chapter  5
78 Pages

THE EARLY POSTNATAL PERIOD: Infants at 4 days, 4 weeks, and 4 months

Name Myelination

Reactive glia Proliferating glia




dorsal root col. zone --- SparseMyelinated

Myelinated Myelinated

fas. gracilis --- SparseMyelinated fas. cuneatus --- SparseMyelinated

intraspinal tracts --- DenseMany fibers

spinocephalic tracts Very sparse• DenseSome fibers† lat. reticulospinal tract Very sparse SparseSome fibers

spinocerebellar tracts --- SparseMyelinated

med. long. fasiculus --- SparseSome fibers vestibulospinal tract --- SparseSome fibers

dorsal root bif. zone Many fibers* Sparse






ven. commissure Myelinated Dense---

Lissauer's tract Sparse--- None

lat. cortricospinal tract Sparse--- Very sparse ven. cortricospinal tract Sparse--- Very sparse

** dense band in a sparse field (part of the boundary cap?) * intermingled in a bed of nonreactive glia † few fibers at the cervical level • peripheral fibers at the cervical level

Plates 84A, 84B Lower Thoracic Total Area: 7.7961 mm2

Plates 85A, 85B Lower Thoracic

Total Area: 8.2168 mm2

Plates 82A, 82B Upper Thoracic Total Area: 10.177 mm2

Plates 83A, 83B Upper Thoracic

Total Area: 10.514 mm2

Plates 86A, 86B Upper Lumbar Total Area: 11.735 mm2

Plates 87A, 87B Upper Lumbar

Total Area: 12.730 mm2

Plates 88A, 88B Lumbar Enlargement Total Area: 12.152 mm2

Plates 90A, 90B Sacral/Coccygeal Total Area: 5.6792 mm2

Plates 89A, 89B Lumbar

Enlargement Total Area:

12.162 mm2

Plates 80A, 80B Cervical Enlargement Total Area: 20.063 mm2

Plates 81A, 81B Cervical

Enlargement Total Area:

21.370 mm2

Plates 91A, 91B Sacral/Coccygeal

Total Area: 5.9052 mm2

Central canal .0029 Ependyma .0119 Gray matter 6.9875 White matter 13.0610

c e p h

a l i c

c t s

Tectospinal tract? Medial longitudinal fasciculus?