-weighted (C)
MR images show splitting of distal cord
into two hemicords (white arrows, B
and C) within single dural tube, which
is characteristic for type 2
diastematomyelia. Incidental filum
lipoma (black arrows, A and B) is
present as well.

64. Disorders of notochordal
formation:
 Caudal agenesis
 Caudal agenesis refers to total or partial agenesis of the
spinal column and may be associated with the
following: anal imperforation, genital anomalies, renal
dysplasia or aplasia, pulmonary hypoplasia, or limb
abnormalities.

65. Caudal agenesis
Caudal agenesis can be categorized
into two types.
In type 1, there is a high position
and abrupt termination of the
conus medullaris.
In type 2, there is a low position
and tethering of the conus
medullaris
, Sagittal T2-weighted (A) and sagittal T1-
weighted (B) MR images in show agenesis of sacrum. Conus
medullaris is high in position and wedge shaped (arrow) due to
abrupt termination. These findings are characteristic of type
1 caudal agenesis. Distal cord syrinx (arrowhead) is
present as well.

66. Syndrome of Caudal Regression

67. Syndrome of Caudal Regression
 constellation of anomalies of the hind end of the trunk,
including partial agenesis of the thoracolumbosacral spine,
imperforate anus, malformed genitalia, bilateral renal
dysplasia or aplasia, pulmonary hypoplasia, and, in the
most severe deformities, extreme external rotation and
fusion of the lower extremities (sirenomelia)
 Sacral agenesis arises early in gestation, probably before the
10th week of gestation
 diabetes mellitus,
 OEIS complex, VATER syndrome (see later discussion), and
 congenital heart defects (24%); genitourinary complaints
with hydronephrosis, unilateral renal agenesis, pelvic and
horseshoe

68. Posterior view of the patient reveals the
short, shallow intergluteal cleftand poorly
developed gluteal musculature.

69. Classification of Lumbosacral
Agenesis
 I Total SA; some lumbar vertebrae also missing
IWa Ilia articulate with sides of the lowest vertebra,
maintaining relatively normal transverse pelvic diameter
INa Ilia articulate or fused with each other below last
vertebra, severely shortening transverse pelvic diameter
 II Total SA; lumbar vertebrae not involved
IWa Ilia articulate with sides of L-5 vertebra maintaining
relatively normal transverse pelvic diameter
INa Ilia articulate or fuse with each other below L-5
vertebra, severely shortening transverse pelvic diameter
 III Subtotal SA; at least S-1 is present, sacrum lacks four, three, two, or
one of its caudal segments, ilia articulate with sides of rudimentary
sacrum, maintaining normal transverse pelvic diameter

70.  IV Hemisacrum
IVA Total hemisacrum; all sacral segments present
on one side, but entire opposite side is missing
IVB Subtotal hemisacrum, unilateral; all sacral
segments present on one side, only part of opposite side is
missing
IVC Subtotal hemisacrum, bilateral; part of each side
is missing but to different extents
 V Coccygeal agenesis
VA Total
VB Subtotal

71. Disorders of notochordal formation
 Segmental spinal
dysgenesis
 The clinical–radiologic
definition of segmental
spinal dysgenesis includes
several entities: segmental
agenesis or dysgenesis of
the thoracic or lumbar
spine, segmental
abnormality of the spinal
cord or nerve roots,
congenital paraparesis or
paraplegia, and congenital
lower limb deformities. Three-dimensional CT reconstruction image (A) in
 Three-dimensional CT 4-year-old girl and schematic illustration (B) show
multiple
reconstructions can be segmentation anomalies in lumbar spine (superior to
helpful in showing various inferior
beginning at level of arrow): partial sagittal partition,
vertebral segmentation butterfly vertebra, hemivertebra, tripedicular vertebra,
anomalies and
widely separated butterfly vertebra

72. Congenital Spine and Spinal Cord Malformations—Pictorial Review

74. CONTENTS..
STAGES OF DEVELOPMENT
OF VC
formation of mesenchymal vc
formation of cartilaginous vc
ossification of vc

75. development
begins during
gastrulation when
epiblastic cells migrate
toward the cranial
portion of the primitive
streak, ingress through
the primitive groove, and
then migrate laterally as
the prospective somitic
mesoderm

76. stages
 Stage 1
formation of mesenchymal vertebral
column
: 4th week
1.Migration of sclerotomes
. Differentiation of
sclerotomic segments
Each segments
differentiated into
Cephalic part (less
condensed)
Caudal part (more
condensed)

77. 3. Development of intervertebral
discs
 Densely packed cell
move cranially to the
middle part of each
segments
 Form peripheral part
annulus fibrosus
 Enclosed notochord
expands and undergo
mucoid degeneration
 Form central part –
nucleus pulposus

79. 4. Development of the body of
vertebrae
 Caudal remained part fuse
with cephalic part
adjacent to it to form
mesenchymal centrum
 Notochord degenerates
and disappears when
surrounded by vertebral
body

80. 5. Development of neural arch
 Sclerotomic tissue migrate
backward from both side of
centrum and surround
neural tube.
 Neural spine forms at
meeting point of neural
arch
 Sclerotomic tissue also
extends laterally from both
sides of centrum form 2
processes
 Costal (ventral)
 Transverse (dorsal)

81. Stage 2
Stage of formation of cartilaginous vertebral column
 6th week
 2 centers of chondrification in each Centrum
appear
 Fuse together at the end of embryonic period
(8th week) form cartilaginous centrum
– Centers of chondrification appear in neural
arhes and fuse with each other and centrum
– Chondrification spreads until a cartilaginous
vertebral column formed

82. Stages of ossification
 Comprises of 2 stages:
 1. primary ossification center
 2. secondary ossification center
 Primary ossification center at the end of 8th week.
 3 ossification centers are present by the end of
embryonic period
 one in the centrum
 one in the neural arch

83. Process:
 bony halves of the vertebral arch fuse together during
the first 3 to 5 years
 the arches articulate with the centrum at cartilaginous
neurocentral joints
 these joints dissapear when vertebral arches fuses with
the centrum during the 3rd to 6th years

84. Secondary ossification center
 Time of development: after puberty
the 5 secondary ossification center appears at,
 1. tip of spinous process
 2. tip of each transverse process
 3. superior rim of the vertebral body
 4. inferior rim of the vertebral body

86. Fate of notochord
 Cranial part: merged with basilar part of occipital bone
& posterior part of body of sphenoid
 Notochord located in the vertebra undergo
degeneration and disappear
 The ones located in between undergo mucoid
degeneration to form nucleus pulposus

87. Fate of the costal process
 Costal process results from ventrolateral outgrowth of
the caudal, denser half of a sclerotome.
 In the cervical region: form anterior and lateral
boundary of the foramen transversum
 In the thoracic region: form the ribs
 In the lumbar region: fuse with the transverse process
 In the upper sacral region: they unite to form the
anterior portion of the ala of sacrum

89. Spina bifida
Cause: incomplete fusion of
halves of the vertebral arches
resulting in midline defect
usually in lumbosacral
region
Feature: It varies, but
generally the small bones
(vertebrae) that make up the
spine don’t form fully and
may have gaps between
them.

90. Congenital Spinal Deformity
 caused by anomalous vertebral development in the
embryo
 simple and benign, causing no spinal deformity, or they
may be complex, producing severe spinal deformity or
even cor pulmonale or paraplegia.

91. patterns
 Hyperlordosis
 Kyphosis
 scoliosis

92. On basic developmental pathogenesis,
divided into the following 3 categories:
 Malformation a failure of the embryologic differentiation
and/or development of a specific anatomic structure,
causing it to be absent or improperly formed before the
fetal period commences formation of a hemivertebra.
 Disruption destruction of an anatomic feature that formed
normally during the embryonic period. This phenomenon,
resulting in a structural defect, limb….
 Deformation an alteration in the shape or structure of an
individual vertebra or of the entire spine during the fetal
and/or postnatal periods, after the involved region's initial,
normal differentiation

93. Defects of formation may be
classified as follows:
 Anterior formation failure - This results in kyphosis,
which is sharply angulated.
 Posterior formation failure - This is rare but can
produce a lordotic curve.
 Lateral formation failure - This occurs frequently and
produces the classic hemivertebrae of congenital
scoliosis

94. Schematic drawing depicting the
development of
normal and abnormal vertebral bodies

95. Vertebral Body Configurations
Congenital
B. Hemivertebra
 Asomia (A genesis) Unilateral wedge vertebra is due to lack of
ossification of one-half of the body
apex of the wedge reaching the midplane
Scoliosis is often present

96. Metametric hemivertebrae in the lower
Dorsal hemivertebra involving Li
lumbar spine
with “mermaid” deformity of the lower
extremities

97. Metametric hemivertebrae in the lower
Dorsal hemivertebra involving Li
lumbar spine
with “mermaid” deformity of the lower
extremities

98. “Butterfly” vertebra involving L4
Vertebrae with coronal clefts.

99. (A) Block vertebra with congenital fusion of
C4 and
CS Note the presence of a “waist” at the site of
fusion (arrow). (B) Acquired vertebral body fusion
of CS and C6.

100. Hemivertebra
Cause: failure of one of the
chondrofication center to appear
and subsequent failure of half of
vertebra to form
Feature: defective vertebra produce
scoliosis ( lateral curvature)
Most likely to cause neurologic
problems

101. Sacralization of 5th lumbar vertebra
Cause: 5th lumbar is fused with the
sacrum
Feature: number of lumbar vertebra
is 4 and the sacrum is formed of 6
vertebra

102. Lumbrization of first piece of
sacrum to form separate vertebra
Cause: separation
of first piece of
sacrum to form
separate vertebra
Feature: number
of lumbar vertebra
is 6 and the sacrum
is only formed of 4
sacral vertebra

103. Congenital Kyphosis
 Two types of congenital kyphosis exist:
defects of segmentation
defects of formation
 Defects of segmentation occur most often in
midthoracic or thoracolumbar regions and may involve
2-8 levels
 . produce a round kyphosis

104. Congenital kyphosis

105. Congenital Scoliosis
 lateral curvature of the spine that is caused by
congenital anomalies of vertebral development
classified according to the types of anomalies.
 Failure of formation
 Partial failure of formation (wedge vertebra)
 Complete failure of formation (hemivertebra)

106.  Failure of segmentation (see image below)
Unilateral failure of segmentation
(unilateral unsegmented bar)
Bilateral failure of segmentation (block
vertebra)
Mixed (see image below)

107. Congenital scoliosis

108. Congenital Lordosis
 least common of the 3 major patterns of congenital
spinal deformity
 caused by a failure of posterior segmentation in the
presence of anterior active growth
 usually is progressive
 Treatment of congenital lordosis is purely surgical.

109.  •We can summarize above notes as follows:
 1.The vertebra is intersegmental structure made up from
portions of two somites the position of the somite is
represented by intervertebral disc.
 2.The transverse processes and the ribs are
intersegmental structures. They separate the muscles
derived from two adjoining myotomes.
 3.Spinal nerves are segmental structures. They emerge
from between two adjacent vertebrae and lie between
two adjacent ribs.
 4.The blood vessels supplying the structures derived
from the myotome are intersegmental like vertebrae.
Therefore the intercostal and lumbar arteries lie
opposite the vertebral bodies

110. Imaging of the bony spine requires methods different from those used to
image the spinal canal and its contents.
 Age influence the choice of modality
 The best way to image skeletal anomalies : plain radiography combined
with conventional tomography
 Spinal malformations :best performed by MRI
 Skeletal scintigraphy with technetium-99m diphosphonates has high
sensitivity but low specificity
 In the evaluation of the spinal canal, ultrasonography is limited to the
neonatal period, though a spinal defect covered with soft tissue may be
imaged well into adult life
 Fetal ultrasonography is increasingly used as a primary screening tool for
NTDs, usually at about 18 weeks' gestational age

111. Limitations of techniques
 X ray : Radiation
 delivers a high dose : gonads, particularly in female patients.
 Ultrasonography remains operator dependent; depends on the
skill and experience and on the quality of the equipment.
 Transaxial CT images may be difficult to interpret because of the
complex anatomy of the vertebral bodies, the presence of
segmentation anomalies, and the presence of spinal curvature
abnormalities. , in as much as sagittal and coronal
reconstruction now provide exquisite images of the spine.
 In parts of the developing world, MRI is not readily available
In addition, use of MRI may not be possible in patients with
claustrophobia, and it is contraindicated for some patients with
implanted devices
Children may require sedation.

112. Special concerns
 Neural tube defects (NTDs) exact emotional and
economic toll on families and health care systems
The tragedy is that NTDs are preventable simply by
having women take a folic acid supplement during the 2
months before they become pregnant.
0.4 mg daily before conception and for the first 3
months of pregnancy, reduces the risk of having a baby
with spina bifida. risk(4 mg) of folic acid.

113. SUMMARY
 Spinal dysraphism, or neural tube defect (NTD), is a broad term
encompassing a heterogeneous group of congenital spinal anomalies,
which result from defective closure of the neural tube early in fetal life
and anomalous development of the caudal cell mass.
 can cause progressive neurologic deterioration.
 The anatomic features common to the entire group is an anomaly in the
midline structures of the back, especially the absence of some of the
neural arches, and defects of the skin, filum terminale, nerves, and
spinal cord.
 classified as closed forms or open forms,
 open forms are often associated with hydrocephalus and Arnold-chiari
malformation type II
 Spina bifida is described in the medieval literature, although the
condition was recognized even earlier. Indeed, the association of foot
deformities with lumbar or lumbosacral hypertrichosis may be the origin
of the mythological figure of the satyr.

114.  Spina bifida occulta is characterized by variable absence of
several neural arches and various cutaneous
abnormalities,
 such as lipoma, hemangioma, cutis aplasia, dermal sinus,
or hairy patch, and it is often associated with a low-lying
conus
 Whenever the conus lies below the L2-3 interspace in an
infant, cord tethering should be considered.
 Patients with spina bifida occulta may present with
scoliosis in later years.
 Approximately 95% of couples that have a fetus affected
with ONTD have a negative family history.

115. THANK YOU
FOLIC ACID
IMAGING OF CONGENITAL ANOMALIES OF
SPINE AND SPINAL CORD