10. Spinal Cord

the Spinal Structures Covering Cord • Vertebrae • Epidural space filled with fat • Dura mater – dense irregular CT tube • Subdural space filled with interstitial fluid • Arachnoid = spider web of collagen fibers • Subarachnoid space = CSF • Pia mater – thin layer covers BV – denticulate ligs hold in place 13-1 An anterior view of the cervical spinal cord showing the meninges, supporting ligaments, and the roots of the spinal nerves Denticulate ligaments Blood vessels within the subarachnoid space Spinal cord nterior median fissure Pia materA Dorsal root Ventral root, formed by several “rootlets” from one cervical segment Arachnoid mater (reflected) Dura mater (reflected) Spinal Cord Protection By the vertebral column, meninges, cerebrospinal fluid, and vertebral ligaments. External Anatomy of Spinal Cord • Flattened cylinder • 16-18 Inches long & 3/4 inch diameter • In adult ends at L2 • In newborn ends at L4 • Growth of cord stops at age • Cervical enlargement – upper limbs • Lumbar enlargement – lower limbs Inferior End of Spinal Cord • Conus medullaris – cone-shaped end of spinal cord • Filum terminale – thread-like extension of pia mater – stabilizes spinal cord in canal • Caudae equinae (horse’s tail) – dorsal & ventral roots of lowest spinal nerves • Spinal segment – area of cord from which each pair of spinal nerves arises 13-5 Spinal Cord & Spinal Nerves • Spinal nerves begin as roots • Dorsal or posterior root is incoming sensory fibers – dorsal root ganglion (swelling) = cell bodies of sensory nerves • Ventral or anterior root is outgoing motor fibers ...................................................CONTINUED............................................