16. Stages of Neural-Spinal Development- Third Week
• Neural Plate
Moore, K. The Developing Human
17. Stages of Neural-Spinal Development-
Fourth Week
• Neural Plate
– Neuralization- closure of the neural groove to
form the neural tube
Moore, K. The Developing Human
18. Stages of Neural-Spinal Development-
Fourth Week
• Somites- 42 pairs
• Neural Plate and cranial-most 4 somites form
the brain
Moore, K. The Developing Human
19. Stages of Neural-Spinal Development-
Fourth Week
• Somites- divide into dense and sparse areas
Moore, K. The Developing Human
20. Stages of Neural-Spinal Development-
Fourth Week
• Centrum- dense portion of cephalad with
sparse portion of caudal somite
Moore, K. The Developing Human
24. Stages of Neural-Spinal Development- Fifth Week
• Neural Plate- Thinning of 4th ventricle for
Foramen of Magendie
• Notochord- Degeneration in Vertebral Body
area
Moore, K. The Developing Human
25. Stages of Neural-Spinal Development- Fifth Week
• Vertebrae- Mesenchymal model finished
Moore, K. The Developing Human
26. Stages of Neural-Spinal Development-
Sixth Week
• Vertebrae-
– Chondrification- 6th week
– Ossification Centers- 7th week
Moore, K. The Developing Human
27. Further Vertebral Development
• Neural Central Joint- fuses 3rd to 6th year
• Vertebral Arch- fuses 3rd to 5th year
Moore, K. The Developing Human
29. A Clarification of Terms
• Physeal Plate- Cartilage plate where growth occurs.
• Epiphysis- Area of bone on the end of the physeal plate that
contributes to longitudinal growth of a long bone
• Apophysis- An area of bone adjacent to a physeal plate that
does not contribute to longitudinal growth (Secondary Centers
of Ossification)
30. A Clarification of Terms
• Apophysis- An area of bone adjacent to a
physeal plate that does not contribute to
longitudinal growth (Secondary Centers of
Ossification)
Moore, K. The Developing Human
32. Recap Spinal Cord Development
• Neural tube-- CNS
• Neural Crests-- PNS and ANS
• Neural Canal– Ventricles and central canal
Moore, K. The Developing Human
34. Where Things Go Wrong
• Failure of Canal to Close
Moore, K. The Developing Human
35. Where Things Go Wrong
• Failure of Canal to Close
Moore, K. The Developing Human
36. Where Things Go Wrong
CSF Flow/ Drainage Problems
Chiari malformations- (aka Arnold-Chiari)
definition- downward compression (not
traction) of the lower cerebellar contents into
the cervical region
Typed by amount of displacement-
-correlates with age of onset
-correlates with severity of symptoms
Shrek, H. The Cervical Spine
37. Where Things Go Wrong
CSF Flow/ Drainage Problems
Chiari malformations-
Type I
- mildest
- originally called adult onset
- caudal displacement of cerebellar tonsils
(with dentate ligaments, 4th ventricle, cervical
roots and brain stem in normal position.)
Shrek, H. The Cervical Spine
38. Where Things Go Wrong
CSF Flow/ Drainage Problems
Chiari malformations-
Type II
- more severe
- originally called congenital
- caudal displacement of cerebellar vermis, 4th
ventricle, medulla and lower pons
Shrek, H. The Cervical Spine
39. Where Things Go Wrong
CSF Flow/ Drainage Problems
Chiari malformations-
Type III
- most severe
- caudal displacement of cerebellum and brain
stem into high cervical meningiocele
Shrek, H. The Cervical Spine
40. Chiari Malformations con’t.
• Symptoms- due to neural compression at foramen magnum
– Lower cranial nerve dysfunction
– Long tract signs
• Associated with:
– Scarring
– Compressive atrophy
– Fibrous band
Shrek, H. The Cervical Spine
41. Chiari Malformations con’t.
• Bony deformity = Basilar Impression
– May be secondary to other conditions
– MCC- congenital anomaly in cerv-occ. Area
– Def.- upward movement of base of skull in the foramen magnum area
– Measured by intracranial extension of the tip of odontoid
Shrek, H. The Cervical Spine
42. Basilar Impression- measurement
• Chamberlain’s Line (Red)
– Hard palate to foramen magnum
– Odontoid below line +/- 4 mm.
Shrek, H. The Cervical Spine
43. Basilar Impression- measurement
• McRae’s Line (Green)
– AP of foramen magnum- odontoid below this line
– Symptoms when AP diameter <20 mm.
Shrek, H. The Cervical Spine
44. Basilar Impression- measurement
• Wackenheimer’s Line (Blue)
– Drawn along clivus
– Odontoid is ventral
Shrek, H. The Cervical Spine
45. Fixation +/- Position Changes
• Tethered Cord
– Cause unknown, probably multiple
– Assoc. with cutaneous lesion 54%
– Assoc. with lipoma 15%
– Female 2:1
– Slowly progressive motor dysfunction
– Recovery after surgery- poor- operate early!
Weinstein, S. The Pediatric Spine
46. Fixation +/- Position Changes
• Diastematomyelia
– Cord divided by fibrous, cartilagenous or bony septum
– Cutaneous lesion +/-
– Dural tube- one or two
– Diagnose before spinal instrumentation!
Weinstein, S. The Pediatric Spine