chapter  4
52 Pages

THE THIRD TRIMESTER

Name Myelination

Reactive glia Proliferating glia

DORSAL FUNICULUS:

LATERAL and VENTRAL FUNICULI:

dorsal root col. zone --- Very denseMany fibers deep fas. gracilis --- Very denseMany fibers superficial fas. gracilis Dense DenseSome fibers

lat. reticulospinal tract Dense SparseSome fibers intraspinal tracts Dense SparseSome fibers spinocephalic tracts

rubrospinal tract

Dense SparseSome fibers

spinocerebellar tracts Dense DenseSome fibers Dense SparseSome fibers

vestibulospinal tract Dense SparseSome fibers

dorsal root bif. zone Many fibers* Sparse---

ven. commissure Many fibers Sparse---

Lissauer's tract Very sparse--- None

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

* intermingled in a bed of nonreactive glia (associated with Lissauer's tract fibers?)

Plates 54A, 54B Lower Thoracic Total area: 5.1272 mm2

Plates 55A, 55B Lower Thoracic

Total area: 5.2380 mm2

Plates 56A, 56B Upper Lumbar Total area: 6.9121 mm2

Plates 57A, 57B Upper Lumbar

Total area: 7.1380 mm2

Plates 58A, 58B Lumbar Enlargement Total area: 9.7553 mm2

Plates 60A, 60B Sacral/Coccygeal Total area: 3.5153 mm2

Plates 59A, 59B Lumbar Enlargement

Total area: 10.918 mm2

Plates 61A, 61B Sacral/Coccygeal

Total area: 3.5751 mm2

Central canal .0012 Ependyma .0057 Gray matter 1.4171 White matter 3.7032

Ventral white commissure Ventral gray commissure

Ventral corticospinal tract?